DOKK / manpages / debian 12 / ovn-common / ovn-sb.5.en
ovn-sb(5) Open vSwitch Manual ovn-sb(5)

ovn-sb - OVN_Southbound database schema

This database holds logical and physical configuration and state for the Open Virtual Network (OVN) system to support virtual network abstraction. For an introduction to OVN, please see ovn-architecture(7).

The OVN Southbound database sits at the center of the OVN architecture. It is the one component that speaks both southbound directly to all the hypervisors and gateways, via ovn-controller/ovn-controller-vtep, and northbound to the Cloud Management System, via ovn-northd:

The OVN Southbound database contains classes of data with different properties, as described in the sections below.

Physical network

Physical network tables contain information about the chassis nodes in the system. This contains all the information necessary to wire the overlay, such as IP addresses, supported tunnel types, and security keys.

The amount of physical network data is small (O(n) in the number of chassis) and it changes infrequently, so it can be replicated to every chassis.

The Chassis and Encap tables are the physical network tables.

Logical Network

Logical network tables contain the topology of logical switches and routers, ACLs, firewall rules, and everything needed to describe how packets traverse a logical network, represented as logical datapath flows (see Logical Datapath Flows, below).

Logical network data may be large (O(n) in the number of logical ports, ACL rules, etc.). Thus, to improve scaling, each chassis should receive only data related to logical networks in which that chassis participates.

The logical network data is ultimately controlled by the cloud management system (CMS) running northbound of OVN. That CMS determines the entire OVN logical configuration and therefore the logical network data at any given time is a deterministic function of the CMS’s configuration, although that happens indirectly via the OVN_Northbound database and ovn-northd.

Logical network data is likely to change more quickly than physical network data. This is especially true in a container environment where containers are created and destroyed (and therefore added to and deleted from logical switches) quickly.

The Logical_Flow, Multicast_Group, Address_Group, DHCP_Options, DHCPv6_Options, and DNS tables contain logical network data.

Logical-physical bindings

These tables link logical and physical components. They show the current placement of logical components (such as VMs and VIFs) onto chassis, and map logical entities to the values that represent them in tunnel encapsulations.

These tables change frequently, at least every time a VM powers up or down or migrates, and especially quickly in a container environment. The amount of data per VM (or VIF) is small.

Each chassis is authoritative about the VMs and VIFs that it hosts at any given time and can efficiently flood that state to a central location, so the consistency needs are minimal.

The Port_Binding and Datapath_Binding tables contain binding data.

MAC bindings

The MAC_Binding table tracks the bindings from IP addresses to Ethernet addresses that are dynamically discovered using ARP (for IPv4) and neighbor discovery (for IPv6). Usually, IP-to-MAC bindings for virtual machines are statically populated into the Port_Binding table, so MAC_Binding is primarily used to discover bindings on physical networks.

Some tables contain a special column named external_ids. This column has the same form and purpose each place that it appears, so we describe it here to save space later.

Key-value pairs for use by the software that manages the OVN Southbound database rather than by ovn-controller/ovn-controller-vtep. In particular, ovn-northd can use key-value pairs in this column to relate entities in the southbound database to higher-level entities (such as entities in the OVN Northbound database). Individual key-value pairs in this column may be documented in some cases to aid in understanding and troubleshooting, but the reader should not mistake such documentation as comprehensive.

The following list summarizes the purpose of each of the tables in the OVN_Southbound database. Each table is described in more detail on a later page.

Purpose
Southbound configuration
Physical Network Hypervisor and Gateway Information
Chassis Private
Encapsulation Types
Address Sets
Port Groups
Logical Network Flows
Logical Datapath Groups
Logical Port Multicast Groups
Mirror Entry
Meter entry
Band for meter entries
Physical-Logical Datapath Bindings
Physical-Logical Port Bindings
IP to MAC bindings
DHCP Options supported by native OVN DHCP
DHCPv6 Options supported by native OVN DHCPv6
OVSDB client connections.
SSL configuration.
Native DNS resolution
RBAC_Role configuration.
RBAC_Permission configuration.
Gateway_Chassis configuration.
HA_Chassis configuration.
HA_Chassis_Group configuration.
Controller Event table
IP_Multicast configuration.
IGMP_Group configuration.
Service_Monitor configuration.
Load_Balancer configuration.
BFD configuration.
Port to MAC bindings
IP to MAC bindings
Chassis_Template_Var configuration.

Southbound configuration for an OVN system. This table must have exactly one row.


integer


map of string-string pairs
map of string-string pairs


map of string-string pairs

optional string
optional string
optional string
optional string
optional string
optional string


optional string


set of Connections
optional SSL


boolean

Status:

This column allow a client to track the overall configuration state of the system.

Sequence number for the configuration. When a CMS or ovn-nbctl updates the northbound database, it increments the nb_cfg column in the NB_Global table in the northbound database. In turn, when ovn-northd updates the southbound database to bring it up to date with these changes, it updates this column to the same value.

Common Columns:
See External IDs at the beginning of this document.

Common options:
This column provides general key/value settings. The supported options are described individually below.

Options for configuring BFD:

These options apply when ovn-controller configures BFD on tunnels interfaces.

BFD option min-rx value to use when configuring BFD on tunnel interfaces.
BFD option decay-min-rx value to use when configuring BFD on tunnel interfaces.
BFD option min-tx value to use when configuring BFD on tunnel interfaces.
BFD option mult value to use when configuring BFD on tunnel interfaces.
If set to a 8-bit number and if debug_drop_collector_set is also configured, ovn-controller will add a sample action to every flow that does not come from a logical flow that contains a ’drop’ action. The 8 most significant bits of the observation_domain_id field will be those specified in the debug_drop_domain_id. The 24 least significant bits of the observation_domain_id field will be zero.
The observation_point_id will be set to the OpenFlow table number.
If set to a 32-bit number ovn-controller will add a sample action to every flow that does not come from a logical flow that contains a ’drop’ action. The sample action will have the specified collector_set_id. The value must match that of the local OVS configuration as described in ovs-actions(7).

Options for configuring Load Balancers:

These options apply when ovn-controller configures load balancer related flows.

By default this option is turned on (even if not present in the database) unless its value is explicitly set to false. This value is automatically set to false by ovn-northd when action ct_lb_mark cannot be used for new load balancer sessions and action ct_lb will be used instead. ovn-controller then knows that it should check ct_label.natted to detect load balanced traffic.

Connection Options:
Database clients to which the Open vSwitch database server should connect or on which it should listen, along with options for how these connections should be configured. See the Connection table for more information.
Global SSL configuration.

Security Configurations:
Tunnel encryption configuration. If this column is set to be true, all OVN tunnels will be encrypted with IPsec.

Each row in this table represents a hypervisor or gateway (a chassis) in the physical network. Each chassis, via ovn-controller/ovn-controller-vtep, adds and updates its own row, and keeps a copy of the remaining rows to determine how to reach other hypervisors.

When a chassis shuts down gracefully, it should remove its own row. (This is not critical because resources hosted on the chassis are equally unreachable regardless of whether the row is present.) If a chassis shuts down permanently without removing its row, some kind of manual or automatic cleanup is eventually needed; we can devise a process for that as necessary.

string (must be unique within table)
string
integer
optional string
optional string
optional string
optional string
optional string
optional string
set of strings
optional string
optional string

map of string-string pairs


set of 1 or more Encaps


set of strings

OVN does not prescribe a particular format for chassis names. ovn-controller populates this column using external_ids:system-id in the Open_vSwitch database’s Open_vSwitch table. ovn-controller-vtep populates this column with name in the hardware_vtep database’s Physical_Switch table.
The hostname of the chassis, if applicable. ovn-controller will populate this column with the hostname of the host it is running on. ovn-controller-vtep will leave this column empty.
Deprecated. This column is replaced by the nb_cfg column of the Chassis_Private table.
ovn-controller populates this key with the set of bridge mappings it has been configured to use. Other applications should treat this key as read-only. See ovn-controller(8) for more information.
ovn-controller populates this key with the datapath type configured in the datapath_type column of the Open_vSwitch database’s Bridge table. Other applications should treat this key as read-only. See ovn-controller(8) for more information.
ovn-controller populates this key with the interface types configured in the iface_types column of the Open_vSwitch database’s Open_vSwitch table. Other applications should treat this key as read-only. See ovn-controller(8) for more information.
ovn-controller populates this key with the set of options configured in the external_ids:ovn-cms-options column of the Open_vSwitch database’s Open_vSwitch table. See ovn-controller(8) for more information.
ovn-controller populates this key with the setting configured in the external_ids:ovn-is-interconn column of the Open_vSwitch database’s Open_vSwitch table. If set to true, the chassis is used as an interconnection gateway. See ovn-controller(8) for more information.
ovn-ic set this key to true for remote interconnection gateway chassises learned from the interconnection southbound database. See ovn-ic(8) for more information.
ovn-controller populates this key with the transport zones configured in the external_ids:ovn-transport-zones column of the Open_vSwitch database’s Open_vSwitch table. See ovn-controller(8) for more information.
ovn-controller populates this key with the set of options configured in the external_ids:ovn-chassis-mac-mappings column of the Open_vSwitch database’s Open_vSwitch table. See ovn-controller(8) for more information.
ovn-controller populates this key with true when it supports Port_Binding.up.

Common Columns:

The overall purpose of these columns is described under Common Columns at the beginning of this document.

Encapsulation Configuration:

OVN uses encapsulation to transmit logical dataplane packets between chassis.

Points to supported encapsulation configurations to transmit logical dataplane packets to this chassis. Each entry is a Encap record that describes the configuration.

Gateway Configuration:

A gateway is a chassis that forwards traffic between the OVN-managed part of a logical network and a physical VLAN, extending a tunnel-based logical network into a physical network. Gateways are typically dedicated nodes that do not host VMs and will be controlled by ovn-controller-vtep.

Stores all VTEP logical switch names connected by this gateway chassis. The Port_Binding table entry with options:vtep-physical-switch equal Chassis name, and options:vtep-logical-switch value in Chassis vtep_logical_switches, will be associated with this Chassis.

Each row in this table maintains per chassis private data that are accessed only by the owning chassis (write only) and ovn-northd, not by any other chassis. These data are stored in this separate table instead of the Chassis table for performance considerations: the rows in this table can be conditionally monitored by chassises so that each chassis only get update notifications for its own row, to avoid unnecessary chassis private data update flooding in a large scale deployment.

string (must be unique within table)
optional weak reference to Chassis
integer
integer

map of string-string pairs

The name of the chassis that owns these chassis-private data.
The reference to Chassis table for the chassis that owns these chassis-private data.
Sequence number for the configuration. When ovn-controller updates the configuration of a chassis from the contents of the southbound database, it copies nb_cfg from the SB_Global table into this column.
The timestamp when ovn-controller finishes processing the change corresponding to nb_cfg.

Common Columns:

The overall purpose of these columns is described under Common Columns at the beginning of this document.

The encaps column in the Chassis table refers to rows in this table to identify how OVN may transmit logical dataplane packets to this chassis. Each chassis, via ovn-controller(8) or ovn-controller-vtep(8), adds and updates its own rows and keeps a copy of the remaining rows to determine how to reach other chassis.

string, one of geneve, stt, or vxlan
map of string-string pairs
optional string, either true or false
optional string, containing an integer
string
string

The encapsulation to use to transmit packets to this chassis. Hypervisors must use either geneve or stt. Gateways may use vxlan, geneve, or stt.
Options for configuring the encapsulation, which may be type specific.
csum indicates whether this chassis can transmit and receive packets that include checksums with reasonable performance. It hints to senders transmitting data to this chassis that they should use checksums to protect OVN metadata. ovn-controller populates this key with the value defined in external_ids:ovn-encap-csum column of the Open_vSwitch database’s Open_vSwitch table. Other applications should treat this key as read-only. See ovn-controller(8) for more information.
In terms of performance, checksumming actually significantly increases throughput in most common cases when running on Linux based hosts without NICs supporting encapsulation hardware offload (around 60% for bulk traffic). The reason is that generally all NICs are capable of offloading transmitted and received TCP/UDP checksums (viewed as ordinary data packets and not as tunnels). The benefit comes on the receive side where the validated outer checksum can be used to additionally validate an inner checksum (such as TCP), which in turn allows aggregation of packets to be more efficiently handled by the rest of the stack.
Not all devices see such a benefit. The most notable exception is hardware VTEPs. These devices are designed to not buffer entire packets in their switching engines and are therefore unable to efficiently compute or validate full packet checksums. In addition certain versions of the Linux kernel are not able to fully take advantage of encapsulation NIC offloads in the presence of checksums. (This is actually a pretty narrow corner case though: earlier versions of Linux don’t support encapsulation offloads at all and later versions support both offloads and checksums well.)
csum defaults to false for hardware VTEPs and true for all other cases.
This option applies to geneve and vxlan encapsulations.
If set, overrides the UDP (for geneve and vxlan) or TCP (for stt) destination port.
The IPv4 address of the encapsulation tunnel endpoint.
The name of the chassis that created this encap.

This table contains address sets synced from the Address_Set table in the OVN_Northbound database and address sets generated from the Port_Group table in the OVN_Northbound database.

See the documentation for the Address_Set table and Port_Group table in the OVN_Northbound database for details.

string (must be unique within table)
set of strings

This table contains names for the logical switch ports in the OVN_Northbound database that belongs to the same group that is defined in Port_Group in the OVN_Northbound database.

string (must be unique within table)
set of strings

Each row in this table represents one logical flow. ovn-northd populates this table with logical flows that implement the L2 and L3 topologies specified in the OVN_Northbound database. Each hypervisor, via ovn-controller, translates the logical flows into OpenFlow flows specific to its hypervisor and installs them into Open vSwitch.

Logical flows are expressed in an OVN-specific format, described here. A logical datapath flow is much like an OpenFlow flow, except that the flows are written in terms of logical ports and logical datapaths instead of physical ports and physical datapaths. Translation between logical and physical flows helps to ensure isolation between logical datapaths. (The logical flow abstraction also allows the OVN centralized components to do less work, since they do not have to separately compute and push out physical flows to each chassis.)

The default action when no flow matches is to drop packets.

Architectural Logical Life Cycle of a Packet

This following description focuses on the life cycle of a packet through a logical datapath, ignoring physical details of the implementation. Please refer to Architectural Physical Life Cycle of a Packet in ovn-architecture(7) for the physical information.

The description here is written as if OVN itself executes these steps, but in fact OVN (that is, ovn-controller) programs Open vSwitch, via OpenFlow and OVSDB, to execute them on its behalf.

At a high level, OVN passes each packet through the logical datapath’s logical ingress pipeline, which may output the packet to one or more logical port or logical multicast groups. For each such logical output port, OVN passes the packet through the datapath’s logical egress pipeline, which may either drop the packet or deliver it to the destination. Between the two pipelines, outputs to logical multicast groups are expanded into logical ports, so that the egress pipeline only processes a single logical output port at a time. Between the two pipelines is also where, when necessary, OVN encapsulates a packet in a tunnel (or tunnels) to transmit to remote hypervisors.

In more detail, to start, OVN searches the Logical_Flow table for a row with correct logical_datapath or a logical_dp_group, a pipeline of ingress, a table_id of 0, and a match that is true for the packet. If none is found, OVN drops the packet. If OVN finds more than one, it chooses the match with the highest priority. Then OVN executes each of the actions specified in the row’s actions column, in the order specified. Some actions, such as those to modify packet headers, require no further details. The next and output actions are special.

The next action causes the above process to be repeated recursively, except that OVN searches for table_id of 1 instead of 0. Similarly, any next action in a row found in that table would cause a further search for a table_id of 2, and so on. When recursive processing completes, flow control returns to the action following next.

The output action also introduces recursion. Its effect depends on the current value of the outport field. Suppose outport designates a logical port. First, OVN compares inport to outport; if they are equal, it treats the output as a no-op by default. In the common case, where they are different, the packet enters the egress pipeline. This transition to the egress pipeline discards register data, e.g. reg0 ... reg9 and connection tracking state, to achieve uniform behavior regardless of whether the egress pipeline is on a different hypervisor (because registers aren’t preserve across tunnel encapsulation).

To execute the egress pipeline, OVN again searches the Logical_Flow table for a row with correct logical_datapath or a logical_dp_group, a table_id of 0, a match that is true for the packet, but now looking for a pipeline of egress. If no matching row is found, the output becomes a no-op. Otherwise, OVN executes the actions for the matching flow (which is chosen from multiple, if necessary, as already described).

In the egress pipeline, the next action acts as already described, except that it, of course, searches for egress flows. The output action, however, now directly outputs the packet to the output port (which is now fixed, because outport is read-only within the egress pipeline).

The description earlier assumed that outport referred to a logical port. If it instead designates a logical multicast group, then the description above still applies, with the addition of fan-out from the logical multicast group to each logical port in the group. For each member of the group, OVN executes the logical pipeline as described, with the logical output port replaced by the group member.

Pipeline Stages

ovn-northd populates the Logical_Flow table with the logical flows described in detail in ovn-northd(8).

optional Datapath_Binding
optional Logical_DP_Group
string, either egress or ingress
integer, in range 0 to 32
integer, in range 0 to 65,535
string
string
map of string-string pairs
optional string
optional string
optional string, containing an uuid
optional string

map of string-string pairs

The logical datapath to which the logical flow belongs.
The group of logical datapaths to which the logical flow belongs. This means that the same logical flow belongs to all datapaths in a group.
The primary flows used for deciding on a packet’s destination are the ingress flows. The egress flows implement ACLs. See Logical Life Cycle of a Packet, above, for details.
The stage in the logical pipeline, analogous to an OpenFlow table number.
The flow’s priority. Flows with numerically higher priority take precedence over those with lower. If two logical datapath flows with the same priority both match, then the one actually applied to the packet is undefined.
A matching expression. OVN provides a superset of OpenFlow matching capabilities, using a syntax similar to Boolean expressions in a programming language.
The most important components of match expression are comparisons between symbols and constants, e.g. ip4.dst == 192.168.0.1, ip.proto == 6, arp.op == 1, eth.type == 0x800. The logical AND operator && and logical OR operator || can combine comparisons into a larger expression.
Matching expressions also support parentheses for grouping, the logical NOT prefix operator !, and literals 0 and 1 to express ``false’’ or ``true,’’ respectively. The latter is useful by itself as a catch-all expression that matches every packet.
Match expressions also support a kind of function syntax. The following functions are supported:
Evaluates to true on a chassis on which logical port lport (a quoted string) resides, and to false elsewhere. This function was introduced in OVN 2.7.
Symbols
Type. Symbols have integer or string type. Integer symbols have a width in bits.
Kinds. There are three kinds of symbols:
•
Fields. A field symbol represents a packet header or metadata field. For example, a field named vlan.tci might represent the VLAN TCI field in a packet.
A field symbol can have integer or string type. Integer fields can be nominal or ordinal (see Level of Measurement, below).
•
Subfields. A subfield represents a subset of bits from a larger field. For example, a field vlan.vid might be defined as an alias for vlan.tci[0..11]. Subfields are provided for syntactic convenience, because it is always possible to instead refer to a subset of bits from a field directly.
Only ordinal fields (see Level of Measurement, below) may have subfields. Subfields are always ordinal.
•
Predicates. A predicate is shorthand for a Boolean expression. Predicates may be used much like 1-bit fields. For example, ip4 might expand to eth.type == 0x800. Predicates are provided for syntactic convenience, because it is always possible to instead specify the underlying expression directly.
A predicate whose expansion refers to any nominal field or predicate (see Level of Measurement, below) is nominal; other predicates have Boolean level of measurement.
Level of Measurement. See http://en.wikipedia.org/wiki/Level_of_measurement for the statistical concept on which this classification is based. There are three levels:
•
Ordinal. In statistics, ordinal values can be ordered on a scale. OVN considers a field (or subfield) to be ordinal if its bits can be examined individually. This is true for the OpenFlow fields that OpenFlow or Open vSwitch makes ``maskable.’’
Any use of a ordinal field may specify a single bit or a range of bits, e.g. vlan.tci[13..15] refers to the PCP field within the VLAN TCI, and eth.dst[40] refers to the multicast bit in the Ethernet destination address.
OVN supports all the usual arithmetic relations (==, !=, <, <=, >, and >=) on ordinal fields and their subfields, because OVN can implement these in OpenFlow and Open vSwitch as collections of bitwise tests.
•
Nominal. In statistics, nominal values cannot be usefully compared except for equality. This is true of OpenFlow port numbers, Ethernet types, and IP protocols are examples: all of these are just identifiers assigned arbitrarily with no deeper meaning. In OpenFlow and Open vSwitch, bits in these fields generally aren’t individually addressable.
OVN only supports arithmetic tests for equality on nominal fields, because OpenFlow and Open vSwitch provide no way for a flow to efficiently implement other comparisons on them. (A test for inequality can be sort of built out of two flows with different priorities, but OVN matching expressions always generate flows with a single priority.)
String fields are always nominal.
•
Boolean. A nominal field that has only two values, 0 and 1, is somewhat exceptional, since it is easy to support both equality and inequality tests on such a field: either one can be implemented as a test for 0 or 1.
Only predicates (see above) have a Boolean level of measurement.
This isn’t a standard level of measurement.
Prerequisites. Any symbol can have prerequisites, which are additional condition implied by the use of the symbol. For example, For example, icmp4.type symbol might have prerequisite icmp4, which would cause an expression icmp4.type == 0 to be interpreted as icmp4.type == 0 && icmp4, which would in turn expand to icmp4.type == 0 && eth.type == 0x800 && ip4.proto == 1 (assuming icmp4 is a predicate defined as suggested under Types above).
Relational operators
All of the standard relational operators ==, !=, <, <=, >, and >= are supported. Nominal fields support only == and !=, and only in a positive sense when outer ! are taken into account, e.g. given string field inport, inport == "eth0" and !(inport != "eth0") are acceptable, but not inport != "eth0".
The implementation of == (or != when it is negated), is more efficient than that of the other relational operators.
Constants
Integer constants may be expressed in decimal, hexadecimal prefixed by 0x, or as dotted-quad IPv4 addresses, IPv6 addresses in their standard forms, or Ethernet addresses as colon-separated hex digits. A constant in any of these forms may be followed by a slash and a second constant (the mask) in the same form, to form a masked constant. IPv4 and IPv6 masks may be given as integers, to express CIDR prefixes.
String constants have the same syntax as quoted strings in JSON (thus, they are Unicode strings).
Some operators support sets of constants written inside curly braces { ... }. Commas between elements of a set, and after the last elements, are optional. With ==, ``field == { constant1, constant2, ... }’’ is syntactic sugar for ``field == constant1 || field == constant2 || .... Similarly, ``field != { constant1, constant2, ... }’’ is equivalent to ``field != constant1 && field != constant2 && ...’’.
You may refer to a set of IPv4, IPv6, or MAC addresses stored in the Address_Set table by its name. An Address_Set with a name of set1 can be referred to as $set1.
You may refer to a group of logical switch ports stored in the Port_Group table by its name. An Port_Group with a name of port_group1 can be referred to as @port_group1.
Additionally, you may refer to the set of addresses belonging to a group of logical switch ports stored in the Port_Group table by its name followed by a suffix ’_ip4’/’_ip6’. The IPv4 address set of a Port_Group with a name of port_group1 can be referred to as $port_group1_ip4, and the IPv6 address set of the same Port_Group can be referred to as $port_group1_ip6
Miscellaneous
Comparisons may name the symbol or the constant first, e.g. tcp.src == 80 and 80 == tcp.src are both acceptable.
Tests for a range may be expressed using a syntax like 1024 <= tcp.src <= 49151, which is equivalent to 1024 <= tcp.src && tcp.src <= 49151.
For a one-bit field or predicate, a mention of its name is equivalent to symobl == 1, e.g. vlan.present is equivalent to vlan.present == 1. The same is true for one-bit subfields, e.g. vlan.tci[12]. There is no technical limitation to implementing the same for ordinal fields of all widths, but the implementation is expensive enough that the syntax parser requires writing an explicit comparison against zero to make mistakes less likely, e.g. in tcp.src != 0 the comparison against 0 is required.
Operator precedence is as shown below, from highest to lowest. There are two exceptions where parentheses are required even though the table would suggest that they are not: && and || require parentheses when used together, and ! requires parentheses when applied to a relational expression. Thus, in (eth.type == 0x800 || eth.type == 0x86dd) && ip.proto == 6 or !(arp.op == 1), the parentheses are mandatory.
  • ()
  • == != < <= > >=
  • !
  • && ||
Comments may be introduced by //, which extends to the next new-line. Comments within a line may be bracketed by /* and */. Multiline comments are not supported.
Symbols
Most of the symbols below have integer type. Only inport and outport have string type. inport names a logical port. Thus, its value is a logical_port name from the Port_Binding table. outport may name a logical port, as inport, or a logical multicast group defined in the Multicast_Group table. For both symbols, only names within the flow’s logical datapath may be used.
The regX symbols are 32-bit integers. The xxregX symbols are 128-bit integers, which overlay four of the 32-bit registers: xxreg0 overlays reg0 through reg3, with reg0 supplying the most-significant bits of xxreg0 and reg3 the least-significant. xxreg1 similarly overlays reg4 through reg7.
  • reg0...reg9
  • xxreg0 xxreg1
  • inport outport
  • flags.loopback
  • pkt.mark
  • eth.src eth.dst eth.type
  • vlan.tci vlan.vid vlan.pcp vlan.present
  • ip.proto ip.dscp ip.ecn ip.ttl ip.frag
  • ip4.src ip4.dst
  • ip6.src ip6.dst ip6.label
  • arp.op arp.spa arp.tpa arp.sha arp.tha
  • rarp.op rarp.spa rarp.tpa rarp.sha rarp.tha
  • tcp.src tcp.dst tcp.flags
  • udp.src udp.dst
  • sctp.src sctp.dst
  • icmp4.type icmp4.code
  • icmp6.type icmp6.code
  • nd.target nd.sll nd.tll
  • ct_mark ct_label
  • ct_state, which has several Boolean subfields. The ct_next action initializes the following subfields:
  • ct.trk: Always set to true by ct_next to indicate that connection tracking has taken place. All other ct subfields have ct.trk as a prerequisite.
  • ct.new: True for a new flow
  • ct.est: True for an established flow
  • ct.rel: True for a related flow
  • ct.rpl: True for a reply flow
  • ct.inv: True for a connection entry in a bad state
The ct_dnat, ct_snat, and ct_lb actions initialize the following subfields:
  • ct.dnat: True for a packet whose destination IP address has been changed.
  • ct.snat: True for a packet whose source IP address has been changed.
The following predicates are supported:
  • eth.bcast expands to eth.dst == ff:ff:ff:ff:ff:ff
  • eth.mcast expands to eth.dst[40]
  • vlan.present expands to vlan.tci[12]
  • ip4 expands to eth.type == 0x800
  • ip4.src_mcast expands to ip4.src[28..31] == 0xe
  • ip4.mcast expands to ip4.dst[28..31] == 0xe
  • ip6 expands to eth.type == 0x86dd
  • ip expands to ip4 || ip6
  • icmp4 expands to ip4 && ip.proto == 1
  • icmp6 expands to ip6 && ip.proto == 58
  • icmp expands to icmp4 || icmp6
  • ip.is_frag expands to ip.frag[0]
  • ip.later_frag expands to ip.frag[1]
  • ip.first_frag expands to ip.is_frag && !ip.later_frag
  • arp expands to eth.type == 0x806
  • rarp expands to eth.type == 0x8035
  • nd expands to icmp6.type == {135, 136} && icmp6.code == 0 && ip.ttl == 255
  • nd_ns expands to icmp6.type == 135 && icmp6.code == 0 && ip.ttl == 255
  • nd_na expands to icmp6.type == 136 && icmp6.code == 0 && ip.ttl == 255
  • nd_rs expands to icmp6.type == 133 && icmp6.code == 0 && ip.ttl == 255
  • nd_ra expands to icmp6.type == 134 && icmp6.code == 0 && ip.ttl == 255
  • tcp expands to ip.proto == 6
  • udp expands to ip.proto == 17
  • sctp expands to ip.proto == 132
Logical datapath actions, to be executed when the logical flow represented by this row is the highest-priority match.
Actions share lexical syntax with the match column. An empty set of actions (or one that contains just white space or comments), or a set of actions that consists of just drop;, causes the matched packets to be dropped. Otherwise, the column should contain a sequence of actions, each terminated by a semicolon.
The following actions are defined:
In the ingress pipeline, this action executes the egress pipeline as a subroutine. If outport names a logical port, the egress pipeline executes once; if it is a multicast group, the egress pipeline runs once for each logical port in the group.
In the egress pipeline, this action performs the actual output to the outport logical port. (In the egress pipeline, outport never names a multicast group.)
By default, output to the input port is implicitly dropped, that is, output becomes a no-op if outport == inport. Occasionally it may be useful to override this behavior, e.g. to send an ARP reply to an ARP request; to do so, use flags.loopback = 1 to allow the packet to "hair-pin" back to the input port.


Executes the given logical datapath table in pipeline as a subroutine. The default table is just after the current one. If pipeline is specified, it may be ingress or egress; the default pipeline is the one currently executing. Actions in the both ingress and egress pipeline can use next to jump across the other pipeline. Actions in the ingress pipeline should use next to jump into the specific table of egress pipeline only if it is certain that the packets are local and not tunnelled and wants to skip certain stages in the packet processing.
Sets data or metadata field field to constant value constant, e.g. outport = "vif0"; to set the logical output port. To set only a subset of bits in a field, specify a subfield for field or a masked constant, e.g. one may use vlan.pcp[2] = 1; or vlan.pcp = 4/4; to set the most significant bit of the VLAN PCP.
Assigning to a field with prerequisites implicitly adds those prerequisites to match; thus, for example, a flow that sets tcp.dst applies only to TCP flows, regardless of whether its match mentions any TCP field.
Not all fields are modifiable (e.g. eth.type and ip.proto are read-only), and not all modifiable fields may be partially modified (e.g. ip.ttl must assigned as a whole). The outport field is modifiable in the ingress pipeline but not in the egress pipeline.
Sets OVN field ovn_field to constant value constant.
OVN supports setting the values of certain fields which are not yet supported in OpenFlow to set or modify them.
Below are the supported OVN fields:
•
icmp4.frag_mtu icmp6.frag_mtu
This field sets the low-order 16 bits of the ICMP{4,6} header field that is labelled "unused" in the ICMP specification as defined in the RFC 1191 with the value specified in constant.
Eg. icmp4.frag_mtu = 1500;
Sets data or metadata field field1 to the value of data or metadata field field2, e.g. reg0 = ip4.src; copies ip4.src into reg0. To modify only a subset of a field’s bits, specify a subfield for field1 or field2 or both, e.g. vlan.pcp = reg0[0..2]; copies the least-significant bits of reg0 into the VLAN PCP.
field1 and field2 must be the same type, either both string or both integer fields. If they are both integer fields, they must have the same width.
If field1 or field2 has prerequisites, they are added implicitly to match. It is possible to write an assignment with contradictory prerequisites, such as ip4.src = ip6.src[0..31];, but the contradiction means that a logical flow with such an assignment will never be matched.
Similar to field1 = field2; except that the two values are exchanged instead of copied. Both field1 and field2 must modifiable.
Push the value of field to the stack top.
Pop the stack top and store the value to field, which must be modifiable.
Decrements the IPv4 or IPv6 TTL. If this would make the TTL zero or negative, then processing of the packet halts; no further actions are processed. (To properly handle such cases, a higher-priority flow should match on ip.ttl == {0, 1};.)
Prerequisite: ip
Apply connection tracking to the flow, initializing ct_state for matching in later tables. Automatically moves on to the next table, as if followed by next.
As a side effect, IP fragments will be reassembled for matching. If a fragmented packet is output, then it will be sent with any overlapping fragments squashed. The connection tracking state is scoped by the logical port when the action is used in a flow for a logical switch, so overlapping addresses may be used. To allow traffic related to the matched flow, execute ct_commit . Connection tracking state is scoped by the logical topology when the action is used in a flow for a router.
It is possible to have actions follow ct_next, but they will not have access to any of its side-effects and is not generally useful.



Commit the flow to the connection tracking entry associated with it by a previous call to ct_next. When ct_mark=value[/mask] and/or ct_label=value[/mask] are supplied, ct_mark and/or ct_label will be set to the values indicated by value[/mask] on the connection tracking entry. ct_mark is a 32-bit field. ct_label is a 128-bit field. The value[/mask] should be specified in hex string if more than 64bits are to be used. Registers and other named fields can be used for value. ct_mark and ct_label may be sub-addressed in order to have specific bits set.
Note that if you want processing to continue in the next table, you must execute the next action after ct_commit. You may also leave out next which will commit connection tracking state, and then drop the packet. This could be useful for setting ct_mark on a connection tracking entry before dropping a packet, for example.

ct_dnat sends the packet through the DNAT zone in connection tracking table to unDNAT any packet that was DNATed in the opposite direction. The packet is then automatically sent to to the next tables as if followed by next; action. The next tables will see the changes in the packet caused by the connection tracker.
ct_dnat(IP) sends the packet through the DNAT zone to change the destination IP address of the packet to the one provided inside the parentheses and commits the connection. The packet is then automatically sent to the next tables as if followed by next; action. The next tables will see the changes in the packet caused by the connection tracker.

ct_snat sends the packet through the SNAT zone to unSNAT any packet that was SNATed in the opposite direction. The packet is automatically sent to the next tables as if followed by the next; action. The next tables will see the changes in the packet caused by the connection tracker.
ct_snat(IP) sends the packet through the SNAT zone to change the source IP address of the packet to the one provided inside the parenthesis and commits the connection. The packet is then automatically sent to the next tables as if followed by next; action. The next tables will see the changes in the packet caused by the connection tracker.

ct_dnat_in_czone sends the packet through the common NAT zone (used for both DNAT and SNAT) in connection tracking table to unDNAT any packet that was DNATed in the opposite direction. The packet is then automatically sent to to the next tables as if followed by next; action. The next tables will see the changes in the packet caused by the connection tracker.
ct_dnat_in_czone(IP) sends the packet through the common NAT zone to change the destination IP address of the packet to the one provided inside the parentheses and commits the connection. The packet is then automatically sent to the next tables as if followed by next; action. The next tables will see the changes in the packet caused by the connection tracker.

ct_snat_in_czone sends the packet through the common NAT zone to unSNAT any packet that was SNATed in the opposite direction. The packet is automatically sent to the next tables as if followed by the next; action. The next tables will see the changes in the packet caused by the connection tracker.
ct_snat_in_czone(IP) sends the packet\ through the common NAT zone to change the source IP address of the packet to the one provided inside the parenthesis and commits the connection. The packet is then automatically sent to the next tables as if followed by next; action. The next tables will see the changes in the packet caused by the connection tracker.
Clears connection tracking state.
Applies NAT and commits the connection to the CT. Automatically moves on to the next table, as if followed by next. This is very useful for connections that are in related state for already existing connections and allows the NAT to be applied to them as well.
Makes a copy of the packet being processed and executes each action on the copy. Actions following the clone action, if any, apply to the original, unmodified packet. This can be used as a way to ``save and restore’’ the packet around a set of actions that may modify it and should not persist.
Temporarily replaces the IPv4 packet being processed by an ARP packet and executes each nested action on the ARP packet. Actions following the arp action, if any, apply to the original, unmodified packet.
The ARP packet that this action operates on is initialized based on the IPv4 packet being processed, as follows. These are default values that the nested actions will probably want to change:
  • eth.src unchanged
  • eth.dst unchanged
  • eth.type = 0x0806
  • arp.op = 1 (ARP request)
  • arp.sha copied from eth.src
  • arp.spa copied from ip4.src
  • arp.tha = 00:00:00:00:00:00
  • arp.tpa copied from ip4.dst
The ARP packet has the same VLAN header, if any, as the IP packet it replaces.
Prerequisite: ip4
Parameters: logical port string field P, 32-bit IP address field A.
Looks up A in P’s mac binding table. If an entry is found, stores its Ethernet address in eth.dst, otherwise stores 00:00:00:00:00:00 in eth.dst.
Example: get_arp(outport, ip4.dst);
Parameters: logical port string field P, 32-bit IP address field A, 48-bit Ethernet address field E.
Adds or updates the entry for IP address A in logical port P’s mac binding table, setting its Ethernet address to E.
Example: put_arp(inport, arp.spa, arp.sha);
Parameters: logical port string field P, 32-bit IP address field A, 48-bit MAC address field M.
Result: stored to a 1-bit subfield R.
Looks up A and M in P’s mac binding table. If an entry is found, stores 1 in the 1-bit subfield R, else 0.
Example: reg0[0] = lookup_arp(inport, arp.spa, arp.sha);
Parameters: logical port string field P, 32-bit IP address field A.
Result: stored to a 1-bit subfield R.
Looks up A in P’s mac binding table. If an entry is found, stores 1 in the 1-bit subfield R, else 0.
Example: reg0[0] = lookup_arp_ip(inport, arp.spa);
Parameters:48-bit MAC address field A.
Looks up A in fdb table. If an entry is found, stores the logical port key to the out parameter P.
Example: outport = get_fdb(eth.src);
Parameters: logical port string field P, 48-bit MAC address field A.
Adds or updates the entry for Ethernet address A in fdb table, setting its logical port key to P.
Example: put_fdb(inport, arp.spa);
Parameters: 48-bit MAC address field M, logical port string field P.
Result: stored to a 1-bit subfield R.
Looks up A in fdb table. If an entry is found and the the logical port key is P, P, stores 1 in the 1-bit subfield R, else 0.
Example: reg0[0] = lookup_fdb(inport, eth.src);
Temporarily replaces the IPv6 packet being processed by an IPv6 Neighbor Solicitation packet and executes each nested action on the IPv6 NS packet. Actions following the nd_ns action, if any, apply to the original, unmodified packet.
The IPv6 NS packet that this action operates on is initialized based on the IPv6 packet being processed, as follows. These are default values that the nested actions will probably want to change:
  • eth.src unchanged
  • eth.dst set to IPv6 multicast MAC address
  • eth.type = 0x86dd
  • ip6.src copied from ip6.src
  • ip6.dst set to IPv6 Solicited-Node multicast address
  • icmp6.type = 135 (Neighbor Solicitation)
  • nd.target copied from ip6.dst
The IPv6 NS packet has the same VLAN header, if any, as the IP packet it replaces.
Prerequisite: ip6
Temporarily replaces the IPv6 neighbor solicitation packet being processed by an IPv6 neighbor advertisement (NA) packet and executes each nested action on the NA packet. Actions following the nd_na action, if any, apply to the original, unmodified packet.
The NA packet that this action operates on is initialized based on the IPv6 packet being processed, as follows. These are default values that the nested actions will probably want to change:
  • eth.dst exchanged with eth.src
  • eth.type = 0x86dd
  • ip6.dst copied from ip6.src
  • ip6.src copied from nd.target
  • icmp6.type = 136 (Neighbor Advertisement)
  • nd.target unchanged
  • nd.sll = 00:00:00:00:00:00
  • nd.tll copied from eth.dst
The ND packet has the same VLAN header, if any, as the IPv6 packet it replaces.
Prerequisite: nd_ns
Temporarily replaces the IPv6 neighbor solicitation packet being processed by an IPv6 neighbor advertisement (NA) packet, sets ND_NSO_ROUTER in the RSO flags and executes each nested action on the NA packet. Actions following the nd_na_router action, if any, apply to the original, unmodified packet.
The NA packet that this action operates on is initialized based on the IPv6 packet being processed, as follows. These are default values that the nested actions will probably want to change:
  • eth.dst exchanged with eth.src
  • eth.type = 0x86dd
  • ip6.dst copied from ip6.src
  • ip6.src copied from nd.target
  • icmp6.type = 136 (Neighbor Advertisement)
  • nd.target unchanged
  • nd.sll = 00:00:00:00:00:00
  • nd.tll copied from eth.dst
The ND packet has the same VLAN header, if any, as the IPv6 packet it replaces.
Prerequisite: nd_ns
Parameters: logical port string field P, 128-bit IPv6 address field A.
Looks up A in P’s mac binding table. If an entry is found, stores its Ethernet address in eth.dst, otherwise stores 00:00:00:00:00:00 in eth.dst.
Example: get_nd(outport, ip6.dst);
Parameters: logical port string field P, 128-bit IPv6 address field A, 48-bit Ethernet address field E.
Adds or updates the entry for IPv6 address A in logical port P’s mac binding table, setting its Ethernet address to E.
Example: put_nd(inport, nd.target, nd.tll);
Parameters: logical port string field P, 128-bit IP address field A, 48-bit MAC address field M.
Result: stored to a 1-bit subfield R.
Looks up A and M in P’s mac binding table. If an entry is found, stores 1 in the 1-bit subfield R, else 0.
Example: reg0[0] = lookup_nd(inport, ip6.src, eth.src);
Parameters: logical port string field P, 128-bit IP address field A.
Result: stored to a 1-bit subfield R.
Looks up A in P’s mac binding table. If an entry is found, stores 1 in the 1-bit subfield R, else 0.
Example: reg0[0] = lookup_nd_ip(inport, ip6.src);
Parameters: one or more DHCP option/value pairs, which must include an offerip option (with code 0).
Result: stored to a 1-bit subfield R.
Valid only in the ingress pipeline.
When this action is applied to a DHCP request packet (DHCPDISCOVER or DHCPREQUEST), it changes the packet into a DHCP reply (DHCPOFFER or DHCPACK, respectively), replaces the options by those specified as parameters, and stores 1 in R.
When this action is applied to a non-DHCP packet or a DHCP packet that is not DHCPDISCOVER or DHCPREQUEST, it leaves the packet unchanged and stores 0 in R.
The contents of the DHCP_Option table control the DHCP option names and values that this action supports.
Example: reg0[0] = put_dhcp_opts(offerip = 10.0.0.2, router = 10.0.0.1, netmask = 255.255.255.0, dns_server = {8.8.8.8, 7.7.7.7});
Parameters: one or more DHCPv6 option/value pairs.
Result: stored to a 1-bit subfield R.
Valid only in the ingress pipeline.
When this action is applied to a DHCPv6 request packet, it changes the packet into a DHCPv6 reply, replaces the options by those specified as parameters, and stores 1 in R.
When this action is applied to a non-DHCPv6 packet or an invalid DHCPv6 request packet , it leaves the packet unchanged and stores 0 in R.
The contents of the DHCPv6_Options table control the DHCPv6 option names and values that this action supports.
Example: reg0[3] = put_dhcpv6_opts(ia_addr = aef0::4, server_id = 00:00:00:00:10:02, dns_server={ae70::1,ae70::2});
Parameters: Queue number queue_number, in the range 0 to 61440.
This is a logical equivalent of the OpenFlow set_queue action. It affects packets that egress a hypervisor through a physical interface. For nonzero queue_number, it configures packet queuing to match the settings configured for the Port_Binding with options:qdisc_queue_id matching queue_number. When queue_number is zero, it resets queuing to the default strategy.
Example: set_queue(10);

With arguments, ct_lb commits the packet to the connection tracking table and DNATs the packet’s destination IP address (and port) to the IP address or addresses (and optional ports) specified in the backends. If multiple comma-separated IP addresses are specified, each is given equal weight for picking the DNAT address. By default, dp_hash is used as the OpenFlow group selection method, but if hash_fields is specified, hash is used as the selection method, and the fields listed are used as the hash fields. The ct_flag field represents one of supported flag: skip_snat or force_snat, this flag will be stored in ct_label register.
Without arguments, ct_lb sends the packet to the connection tracking table to NAT the packets. If the packet is part of an established connection that was previously committed to the connection tracker via ct_lb(...), it will automatically get DNATed to the same IP address as the first packet in that connection.
Processing automatically moves on to the next table, as if next; were specified, and later tables act on the packet as modified by the connection tracker. Connection tracking state is scoped by the logical port when the action is used in a flow for a logical switch, so overlapping addresses may be used. Connection tracking state is scoped by the logical topology when the action is used in a flow for a router.

Same as ct_lb, except that it internally uses ct_mark to store the NAT flag, while ct_lb uses ct_label for the same purpose.
Parameters: No parameters.
Result: stored to a 1-bit subfield R.
Valid only in the ingress pipeline.
When this action is applied to a valid DNS request (a UDP packet typically directed to port 53), it attempts to resolve the query using the contents of the DNS table. If it is successful, it changes the packet into a DNS reply and stores 1 in R. If the action is applied to a non-DNS packet, an invalid DNS request packet, or a valid DNS request for which the DNS table does not supply an answer, it leaves the packet unchanged and stores 0 in R.
Regardless of success, the action does not make any of the changes to the flow that are necessary to direct the packet back to the requester. The logical pipeline can implement this behavior with matches and actions in later tables.
Example: reg0[3] = dns_lookup();
Prerequisite: udp
Parameters: The following IPv6 ND Router Advertisement option/value pairs as defined in RFC 4861.
•
addr_mode
Mandatory parameter which specifies the address mode flag to be set in the RA flag options field. The value of this option is a string and the following values can be defined - "slaac", "dhcpv6_stateful" and "dhcpv6_stateless".
•
slla
Mandatory parameter which specifies the link-layer address of the interface from which the Router Advertisement is sent.
•
mtu
Optional parameter which specifies the MTU.
•
prefix
Optional parameter which should be specified if the addr_mode is "slaac" or "dhcpv6_stateless". The value should be an IPv6 prefix which will be used for stateless IPv6 address configuration. This option can be defined multiple times.
Result: stored to a 1-bit subfield R.
Valid only in the ingress pipeline.
When this action is applied to an IPv6 Router solicitation request packet, it changes the packet into an IPv6 Router Advertisement reply and adds the options specified in the parameters, and stores 1 in R.
When this action is applied to a non-IPv6 Router solicitation packet or an invalid IPv6 request packet , it leaves the packet unchanged and stores 0 in R.
Example: reg0[3] = put_nd_ra_opts(addr_mode = "slaac", slla = 00:00:00:00:10:02, prefix = aef0::/64, mtu = 1450);

Parameters: rate limit int field rate in kbps, burst rate limits int field burst in kbps.
This action sets the rate limit for a flow.
Example: set_meter(100, 1000);
Parameters: packet length L to check for in bytes.
Result: stored to a 1-bit subfield R.
This is a logical equivalent of the OpenFlow check_pkt_larger action. If the packet is larger than the length specified in L, it stores 1 in the subfield R.
Example: reg0[6] = check_pkt_larger(1000);
Causes ovn-controller to log the packet on the chassis that processes it. Packet logging currently uses the same logging mechanism as other Open vSwitch and OVN messages, which means that whether and where log messages appear depends on the local logging configuration that can be configured with ovs-appctl, etc.
The log action takes zero or more of the following key-value pair arguments that control what is logged:
An optional name for the ACL. The string is currently limited to 64 bytes.
Indicates the severity of the event. The level is one of following (from more to less serious): alert, warning, notice, info, or debug. If a severity is not provided, the default is info.
The verdict for packets matching the flow. The value must be one of allow, deny, or reject.
An optional rate-limiting meter to be applied to the logs. The string should reference a name entry from the Meter table. The only meter action that is appropriate is drop.
Parameters: optional liveness, either true or false, defaulting to false; childports, a comma-delimited list of strings denoting logical ports to load balance across.
Load balance traffic to one or more child ports in a logical switch. ovn-controller translates the fwd_group into an OpenFlow group with one bucket for each child port. If liveness=true is specified, it also integrates the bucket selection with BFD status on the tunnel interface corresponding to child port.
Example: fwd_group(liveness=true, childports="p1", "p2");

Temporarily replaces the IPv4 packet being processed by an ICMPv4 packet and executes each nested action on the ICMPv4 packet. Actions following these actions, if any, apply to the original, unmodified packet.
The ICMPv4 packet that these actions operates on is initialized based on the IPv4 packet being processed, as follows. These are default values that the nested actions will probably want to change. Ethernet and IPv4 fields not listed here are not changed:
  • ip.proto = 1 (ICMPv4)
  • ip.frag = 0 (not a fragment)
  • ip.ttl = 255
  • icmp4.type = 3 (destination unreachable)
  • icmp4.code = 1 (host unreachable)
icmp4_error action is expected to be used to generate an ICMPv4 packet in response to an error in original IP packet. When this action generates the ICMPv4 packet, it also copies the original IP datagram following the ICMPv4 header as per RFC 1122: 3.2.2.
Prerequisite: ip4

Temporarily replaces the IPv6 packet being processed by an ICMPv6 packet and executes each nested action on the ICMPv6 packet. Actions following the icmp6 action, if any, apply to the original, unmodified packet.
The ICMPv6 packet that this action operates on is initialized based on the IPv6 packet being processed, as follows. These are default values that the nested actions will probably want to change. Ethernet and IPv6 fields not listed here are not changed:
  • ip.proto = 58 (ICMPv6)
  • ip.ttl = 255
  • icmp6.type = 1 (destination unreachable)
  • icmp6.code = 1 (administratively prohibited)
icmp6_error action is expected to be used to generate an ICMPv6 packet in response to an error in original IPv6 packet.
Prerequisite: ip6
This action transforms the current TCP packet according to the following pseudocode:



if (tcp.ack) {


        tcp.seq = tcp.ack;


} else {


        tcp.ack = tcp.seq + length(tcp.payload);


        tcp.seq = 0;


}


tcp.flags = RST;
Then, the action drops all TCP options and payload data, and updates the TCP checksum. IP ttl is set to 255.
Prerequisite: tcp
If the original packet is IPv4 or IPv6 TCP packet, it replaces it with IPv4 or IPv6 TCP RST packet and executes the inner actions. Otherwise it replaces it with an ICMPv4 or ICMPv6 packet and executes the inner actions.
The inner actions should not attempt to swap eth source with eth destination and IP source with IP destination as this action implicitly does that.
This action is used to allow ovs-vswitchd to report CMS related events writing them in Controller_Event table. It is possible to associate a meter to a each event in order to not overload pinctrl thread under heavy load; each meter is identified though a defined naming convention. Supported events:
•
empty_lb_backends. This event is raised if a received packet is destined for a load balancer VIP that has no configured backend destinations. For this event, the event info includes the load balancer VIP, the load balancer UUID, and the transport protocol. Associated meter: event-elb
This action sends the packet to ovn-controller for multicast snooping.
Prerequisite: igmp
Parameters: logical port string field V of type virtual, logical port string field P.
Binds the virtual logical port V and sets the chassis column and virtual_parent of the table Port_Binding. virtual_parent is set to P.
Parameters: logical port string field P.
Handles the service monitor reply received from the VIF of the logical port P. ovn-controller periodically sends out the service monitor packets for the services configured in the Service_Monitor table and this action updates the status of those services.
Example: handle_svc_check(inport);
Handle DHCPv6 prefix delegation advertisements/replies from a IPv6 delegation server. ovn-controller will add an entry ipv6_ra_pd_list in the options table for each prefix received from the delegation server
Parameters: Integer N1, N2..., with optional weight W1, W2, ...
Result: stored to a logical field or subfield R.
Select from a list of integers N1, N2..., each within the range 0 ~ 65535, and store the selected one in the field R. There must be 2 or more integers listed, each with an optional weight, which is an integer within the range 1 ~ 65535. If weight is not specified, it defaults to 100. The selection method is based on the 5-tuple hash of packet header.
Processing automatically moves on to the next table, as if next; were specified. The select action must be put as the last action of the logical flow when there are multiple actions (actions put after select will not take effect).
Example: reg8[16..31] = select(1=20, 2=30, 3=50);
This action is used to parse DHCPv6 replies from IPv6 Delegation Router and managed IPv6 Prefix delegation state machine
This action checks if the packet under consideration was destined to a load balancer VIP and it is hairpinned, i.e., after load balancing the destination IP matches the source IP. If it is so, then the 1-bit destination register R is set to 1.
This action checks if the packet under consideration is from one of the backend IP of a load balancer VIP and the destination IP is the load balancer VIP. If it is so, then the 1-bit destination register R is set to 1.
This action sends the packet through the SNAT zone to change the source IP address of the packet to the load balancer VIP if the original destination IP was load balancer VIP and commits the connection. This action applies successfully only for the hairpinned traffic i.e if the action chk_lb_hairpin returned success. This action doesn’t take any arguments and it determines the SNAT IP internally. The packet is not automatically sent to the next table. The caller has to execute the next; action explicitly after this action to advance the packet to the next stage.
This action checks if the packet under consideration passes the inport port security checks. If the packet fails the port security checks, then 1 is stored in the destination register R. Else 0 is stored. The port security values to check are retrieved from the the inport logical port.
This action should be used in the ingress logical switch pipeline.
Example: reg8[0..7] = check_in_port_sec();
This action checks if the packet under consideration passes the outport port security checks. If the packet fails the port security checks, then 1 is stored in the destination register R. Else 0 is stored. The port security values to check are retrieved from the the outport logical port.
This action should be used in the egress logical switch pipeline.
Example: reg8[0..7] = check_out_port_sec();
Parameters: IPv4/IPv6 traffic.
This action translates to an openflow "learn" action that inserts two new flows in tables 76 and 77.
  • Match on the the 5-tuple and the expected next-hop mac address in table 76: nw_src=ip0, nw_dst=ip1, ip_proto,tp_src=l4_port0, tp_dst=l4_port1,dl_src=ethaddr and set reg9[5].
  • Match on the 5-tuple in table 77: nw_src=ip1, nw_dst=ip0, ip_proto, tp_src=l4_port1, tp_dst=l4_port0 and set reg9[5] to 1
This action is applied if the packet arrives via ECMP route or if it is routed via an ECMP route
This action checks if the packet under consideration matches any flow in table 76. If it is so, then the 1-bit destination register R is set to 1.
This action checks if the packet under consideration matches the any flow in table 77. If it is so, then the 1-bit destination register R is set to 1.
commit_lb_aff(vip, backend, proto, timeout); Parameters: load-balancer virtual ip:port vip, load-balancer backend ip:port backend, load-balancer protocol proto, affinity timeout timeout.
This action translates to an openflow "learn" action that inserts a new flow in table 78.
•
Match on the 4-tuple in table 78: nw_src=ip client, nw_dst=vip ip, ip_proto, tp_dst=vip port and set reg9[6] to 1, reg4 and reg8 to backend ip and port respectively. For IPv6 register xxreg1 is used to store the backend ip.
This action is applied for new connections received by a specific load-balacer with affinity timeout configured.
This action checks if the packet under consideration matches any flow in table 78. If it is so, then the 1-bit destination register R is set to 1.
This action causes the matched traffic to be sampled using IPFIX protocol. More information about how per-flow IPFIX sampling works in OVS can be found in ovs-actions(7) and ovs-vswitchd.conf.db(5).
In order to reliably identify each sampled packet when it is received by the IPFIX collector, this action sets the content of the ObservationDomainID and ObservationPointID IPFIX fields (see argument description below).
The following key-value arguments are supported:
The number of sampled packets out of 65535. It must be greater or equal to 1.
The unsigned 32-bit integer identifier of the sample collector to send sampled packets to. It must match the value configured in the Flow_Sample_Collector_Set Table in OVS. Defaults to 0.
An unsigned 8-bit integer that identifies the sampling application. It will be placed in the 8 most significant bits of the ObservationDomainID field of IPFIX samples. The 24 less significant bits will be automatically filled in with the datapath key. Defaults to 0.
An unsigned 32-bit integer to be used as ObsservationPointID or the string @cookie to indicate that the first 32 bits of the Logical_Flow’s UUID shall be used instead.
Key-value pairs that provide additional information to help ovn-controller processing the logical flow. Below are the tags used by ovn-controller.
In the logical flow’s "match" column, if a logical port P is compared with "inport" and the logical flow is on a logical switch ingress pipeline, or if P is compared with "outport" and the logical flow is on a logical switch egress pipeline, and the expression is combined with other expressions (if any) using the operator &&, then the port P should be added as the value in this tag. If there are multiple logical ports meeting this criteria, one of them can be added. ovn-controller uses this information to skip parsing flows that are not needed on the chassis. Failing to add the tag will affect efficiency, while adding wrong value will affect correctness.
The name of the meter in table Meter to be used for all packets that the logical flow might send to ovn-controller.
Human-readable name for this flow’s stage in the pipeline.
UUID of a OVN_Northbound record that caused this logical flow to be created. Currently used only for attribute of logical flows to northbound ACL records.
Source file and line number of the code that added this flow to the pipeline.

Common Columns:

The overall purpose of these columns is described under Common Columns at the beginning of this document.

Each row in this table represents a group of logical datapaths referenced by the logical_dp_group column in the Logical_Flow table.

set of weak reference to Datapath_Bindings

List of Datapath_Binding entries.

The rows in this table define multicast groups of logical ports. Multicast groups allow a single packet transmitted over a tunnel to a hypervisor to be delivered to multiple VMs on that hypervisor, which uses bandwidth more efficiently.

Each row in this table defines a logical multicast group numbered tunnel_key within datapath, whose logical ports are listed in the ports column.

Datapath_Binding
integer, in range 32,768 to 65,535
string
set of weak reference to Port_Bindings

The logical datapath in which the multicast group resides.
The value used to designate this logical egress port in tunnel encapsulations. An index forces the key to be unique within the datapath. The unusual range ensures that multicast group IDs do not overlap with logical port IDs.
The logical multicast group’s name. An index forces the name to be unique within the datapath. Logical flows in the ingress pipeline may output to the group just as for individual logical ports, by assigning the group’s name to outport and executing an output action.
Multicast group names and logical port names share a single namespace and thus should not overlap (but the database schema cannot enforce this). To try to avoid conflicts, ovn-northd uses names that begin with _MC_.
The logical ports included in the multicast group. All of these ports must be in the datapath logical datapath (but the database schema cannot enforce this).

Each row in this table represents a mirror that can be used for port mirroring. These mirrors are referenced by the mirror_rules column in the Port_Binding table.

string (must be unique within table)
string, either from-lport or to-lport
string
string, either erspan or gre
integer
map of string-string pairs

Represents the name of the mirror.
The value of this field represents selection criteria of the mirror.
The value of this field represents the destination/sink of the mirror.
The value of this field represents the type of the tunnel used for sending the mirrored packets
The value of this field represents the key/idx depending on the tunnel type configured
See External IDs at the beginning of this document.

Each row in this table represents a meter that can be used for QoS or rate-limiting.

string (must be unique within table)
string, either kbps or pktps
set of 1 or more Meter_Bands

A name for this meter.
Names that begin with "__" (two underscores) are reserved for OVN internal use and should not be added manually.
The unit for rate and burst_rate parameters in the bands entry. kbps specifies kilobits per second, and pktps specifies packets per second.
The bands associated with this meter. Each band specifies a rate above which the band is to take the action action. If multiple bands’ rates are exceeded, then the band with the highest rate among the exceeded bands is selected.

Each row in this table represents a meter band which specifies the rate above which the configured action should be applied. These bands are referenced by the bands column in the Meter table.

string, must be drop
integer, in range 1 to 4,294,967,295
integer, in range 0 to 4,294,967,295

The action to execute when this band matches. The only supported action is drop.
The rate limit for this band, in kilobits per second or bits per second, depending on whether the parent Meter entry’s unit column specified kbps or pktps.
The maximum burst allowed for the band in kilobits or packets, depending on whether kbps or pktps was selected in the parent Meter entry’s unit column. If the size is zero, the switch is free to select some reasonable value depending on its configuration.

Each row in this table represents a logical datapath, which implements a logical pipeline among the ports in the Port_Binding table associated with it. In practice, the pipeline in a given logical datapath implements either a logical switch or a logical router.

The main purpose of a row in this table is provide a physical binding for a logical datapath. A logical datapath does not have a physical location, so its physical binding information is limited: just tunnel_key. The rest of the data in this table does not affect packet forwarding.

integer, in range 1 to 16,777,215 (must be unique within table)
set of uuids

optional string, containing an uuid
optional string, containing an uuid
optional string

optional string
optional string


map of string-string pairs

The tunnel key value to which the logical datapath is bound. The Tunnel Encapsulation section in ovn-architecture(7) describes how tunnel keys are constructed for each supported encapsulation.
Not used anymore; kept for backwards compatibility of the schema.

OVN_Northbound Relationship:

Each row in Datapath_Binding is associated with some logical datapath. ovn-northd uses these keys to track the association of a logical datapath with concepts in the OVN_Northbound database.

For a logical datapath that represents a logical switch, ovn-northd stores in this key the UUID of the corresponding Logical_Switch row in the OVN_Northbound database.
For a logical datapath that represents a logical router, ovn-northd stores in this key the UUID of the corresponding Logical_Router row in the OVN_Northbound database.
For a logical datapath that represents a logical switch that represents a transit switch for interconnection, ovn-northd stores in this key the value of the same interconn-ts key of the external_ids column of the corresponding Logical_Switch row in the OVN_Northbound database.

Naming:

ovn-northd copies these from the name fields in the OVN_Northbound database, either from name and external_ids:neutron:router_name in the Logical_Router table or from name and external_ids:neutron:network_name in the Logical_Switch table.

A name for the logical datapath.
Another name for the logical datapath.

Common Columns:

The overall purpose of these columns is described under Common Columns at the beginning of this document.

Each row in this table binds a logical port to a realization. For most logical ports, this means binding to some physical location, for example by binding a logical port to a VIF that belongs to a VM running on a particular hypervisor. Other logical ports, such as logical patch ports, can be realized without a specific physical location, but their bindings are still expressed through rows in this table.

For every Logical_Switch_Port record in OVN_Northbound database, ovn-northd creates a record in this table. ovn-northd populates and maintains every column except the chassis and virtual_parent columns, which it leaves empty in new records.

ovn-controller/ovn-controller-vtep populates the chassis column for the records that identify the logical ports that are located on its hypervisor/gateway, which ovn-controller/ovn-controller-vtep in turn finds out by monitoring the local hypervisor’s Open_vSwitch database, which identifies logical ports via the conventions described in IntegrationGuide.rst. (The exceptions are for Port_Binding records with type of l3gateway, whose locations are identified by ovn-northd via the options:l3gateway-chassis column in this table. ovn-controller is still responsible to populate the chassis column.)

ovn-controller also populates the virtual_parent column of records whose type is virtual.

When a chassis shuts down gracefully, it should clean up the chassis column that it previously had populated. (This is not critical because resources hosted on the chassis are equally unreachable regardless of whether their rows are present.) To handle the case where a VM is shut down abruptly on one chassis, then brought up again on a different one, ovn-controller/ovn-controller-vtep must overwrite the chassis column with new information.


Datapath_Binding
string (must be unique within table)
optional weak reference to Encap
set of weak reference to Encaps
optional weak reference to Chassis
set of weak reference to Chassis
set of Gateway_Chassises
optional HA_Chassis_Group
optional boolean
integer, in range 1 to 32,767
set of strings
set of strings
string
optional weak reference to Chassis
set of weak reference to Chassis

set of weak reference to Mirrors

optional string
set of strings


optional string
optional string
set of strings


optional string
optional integer, in range 1 to 4,095


optional string
optional string
optional integer, in range 1 to 4,095


optional string
optional string


optional string
optional string
optional string
optional string
optional string
optional string
optional string
optional string, containing an integer, in range 1 to 61,440


optional string


optional string
optional string
optional string


optional string
optional integer, in range 1 to 4,095


optional string


optional string


map of string-string pairs

Core Features:
The logical datapath to which the logical port belongs.
A logical port. For a logical switch port, this is taken from name in the OVN_Northbound database’s Logical_Switch_Port table. For a logical router port, this is taken from name in the OVN_Northbound database’s Logical_Router_port table. (This means that logical switch ports and router port names must not share names in an OVN deployment.) OVN does not prescribe a particular format for the logical port ID.
Points to preferred encapsulation configuration to transmit logical dataplane packets to this chassis. The entry is reference to a Encap record.
Points to preferred encapsulation configuration to transmit logical dataplane packets to this additional chassis. The entry is reference to a Encap record. See also additional_chassis.
The meaning of this column depends on the value of the type column. This is the meaning for each type
(empty string)
The physical location of the logical port. To successfully identify a chassis, this column must be a Chassis record. This is populated by ovn-controller.
The physical location of the hardware_vtep gateway. To successfully identify a chassis, this column must be a Chassis record. This is populated by ovn-controller-vtep.
Always empty. A localnet port is realized on every chassis that has connectivity to the corresponding physical network.
Always empty. A localport port is present on every chassis.
The physical location of the L3 gateway. To successfully identify a chassis, this column must be a Chassis record. This is populated by ovn-controller based on the value of the options:l3gateway-chassis column in this table.
The physical location of this L2 gateway. To successfully identify a chassis, this column must be a Chassis record. This is populated by ovn-controller based on the value of the options:l2gateway-chassis column in this table.
The meaning of this column is the same as for the chassis. The column is used to track an additional physical location of the logical port. Used with regular (empty type) port bindings.
A list of Gateway_Chassis.
This should only be populated for ports with type set to chassisredirect. This column defines the list of chassis used as gateways where traffic will be redirected through.
This should only be populated for ports with type set to chassisredirect. This column defines the HA chassis group with a list of HA chassis used as gateways where traffic will be redirected through.
This is set to true whenever all OVS flows required by this Port_Binding have been installed. This is populated by ovn-controller.
A number that represents the logical port in the key (e.g. STT key or Geneve TLV) field carried within tunnel protocol packets.
The tunnel ID must be unique within the scope of a logical datapath.
This column is a misnomer as it may contain MAC addresses and IP addresses. It is copied from the addresses column in the Logical_Switch_Port table in the Northbound database. It follows the same format as that column.
This column controls the addresses from which the host attached to the logical port (``the host’’) is allowed to send packets and to which it is allowed to receive packets. If this column is empty, all addresses are permitted.
It is copied from the port_security column in the Logical_Switch_Port table in the Northbound database. It follows the same format as that column.
A type for this logical port. Logical ports can be used to model other types of connectivity into an OVN logical switch. The following types are defined:
(empty string)
VM (or VIF) interface.
One of a pair of logical ports that act as if connected by a patch cable. Useful for connecting two logical datapaths, e.g. to connect a logical router to a logical switch or to another logical router.
l3gateway
One of a pair of logical ports that act as if connected by a patch cable across multiple chassis. Useful for connecting a logical switch with a Gateway router (which is only resident on a particular chassis).
localnet
A connection to a locally accessible network from ovn-controller instances that have a corresponding bridge mapping. A logical switch can have multiple localnet ports attached. This type is used to model direct connectivity to existing networks. In this case, each chassis should have a mapping for one of the physical networks only. Note: nothing said above implies that a chassis cannot be plugged to multiple physical networks as long as they belong to different switches.
localport
A connection to a local VIF. Traffic that arrives on a localport is never forwarded over a tunnel to another chassis. These ports are present on every chassis and have the same address in all of them. This is used to model connectivity to local services that run on every hypervisor.
l2gateway
An L2 connection to a physical network. The chassis this Port_Binding is bound to will serve as an L2 gateway to the network named by options:network_name.
vtep
A port to a logical switch on a VTEP gateway chassis. In order to get this port correctly recognized by the OVN controller, the options:vtep-physical-switch and options:vtep-logical-switch must also be defined.
A logical port that represents a particular instance, bound to a specific chassis, of an otherwise distributed parent port (e.g. of type patch). A chassisredirect port should never be used as an inport. When an ingress pipeline sets the outport, it may set the value to a logical port of type chassisredirect. This will cause the packet to be directed to a specific chassis to carry out the egress pipeline. At the beginning of the egress pipeline, the outport will be reset to the value of the distributed port.
Represents a logical port with an virtual ip. This virtual ip can be configured on a logical port (which is referred as virtual parent).
This column exists so that the ovn-controller can effectively monitor all Port_Binding records destined for it, and is a supplement to the options:requested-chassis option. The option is still required so that the ovn-controller can check the CMS intent when the chassis pointed to does not currently exist, which for example occurs when the ovn-controller is stopped without passing the -restart argument. This column must be a Chassis record. This is populated by ovn-northd when the options:requested-chassis is defined and contains a string matching the name or hostname of an existing chassis. See also requested_additional_chassis.
This column exists so that the ovn-controller can effectively monitor all Port_Binding records destined for it, and is a supplement to the options:requested-chassis option when multiple chassis are listed. This column must be a list of Chassis records. This is populated by ovn-northd when the options:requested-chassis is defined as a list of chassis names or hostnames. See also requested_chassis.
Mirror rules that apply to the port binding. Please see the Mirror table.

Patch Options:

These options apply to logical ports with type of patch.

The logical_port in the Port_Binding record for the other side of the patch. The named logical_port must specify this logical_port in its own peer option. That is, the two patch logical ports must have reversed logical_port and peer values.
MAC address followed by a list of SNAT and DNAT external IP addresses, followed by is_chassis_resident("lport"), where lport is the name of a logical port on the same chassis where the corresponding NAT rules are applied. This is used to send gratuitous ARPs for SNAT and DNAT external IP addresses via localnet, from the chassis where lport resides. Example: 80:fa:5b:06:72:b7 158.36.44.22 158.36.44.24 is_chassis_resident("foo1"). This would result in generation of gratuitous ARPs for IP addresses 158.36.44.22 and 158.36.44.24 with a MAC address of 80:fa:5b:06:72:b7 from the chassis where the logical port "foo1" resides.

L3 Gateway Options:

These options apply to logical ports with type of l3gateway.

The logical_port in the Port_Binding record for the other side of the ’l3gateway’ port. The named logical_port must specify this logical_port in its own peer option. That is, the two ’l3gateway’ logical ports must have reversed logical_port and peer values.
The chassis in which the port resides.
MAC address of the l3gateway port followed by a list of SNAT and DNAT external IP addresses. This is used to send gratuitous ARPs for SNAT and DNAT external IP addresses via localnet. Example: 80:fa:5b:06:72:b7 158.36.44.22 158.36.44.24. This would result in generation of gratuitous ARPs for IP addresses 158.36.44.22 and 158.36.44.24 with a MAC address of 80:fa:5b:06:72:b7. This is used in OVS version 2.8 and later versions.

Localnet Options:

These options apply to logical ports with type of localnet.

Required. ovn-controller uses the configuration entry ovn-bridge-mappings to determine how to connect to this network. ovn-bridge-mappings is a list of network names mapped to a local OVS bridge that provides access to that network. An example of configuring ovn-bridge-mappings would be: .IP 
$ ovs-vsctl set open . external-ids:ovn-bridge-mappings=physnet1:br-eth0,physnet2:br-eth1
When a logical switch has a localnet port attached, every chassis that may have a local vif attached to that logical switch must have a bridge mapping configured to reach that localnet. Traffic that arrives on a localnet port is never forwarded over a tunnel to another chassis. If there are multiple localnet ports in a logical switch, each chassis should only have a single bridge mapping for one of the physical networks. Note: In case of multiple localnet ports, to provide interconnectivity between all VIFs located on different chassis with different fabric connectivity, the fabric should implement some form of routing between the segments.
If set, indicates that the port represents a connection to a specific VLAN on a locally accessible network. The VLAN ID is used to match incoming traffic and is also added to outgoing traffic.

L2 Gateway Options:

These options apply to logical ports with type of l2gateway.

Required. ovn-controller uses the configuration entry ovn-bridge-mappings to determine how to connect to this network. ovn-bridge-mappings is a list of network names mapped to a local OVS bridge that provides access to that network. An example of configuring ovn-bridge-mappings would be: .IP 
$ ovs-vsctl set open . external-ids:ovn-bridge-mappings=physnet1:br-eth0,physnet2:br-eth1
When a logical switch has a l2gateway port attached, the chassis that the l2gateway port is bound to must have a bridge mapping configured to reach the network identified by network_name.
Required. The chassis in which the port resides.
If set, indicates that the gateway is connected to a specific VLAN on the physical network. The VLAN ID is used to match incoming traffic and is also added to outgoing traffic.

VTEP Options:

These options apply to logical ports with type of vtep.

Required. The name of the VTEP gateway.
Required. A logical switch name connected by the VTEP gateway. Must be set when type is vtep.

VMI (or VIF) Options:

These options apply to logical ports with type having (empty string)

If set, identifies a specific chassis (by name or hostname) that is allowed to bind this port. Using this option will prevent thrashing between two chassis trying to bind the same port during a live migration. It can also prevent similar thrashing due to a mis-configuration, if a port is accidentally created on more than one chassis.
If set to a comma separated list, the first entry identifies the main chassis and the rest are one or more additional chassis that are allowed to bind the same port.
When multiple chassis are set for the port, and the logical switch is connected to an external network through a localnet port, tunneling is enforced for the port to guarantee delivery of packets directed to the port to all its locations. This has MTU implications because the network used for tunneling must have MTU larger than localnet for stable connectivity.
If used with multiple chassis set in requested-chassis, specifies an activation strategy for all additional chassis. By default, no activation strategy is used, meaning additional port locations are immediately available for use. When set to "rarp", the port is blocked for ingress and egress communication until a RARP packet is sent from a new location. The "rarp" strategy is useful in live migration scenarios for virtual machines.
When activation-strategy is set, this option indicates that the port was activated using the strategy specified.
If set, this port will be bound by ovn-controller only if this same key and value is configured in the external_ids column in the Open_vSwitch database’s Interface table.
If set, indicates the minimum guaranteed rate available for data sent from this interface, in bit/s.
If set, indicates the maximum rate for data sent from this interface, in bit/s. The traffic will be shaped according to this limit.
If set, indicates the maximum burst size for data sent from this interface, in bits.
Indicates the queue number on the physical device. This is same as the queue_id used in OpenFlow in struct ofp_action_enqueue.

Distributed Gateway Port Options:

These options apply to the distributed parent ports of logical ports with type of chasssisredirect.

The name of the chassis redirect port derived from this port if this port is a distributed parent of a chassis redirect port.

Chassis Redirect Options:

These options apply to logical ports with type of chassisredirect.

The name of the distributed port for which this chassisredirect port represents a particular instance.
The value is copied from the column options in the OVN_Northbound database’s Logical_Router_Port table for the distributed parent of this port.
A boolean option that is set to true if the distributed parent of this chassis redirect port does not need distributed processing.

Nested Containers:

These columns support containers nested within a VM. Specifically, they are used when type is empty and logical_port identifies the interface of a container spawned inside a VM. They are empty for containers or VMs that run directly on a hypervisor.

This is taken from parent_name in the OVN_Northbound database’s Logical_Switch_Port table.
Identifies the VLAN tag in the network traffic associated with that container’s network interface.
This column is used for a different purpose when type is localnet (see Localnet Options, above) or l2gateway (see L2 Gateway Options, above).

Virtual ports:
This column is set by ovn-controller with one of the value from the options:virtual-parents in the OVN_Northbound database’s Logical_Switch_Port table when the OVN action bind_vport is executed. ovn-controller also sets the chassis column when it executes this action with its chassis id.
ovn-controller sets this column only if the type is "virtual".

Naming:
For a logical switch port, ovn-northd copies this from external_ids:neutron:port_name in the Logical_Switch_Port table in the OVN_Northbound database, if it is a nonempty string.
For a logical switch port, ovn-northd does not currently set this key.

Common Columns:
See External IDs at the beginning of this document.
The ovn-northd program populates this column with all entries into the external_ids column of the Logical_Switch_Port and Logical_Router_Port tables of the OVN_Northbound database.

Each row in this table specifies a binding from an IP address to an Ethernet address that has been discovered through ARP (for IPv4) or neighbor discovery (for IPv6). This table is primarily used to discover bindings on physical networks, because IP-to-MAC bindings for virtual machines are usually populated statically into the Port_Binding table.

This table expresses a functional relationship: MAC_Binding(logical_port, ip) = mac.

In outline, the lifetime of a logical router’s MAC binding looks like this:

1.
On hypervisor 1, a logical router determines that a packet should be forwarded to IP address A on one of its router ports. It uses its logical flow table to determine that A lacks a static IP-to-MAC binding and the get_arp action to determine that it lacks a dynamic IP-to-MAC binding.
2.
Using an OVN logical arp action, the logical router generates and sends a broadcast ARP request to the router port. It drops the IP packet.
3.
The logical switch attached to the router port delivers the ARP request to all of its ports. (It might make sense to deliver it only to ports that have no static IP-to-MAC bindings, but this could also be surprising behavior.)
4.
A host or VM on hypervisor 2 (which might be the same as hypervisor 1) attached to the logical switch owns the IP address in question. It composes an ARP reply and unicasts it to the logical router port’s Ethernet address.
5.
The logical switch delivers the ARP reply to the logical router port.
6.
The logical router flow table executes a put_arp action. To record the IP-to-MAC binding, ovn-controller adds a row to the MAC_Binding table.
7.
On hypervisor 1, ovn-controller receives the updated MAC_Binding table from the OVN southbound database. The next packet destined to A through the logical router is sent directly to the bound Ethernet address.

string
string
string
integer
Datapath_Binding

The logical port on which the binding was discovered.
The bound IP address.
The Ethernet address to which the IP is bound.
The timestamp in msec when the MAC binding was added or updated. Records that existed before this column will have 0.
The logical datapath to which the logical port belongs.

Each row in this table stores the DHCP Options supported by native OVN DHCP. ovn-northd populates this table with the supported DHCP options. ovn-controller looks up this table to get the DHCP codes of the DHCP options defined in the "put_dhcp_opts" action. Please refer to the RFC 2132 "https://tools.ietf.org/html/rfc2132" for the possible list of DHCP options that can be defined here.

string
integer, in range 0 to 254
string, one of bool, domains, host_id, ipv4, static_routes, str, uint16, uint32, or uint8

Name of the DHCP option.
Example. name="router"
DHCP option code for the DHCP option as defined in the RFC 2132.
Example. code=3
Data type of the DHCP option code.
This indicates that the value of the DHCP option is a bool.
Example. "name=ip_forward_enable", "code=19", "type=bool".
put_dhcp_opts(..., ip_forward_enable = 1,...)
This indicates that the value of the DHCP option is an unsigned int8 (8 bits)
Example. "name=default_ttl", "code=23", "type=uint8".
put_dhcp_opts(..., default_ttl = 50,...)
This indicates that the value of the DHCP option is an unsigned int16 (16 bits).
Example. "name=mtu", "code=26", "type=uint16".
put_dhcp_opts(..., mtu = 1450,...)
This indicates that the value of the DHCP option is an unsigned int32 (32 bits).
Example. "name=lease_time", "code=51", "type=uint32".
put_dhcp_opts(..., lease_time = 86400,...)
This indicates that the value of the DHCP option is an IPv4 address or addresses.
Example. "name=router", "code=3", "type=ipv4".
put_dhcp_opts(..., router = 10.0.0.1,...)
Example. "name=dns_server", "code=6", "type=ipv4".
put_dhcp_opts(..., dns_server = {8.8.8.8 7.7.7.7},...)
This indicates that the value of the DHCP option contains a pair of IPv4 route and next hop addresses.
Example. "name=classless_static_route", "code=121", "type=static_routes".
put_dhcp_opts(..., classless_static_route = {30.0.0.0/24,10.0.0.4,0.0.0.0/0,10.0.0.1}...)
This indicates that the value of the DHCP option is a string.
Example. "name=host_name", "code=12", "type=str".
This indicates that the value of the DHCP option is a host_id. It can either be a host_name or an IP address.
Example. "name=tftp_server", "code=66", "type=host_id".
This indicates that the value of the DHCP option is a domain name or a comma separated list of domain names.
Example. "name=domain_search_list", "code=119", "type=domains".

Each row in this table stores the DHCPv6 Options supported by native OVN DHCPv6. ovn-northd populates this table with the supported DHCPv6 options. ovn-controller looks up this table to get the DHCPv6 codes of the DHCPv6 options defined in the put_dhcpv6_opts action. Please refer to RFC 3315 and RFC 3646 for the list of DHCPv6 options that can be defined here.

string
integer, in range 0 to 254
string, one of ipv6, mac, or str

Name of the DHCPv6 option.
Example. name="ia_addr"
DHCPv6 option code for the DHCPv6 option as defined in the appropriate RFC.
Example. code=3
Data type of the DHCPv6 option code.
This indicates that the value of the DHCPv6 option is an IPv6 address(es).
Example. "name=ia_addr", "code=5", "type=ipv6".
put_dhcpv6_opts(..., ia_addr = ae70::4,...)
This indicates that the value of the DHCPv6 option is a string.
Example. "name=domain_search", "code=24", "type=str".
put_dhcpv6_opts(..., domain_search = ovn.domain,...)
This indicates that the value of the DHCPv6 option is a MAC address.
Example. "name=server_id", "code=2", "type=mac".
put_dhcpv6_opts(..., server_id = 01:02:03:04L05:06,...)

Configuration for a database connection to an Open vSwitch database (OVSDB) client.

This table primarily configures the Open vSwitch database server (ovsdb-server).

The Open vSwitch database server can initiate and maintain active connections to remote clients. It can also listen for database connections.


string (must be unique within table)
boolean
string


optional integer, at least 1,000
optional integer


boolean
optional string
optional string, one of ACTIVE, BACKOFF, CONNECTING, IDLE, or VOID
optional string, containing an integer, at least 0
optional string, containing an integer, at least 0
optional string
optional string
optional string
optional string, containing an integer, at least 2
optional string, containing an integer


map of string-string pairs
map of string-string pairs

Core Features:
Connection methods for clients.
The following connection methods are currently supported:
The specified SSL port on the given host, which can either be a DNS name (if built with unbound library) or an IP address. A valid SSL configuration must be provided when this form is used, this configuration can be specified via command-line options or the SSL table.
If port is not specified, it defaults to 6640.
SSL support is an optional feature that is not always built as part of Open vSwitch.
The specified TCP port on the given host, which can either be a DNS name (if built with unbound library) or an IP address (IPv4 or IPv6). If host is an IPv6 address, wrap it in square brackets, e.g. tcp:[::1]:6640.
If port is not specified, it defaults to 6640.
Listens for SSL connections on the specified TCP port. Specify 0 for port to have the kernel automatically choose an available port. If host, which can either be a DNS name (if built with unbound library) or an IP address, is specified, then connections are restricted to the resolved or specified local IP address (either IPv4 or IPv6 address). If host is an IPv6 address, wrap in square brackets, e.g. pssl:6640:[::1]. If host is not specified then it listens only on IPv4 (but not IPv6) addresses. A valid SSL configuration must be provided when this form is used, this can be specified either via command-line options or the SSL table.
If port is not specified, it defaults to 6640.
SSL support is an optional feature that is not always built as part of Open vSwitch.
Listens for connections on the specified TCP port. Specify 0 for port to have the kernel automatically choose an available port. If host, which can either be a DNS name (if built with unbound library) or an IP address, is specified, then connections are restricted to the resolved or specified local IP address (either IPv4 or IPv6 address). If host is an IPv6 address, wrap it in square brackets, e.g. ptcp:6640:[::1]. If host is not specified then it listens only on IPv4 addresses.
If port is not specified, it defaults to 6640.
When multiple clients are configured, the target values must be unique. Duplicate target values yield unspecified results.
true to restrict these connections to read-only transactions, false to allow them to modify the database.
String containing role name for this connection entry.

Client Failure Detection and Handling:
Maximum number of milliseconds to wait between connection attempts. Default is implementation-specific.
Maximum number of milliseconds of idle time on connection to the client before sending an inactivity probe message. If Open vSwitch does not communicate with the client for the specified number of seconds, it will send a probe. If a response is not received for the same additional amount of time, Open vSwitch assumes the connection has been broken and attempts to reconnect. Default is implementation-specific. A value of 0 disables inactivity probes.

Status:

Key-value pair of is_connected is always updated. Other key-value pairs in the status columns may be updated depends on the target type.

When target specifies a connection method that listens for inbound connections (e.g. ptcp: or punix:), both n_connections and is_connected may also be updated while the remaining key-value pairs are omitted.

On the other hand, when target specifies an outbound connection, all key-value pairs may be updated, except the above-mentioned two key-value pairs associated with inbound connection targets. They are omitted.

true if currently connected to this client, false otherwise.
A human-readable description of the last error on the connection to the manager; i.e. strerror(errno). This key will exist only if an error has occurred.
The state of the connection to the manager:
Connection is disabled.
Attempting to reconnect at an increasing period.
Attempting to connect.
Connected, remote host responsive.
Connection is idle. Waiting for response to keep-alive.
These values may change in the future. They are provided only for human consumption.
The amount of time since this client last successfully connected to the database (in seconds). Value is empty if client has never successfully been connected.
The amount of time since this client last disconnected from the database (in seconds). Value is empty if client has never disconnected.
Space-separated list of the names of OVSDB locks that the connection holds. Omitted if the connection does not hold any locks.
Space-separated list of the names of OVSDB locks that the connection is currently waiting to acquire. Omitted if the connection is not waiting for any locks.
Space-separated list of the names of OVSDB locks that the connection has had stolen by another OVSDB client. Omitted if no locks have been stolen from this connection.
When target specifies a connection method that listens for inbound connections (e.g. ptcp: or pssl:) and more than one connection is actually active, the value is the number of active connections. Otherwise, this key-value pair is omitted.
When target is ptcp: or pssl:, this is the TCP port on which the OVSDB server is listening. (This is particularly useful when target specifies a port of 0, allowing the kernel to choose any available port.)

Common Columns:

The overall purpose of these columns is described under Common Columns at the beginning of this document.

SSL configuration for ovn-sb database access.

string
string
string
boolean
string
string

map of string-string pairs

Name of a PEM file containing the private key used as the switch’s identity for SSL connections to the controller.
Name of a PEM file containing a certificate, signed by the certificate authority (CA) used by the controller and manager, that certifies the switch’s private key, identifying a trustworthy switch.
Name of a PEM file containing the CA certificate used to verify that the switch is connected to a trustworthy controller.
If set to true, then Open vSwitch will attempt to obtain the CA certificate from the controller on its first SSL connection and save it to the named PEM file. If it is successful, it will immediately drop the connection and reconnect, and from then on all SSL connections must be authenticated by a certificate signed by the CA certificate thus obtained. This option exposes the SSL connection to a man-in-the-middle attack obtaining the initial CA certificate. It may still be useful for bootstrapping.
List of SSL protocols to be enabled for SSL connections. The default when this option is omitted is TLSv1,TLSv1.1,TLSv1.2.
List of ciphers (in OpenSSL cipher string format) to be supported for SSL connections. The default when this option is omitted is HIGH:!aNULL:!MD5.

Common Columns:

The overall purpose of these columns is described under Common Columns at the beginning of this document.

Each row in this table stores the DNS records. The OVN action dns_lookup uses this table for DNS resolution.

map of string-string pairs
set of 1 or more Datapath_Bindings

map of string-string pairs

Key-value pair of DNS records with DNS query name as the key and a string of IP address(es) separated by comma or space as the value. ovn-northd stores the DNS query name in all lowercase in order to facilitate case-insensitive lookups.
Example: "vm1.ovn.org" = "10.0.0.4 aef0::4"
The DNS records defined in the column records will be applied only to the DNS queries originating from the datapaths defined in this column.

Common Columns:
See External IDs at the beginning of this document.

Role table for role-based access controls.

string
map of string-weak reference to RBAC_Permission pairs

The role name, corresponding to the role column in the Connection table.
A mapping of table names to rows in the RBAC_Permission table.

Permissions table for role-based access controls.

string
set of strings
boolean
set of strings

Name of table to which this row applies.
Set of strings identifying columns and column:key pairs to be compared with client ID. At least one match is required in order to be authorized. A zero-length string is treated as a special value indicating all clients should be considered authorized.
When "true", row insertions and authorized row deletions are permitted.
Set of strings identifying columns and column:key pairs that authorized clients are allowed to modify.

Association of Port_Binding rows of type chassisredirect to a Chassis. The traffic going out through a specific chassisredirect port will be redirected to a chassis, or a set of them in high availability configurations.

string (must be unique within table)
optional weak reference to Chassis
integer, in range 0 to 32,767
map of string-string pairs

map of string-string pairs

Name of the Gateway_Chassis.
A suggested, but not required naming convention is ${port_name}_${chassis_name}.
The Chassis to which we send the traffic.
This is the priority the specific Chassis among all Gateway_Chassis belonging to the same Port_Binding.
Reserved for future use.

Common Columns:

The overall purpose of these columns is described under Common Columns at the beginning of this document.

optional weak reference to Chassis
integer, in range 0 to 32,767

map of string-string pairs

The Chassis which provides the HA functionality.
Priority of the HA chassis. Chassis with highest priority will be the master in the HA chassis group.

Common Columns:
See External IDs at the beginning of this document.

Table representing a group of chassis which can provide High availability services. Each chassis in the group is represented by the table HA_Chassis. The HA chassis with highest priority will be the master of this group. If the master chassis failover is detected, the HA chassis with the next higher priority takes over the responsibility of providing the HA. If ha_chassis_group column of the table Port_Binding references this table, then this HA chassis group provides the gateway functionality and redirects the gateway traffic to the master of this group.

string (must be unique within table)
set of HA_Chassises
set of weak reference to Chassis

map of string-string pairs

Name of the HA_Chassis_Group. Name should be unique.
A list of HA_Chassis which belongs to this group.
The set of Chassis that reference this HA chassis group. To determine the correct Chassis, find the chassisredirect type Port_Binding that references this HA_Chassis_Group. This Port_Binding is derived from some particular logical router. Starting from that LR, find the set of all logical switches and routers connected to it, directly or indirectly, across router ports that link one LRP to another or to a LSP. For each LSP in these logical switches, find the corresponding Port_Binding and add its bound Chassis (if any) to ref_chassis.

Common Columns:
See External IDs at the beginning of this document.

Database table used by ovn-controller to report CMS related events. Please note there is no guarantee a given event is written exactly once in the db. It is CMS responsibility to squash duplicated lines or to filter out duplicated events

string, must be empty_lb_backends
map of string-string pairs
optional weak reference to Chassis
integer

Event type occurred
Key-value pairs used to specify event info to the CMS. Possible values are:
  • vip: VIP reported for the empty_lb_backends event
  • protocol: Transport protocol reported for the empty_lb_backends event
  • load_balancer: UUID of the load balancer reported for the empty_lb_backends event
This column is a Chassis record to identify the chassis that has managed a given event.
Event sequence number. Global counter for controller generated events. It can be used by the CMS to detect possible duplication of the same event.

IP Multicast configuration options. For now only applicable to IGMP.

weak reference to Datapath_Binding (must be unique within table)
optional boolean
optional boolean
optional integer
optional integer
optional integer
integer

string
string
string
optional integer

Datapath_Binding entry for which these configuration options are defined.
Enables/disables multicast snooping. Default: disabled.
Enables/disables multicast querying. If enabled then multicast querying is enabled by default.
Limits the number of multicast groups that can be learned. Default: 2048 groups per datapath.
Configures the idle timeout (in seconds) for IP multicast groups if multicast snooping is enabled. Default: 300 seconds.
Configures the interval (in seconds) for sending multicast queries if snooping and querier are enabled. Default: idle_timeout/2 seconds.
ovn-controller reads this value and flushes all learned multicast groups when it detects that seq_no was changed.

Querier configuration options:

The ovn-controller process that runs on OVN hypervisor nodes uses the following columns to determine field values in IGMP/MLD queries that it originates:

Source Ethernet address.
Source IPv4 address.
Source IPv6 address.
Value (in seconds) to be used as "max-response" field in multicast queries. Default: 1 second.

Contains learned IGMP groups indexed by address/datapath/chassis.

string
optional weak reference to Datapath_Binding
optional weak reference to Chassis
set of weak reference to Port_Bindings

Destination IPv4 address for the IGMP group.
Datapath to which this IGMP group belongs.
Chassis to which this IGMP group belongs.
The destination port bindings for this IGMP group.

Each row in this table configures monitoring a service for its liveness. The service can be an IPv4 TCP or UDP service. ovn-controller periodically sends out service monitor packets and updates the status of the service. Service monitoring for IPv6 services is not supported.

ovn-northd uses this feature to implement the load balancer health check feature offered to the CMS through the northbound database.


string
optional string, either tcp or udp
integer, in range 0 to 65,535
string
string
string
optional string, containing an integer
optional string, containing an integer
optional string, containing an integer
optional string, containing an integer


optional string, one of error, offline, or online


map of string-string pairs

Configuration:

ovn-northd sets these columns and values to configure the service monitor.

IP of the service to be monitored. Only IPv4 is supported.
The protocol of the service.
The TCP or UDP port of the service.
The VIF of the logical port on which the service is running. The ovn-controller that binds this logical_port monitors the service by sending periodic monitor packets.
Source Ethernet address to use in the service monitor packet.
Source IPv4 address to use in the service monitor packet.
The interval, in seconds, between service monitor checks.
The time, in seconds, after which the service monitor check times out.
The number of successful checks after which the service is considered online.
The number of failure checks after which the service is considered offline.

Status Reporting:

The ovn-controller on the chassis that hosts the logical_port updates this column to report the service’s status.

For TCP service, ovn-controller sends a SYN to the service and expects an ACK response to consider the service to be online.
For UDP service, ovn-controller sends a UDP packet to the service and doesn’t expect any reply. If it receives an ICMP reply, then it considers the service to be offline.

Common Columns:
See External IDs at the beginning of this document.

Each row represents a load balancer.

string
map of string-string pairs
optional string, one of sctp, tcp, or udp
set of Datapath_Bindings
optional Logical_DP_Group

optional string
optional string, either true or false


map of string-string pairs

A name for the load balancer. This name has no special meaning or purpose other than to provide convenience for human interaction with the ovn-nb database.
A map of virtual IP addresses (and an optional port number with : as a separator) associated with this load balancer and their corresponding endpoint IP addresses (and optional port numbers with : as separators) separated by commas.
Valid protocols are tcp, udp, or sctp. This column is useful when a port number is provided as part of the vips column. If this column is empty and a port number is provided as part of vips column, OVN assumes the protocol to be tcp.
Datapaths to which this load balancer applies to.
The group of datapaths to which this load balancer applies to. This means that the same load balancer applies to all datapaths in a group.

Load_Balancer options:
IP to be used as source IP for packets that have been hair-pinned after load balancing. This value is automatically populated by ovn-northd.
This value is automatically set to true by ovn-northd when original destination IP and transport port of the load balanced packets are stored in registers reg1, reg2, xxreg1.

Common Columns:
See External IDs at the beginning of this document.

Contains BFD parameter for ovn-controller bfd configuration.


integer, in range 49,152 to 65,535
integer
string
string
integer
integer
integer
map of string-string pairs
map of string-string pairs


string, one of admin_down, down, init, or up

Configuration:
udp source port used in bfd control packets. The source port MUST be in the range 49152 through 65535 (RFC5881 section 4).
A unique, nonzero discriminator value generated by the transmitting system, used to demultiplex multiple BFD sessions between the same pair of systems.
OVN logical port when BFD engine is running.
BFD peer IP address.
This is the minimum interval, in milliseconds, that the local system would like to use when transmitting BFD Control packets, less any jitter applied. The value zero is reserved.
This is the minimum interval, in milliseconds, between received BFD Control packets that this system is capable of supporting, less any jitter applied by the sender. If this value is zero, the transmitting system does not want the remote system to send any periodic BFD Control packets.
Detection time multiplier. The negotiated transmit interval, multiplied by this value, provides the Detection Time for the receiving system in Asynchronous mode.
Reserved for future use.
See External IDs at the beginning of this document.

Status Reporting:
BFD port logical states. Possible values are:
  • admin_down
  • down
  • init
  • up

This table is primarily used to learn the MACs observed on a VIF (or a localnet port with ’localnet_learn_fdb’ enabled) which belongs to a Logical_Switch_Port record in OVN_Northbound whose port security is disabled and ’unknown’ address set. If port security is disabled on a Logical_Switch_Port record, OVN should allow traffic with any source mac from the VIF. This table will be used to deliver a packet to the VIF, If a packet’s eth.dst is learnt.

string
integer, in range 1 to 16,777,215
integer, in range 1 to 16,777,215

The learnt mac address.
The key of the datapath on which this FDB was learnt.
The key of the port binding on which this FDB was learnt.

Each record represents a Static_MAC_Binding entry for a logical router.

string
string
string
boolean
Datapath_Binding

The logical router port for the binding.
The bound IP address.
The Ethernet address to which the IP is bound.
Override dynamically learnt MACs.
The logical datapath to which the logical router port belongs.

Each record represents the set of template variable instantiations for a given chassis and is populated by ovn-northd from the contents of the OVN_Northbound.Chassis_Template_Var table.

string (must be unique within table)
map of string-string pairs

The chassis this set of variable values applies to.
The set of variable values for a given chassis.
DB Schema 20.27.0 Open vSwitch 23.03.0