iSCSI Initiator for LinuxΒΆ
Prerequisite:
Package
iscsi-initiator-utils
Package
device-mapper-multipath
Installing:
Install the iSCSI initiator and multipath tools:
yum install iscsi-initiator-utils
yum install device-mapper-multipath
Configuring:
Create the default
/etc/multipath.conf
file and enable themultipathd
service:mpathconf --enable --with_multipathd y
Add the following to the
/etc/multipath.conf
file:devices { device { vendor "LIO-ORG" hardware_handler "1 alua" path_grouping_policy "failover" path_selector "queue-length 0" failback 60 path_checker tur prio alua prio_args exclusive_pref_bit fast_io_fail_tmo 25 no_path_retry queue } }
Restart the
multipathd
service:systemctl reload multipathd
iSCSI Discovery and Setup:
Enable CHAP authentication and provide the initiator CHAP username and password by uncommenting and setting the following options in the
/etc/iscsi/iscsid.conf
file:node.session.auth.authmethod = CHAP node.session.auth.username = myusername node.session.auth.password = mypassword
If you intend to use mutual (bidirectional) authentication, provide the target CHAP username and password:
node.session.auth.username_in = mytgtusername node.session.auth.password_in = mytgtpassword
Discover the target portals:
iscsiadm -m discovery -t st -p 192.168.56.101
192.168.56.101:3260,1 iqn.2003-01.org.linux-iscsi.rheln1 192.168.56.102:3260,2 iqn.2003-01.org.linux-iscsi.rheln1
Log in to the target:
iscsiadm -m node -T iqn.2003-01.org.linux-iscsi.rheln1 -l
Multipath IO Setup:
The multipath daemon (
multipathd
) uses themultipath.conf
settings to set up devices automatically. Running themultipath
command shows that the devices have been set up in a failover configuration. Notice that each path has been placed into its own priority group:multipath -ll
mpathbt (360014059ca317516a69465c883a29603) dm-1 LIO-ORG ,IBLOCK size=1.0G features='0' hwhandler='1 alua' wp=rw |-+- policy='queue-length 0' prio=50 status=active | `- 28:0:0:1 sde 8:64 active ready running `-+- policy='queue-length 0' prio=10 status=enabled `- 29:0:0:1 sdc 8:32 active ready running
You should now be able to use the RBD image in the same way that you would use a normal multipath iSCSI disk.
Log out of the target:
iscsiadm -m node -T iqn.2003-01.org.linux-iscsi.rheln1 -u