DOKK / manpages / debian 10 / logcentral-tools / logForwarder.1.en
LOGFORWARDER(1) LOGFORWARDER(1)

logForwarder - Log item to manage ssh tunnels between log components and tools

logForwarder - Tools for creating and maintaining ssh tunnels between log components in complex topologies

logForwarder [options] ...


logForwarder helps simplifying the maintenance of ssh tunnels between log components and tools, thus improving log scalability and configuration in complex network topologies. The components may be defined in a program to be monitored, they publish messages in the LogCentral. The tools get the messages subscribing to the LogCentral.

Before starting a log forwarder, you must:

  • launch omniNames on the local and remotes hosts.
  • launch the remote peer only defining its name and network configuration.
  • launch local peer and give him remote peer's name, ssh connection informations, remote port to use and pass -C option to create the ssh tunnel.

[Remark: forwarders must be launched before the log tools/components]

String identifying the forwarder
String identifying its peer on the other network
Host hosting the ssh tunnel
Login used to establish the ssh connection (default: current user login).
Path to the ssh key (the private one !) used to establish the ssh connection (default: $HOME/.ssh/id_rsa).
Port listening on the ssh host.
Host to which the connection is made by the tunnel (corresponds to ssh options -L and -R).
Number of times that the local forwarder will try to bind itself to the remote forwarder (default: 3).
Pass remote forwarder's IOR. By default, the local forwarder will retrive its peer IOR.
Path to configuration file.
Create the tunnel from this forwarder.

You can pass a configuration file to dietForwarder instead of using command line options through the --net-config option. Configuration file lists several rules describing networks reachable using this forwarder.

There's two category of rules:

describe which networks are accessible through the forwarder.
describe which networks are not accessible through the forwarder.

A rule always starts by either accept: or reject: immediately followed by a regular expression (Posix) describing host concerned by the rule. Rules are evaluated in the following order: accept then reject. For instance:

accept:.* reject:localhost


This fragment means that the forwarder will accept connections to every hosts but localhost.

Here's a simple configuration:

  • We have two domains: net1 and net2, forwarders will be launched on hosts fwd.net1 and fwd.net2.
  • There's no link between hosts fwd.net1 and fwd.net2 but user may access fwd.net2 from fwd.net1 using a ssh connection.
  • We'll name fwd.net1 forwarder Fwd1 and fwd.net2 fowarder Fwd2.
  • One tool lives in fwd.net2 while a component lives on the net1 domain.

Command line for launchind Fwd1

fwd.net1$ logForwarder --name Fwd1 --peer-name Fwd2 \


  --ssh-host fwd.net2 --ssh-login dietUser \


  --ssh-key id rsa net2 --remote-port 50000 \


  --net-config net1.cfg -C


Command line to launch Fwd2

fwd.net2$ logForwarder --name Fwd2 --net-config net2.cfg


Configuration file for Fwd1

In this example, the forwarders Fwd1 accepts only the connections to fwd.net2.

accept:fwd.net2


Configuration file for Fwd2

In this example, the forwarders Fwd2 accepts all the connections except those which are for the localhost.

accept:.*
reject:localhost


The log service uses CORBA as its communication layer. While it's a flexible and robust middleware, it remains hard deploying the log on heterogeneous networks that are not reachable except through ssh tunnels. Log forwarders help administrator configuring their grid without manually set-up ssh tunnels which arguably is neither simple nor scalable. Log forwarders make it very easy configuring such topologies.

(C)2011, GRAAL, INRIA Rhone-Alpes, 46 allee d'Italie, 69364 Lyon cedex 07, France all right reserved <diet-dev@ens-lyon.fr>

This program is free software: you can redistribute it and/or mod‐ ify it under the terms of the GNU General Public License as pub‐ lished by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Pub- lic Li‐ cense for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>.

GRAAL INRIA Rhone-Alpes 46 allee d'Italie 69364 Lyon cedex 07, FRANCE Email: <diet-dev@ens-lyon.fr> WWW: http://graal.ens-lyon.fr/DIET

omniNames(1), dietForwarder(1), LogCentral(1)

On some systems, forwarder rules won't work unless you use IP addresses instead of hostnames

haikel.guemar@sysfera.com, kevin.coulomb@sysfera.com

License: GPLv3

DIET developers

2011-05-11 0.1