Configuration iSCSI Server and Initiator in RHEL 7 / RHEL 8

Configure the iSCSI Server 

1. Install the targetcli in iSCSI Server

[root@iscsiserver ~]# yum install targetcli

2. Enable and start the target service

        

[root@iscsiserver ~]# systemctl enable target; systemctl start target

3. Open SCSI server port on the firewall as permanent change and reload the configuration for immediate user

[root@iscsiserver ~]# firewall-cmd --permanent --add-port=3260/tcp
[root@iscsiserver ~]# firewall-cmd --reload

4. We have a disk /dev/sdb (2GB)  and we are going add that as a  Backstores block device using targetcli tool.

[root@iscsiserver ~]# targetcli
targetcli shell version 2.1.53
Copyright 2011-2013 by Datera, Inc and others.
For help on commands, type 'help'.

/> cd backstores/
/backstores> block/ create blocklun1 /dev/sdb
Created block storage object blocklun1 using /dev/sdb.
/backstores> ls
o- backstores .................................................................................................. [...]
  o- block ...................................................................................... [Storage Objects: 1]
  | o- blocklun1 .......................................................... [/dev/sdb (2.0GiB) write-thru deactivated]
  |   o- alua ....................................................................................... [ALUA Groups: 1]
  |     o- default_tg_pt_gp ........................................................... [ALUA state: Active/optimized]
  o- fileio ..................................................................................... [Storage Objects: 0]
  o- pscsi ...................................................................................... [Storage Objects: 0]
  o- ramdisk .................................................................................... [Storage Objects: 0]
/backstores>

 5. Create a unique iSCSI qualified Name (IQN) for the target . IQN will be iqn.2021-12.com.example:iscsiserver

[root@iscsiserver ~]# targetcli
targetcli shell version 2.1.53
Copyright 2011-2013 by Datera, Inc and others.
For help on commands, type 'help'.

/> iscsi/ create  iqn.2021-12.com.example:iscsiserver
Created target iqn.2021-12.com.example:iscsiserver.
Created TPG 1.
Global pref auto_add_default_portal=true
Created default portal listening on all IPs (0.0.0.0), port 3260.
/> ls iscsi/
o- iscsi ................................................................................................ [Targets: 1]
  o- iqn.2021-12.com.example:iscsiserver ................................................................... [TPGs: 1]
    o- tpg1 ................................................................................... [no-gen-acls, no-auth]
      o- acls .............................................................................................. [ACLs: 0]
      o- luns .............................................................................................. [LUNs: 0]
      o- portals ........................................................................................ [Portals: 1]
        o- 0.0.0.0:3260 ......................................................................................... [OK]

6. Create an ACL for the iscsiclient (initiator). The initiator will be connecting with the name iqn.2021-12.com.example:iscsiclient.

[root@iscsiserver ~]# targetcli
targetcli shell version 2.1.53
Copyright 2011-2013 by Datera, Inc and others.
For help on commands, type 'help'.

/> iscsi/iqn.2021-12.com.example:iscsiserver/tpg1/acls create  iqn.2021-12.com.example:iscsiclient
Created Node ACL for iqn.2021-12.com.example:iscsiclient
/> ls iscsi/
o- iscsi ........................................................................................ [Targets: 1]
  o- iqn.2021-12.com.example:iscsiserver ........................................................... [TPGs: 1]
    o- tpg1 ........................................................................... [no-gen-acls, no-auth]
      o- acls ...................................................................................... [ACLs: 1]
      | o- iqn.2021-12.com.example:iscsiclient .............................................. [Mapped LUNs: 0]
      o- luns ...................................................................................... [LUNs: 0]
      o- portals ................................................................................ [Portals: 1]
        o- 0.0.0.0:3260 ................................................................................. [OK]

7. Create the LUN under the target, the LUN should use the previously defined backing storage device name blocklun1.

[root@iscsiserver ~]# targetcli
targetcli shell version 2.1.53
Copyright 2011-2013 by Datera, Inc and others.
For help on commands, type 'help'.

/> /iscsi/iqn.2021-12.com.example:iscsiserver/tpg1/luns create /backstores/block/blocklun1
Created LUN 0.
Created LUN 0->0 mapping in node ACL iqn.2021-12.com.example:iscsiclient
/> ls /iscsi/
o- iscsi ...................................................................................... [Targets: 1]
  o- iqn.2021-12.com.example:iscsiserver ......................................................... [TPGs: 1]
    o- tpg1 ......................................................................... [no-gen-acls, no-auth]
      o- acls .................................................................................... [ACLs: 1]
      | o- iqn.2021-12.com.example:iscsiclient ............................................ [Mapped LUNs: 1]
      |   o- mapped_lun0 ....................................................... [lun0 block/blocklun1 (rw)]
      o- luns .................................................................................... [LUNs: 1]
      | o- lun0 ..............................................block/blocklun1 (/dev/sdb) (default_tg_pt_gp)]
      o- portals .............................................................................. [Portals: 1]
        o- 0.0.0.0:3260 ............................................................................... [OK]

8. Delete port 0.0.0.0:3260 and Configure the portal for the target to listen on specific IP Address 192.168.31.252.

[root@iscsiserver ~]# targetcli
targetcli shell version 2.1.53
Copyright 2011-2013 by Datera, Inc and others.
For help on commands, type 'help'.

/> /iscsi/iqn.2021-12.com.example:iscsiserver/tpg1/portals delete 0.0.0.0 3260
Deleted network portal 0.0.0.0:3260
/> /iscsi/iqn.2021-12.com.example:iscsiserver/tpg1/portals create 192.168.31.252 3260
Using default IP port 3260
Created network portal 192.168.31.252:3260.
/> ls iscsi/
o- iscsi ....................................................................................... [Targets: 1]
  o- iqn.2021-12.com.example:iscsiserver .......................................................... [TPGs: 1]
    o- tpg1 .......................................................................... [no-gen-acls, no-auth]
      o- acls ..................................................................................... [ACLs: 1]
      | o- iqn.2021-12.com.example:iscsiclient ............................................. [Mapped LUNs: 1]
      |   o- mapped_lun0 ........................................................ [lun0 block/blocklun1 (rw)]
      o- luns ..................................................................................... [LUNs: 1]
      | o- lun0 ............................................. [block/blocklun1 (/dev/sdb) (default_tg_pt_gp)]
      o- portals ............................................................................... [Portals: 1]
        o- 192.168.31.252:3260 ......................................................................... [OK]

 9. View the full configruation.

[root@iscsiserver ~]# targetcli
targetcli shell version 2.1.53
Copyright 2011-2013 by Datera, Inc and others.
For help on commands, type 'help'.

/> ls
o- / ............................................................................................. [...]
  o- backstores .................................................................................. [...]
  | o- block ...................................................................... [Storage Objects: 1]
  | | o- blocklun1 ............................................ [/dev/sdb (2.0GiB) write-thru activated]
  | |   o- alua ....................................................................... [ALUA Groups: 1]
  | |     o- default_tg_pt_gp ........................................... [ALUA state: Active/optimized]
  | o- fileio ..................................................................... [Storage Objects: 0]
  | o- pscsi ...................................................................... [Storage Objects: 0]
  | o- ramdisk .................................................................... [Storage Objects: 0]
  o- iscsi ................................................................................ [Targets: 1]
  | o- iqn.2021-12.com.example:iscsiserver ................................................... [TPGs: 1]
  |   o- tpg1 ................................................................... [no-gen-acls, no-auth]
  |     o- acls .............................................................................. [ACLs: 1]
  |     | o- iqn.2021-12.com.example:iscsiclient ...................................... [Mapped LUNs: 1]
  |     |   o- mapped_lun0 ................................................. [lun0 block/blocklun1 (rw)]
  |     o- luns .............................................................................. [LUNs: 1]
  |     | o- lun0 ...................................... [block/blocklun1 (/dev/sdb) (default_tg_pt_gp)]
  |     o- portals ........................................................................ [Portals: 1]
  |       o- 192.168.31.252:3260 .................................................................. [OK]
  o- loopback ............................................................................. [Targets: 0] 

 10. Exit and save the configuration to the default file /etc/target/saveconfig.json

/> exit
Global pref auto_save_on_exit=true
Last 10 configs saved in /etc/target/backup/.
Configuration saved to /etc/target/saveconfig.json