4.8.3 Creating iSCSI Target

Set the following configuration for all nodes in which the mirroring function among servers is used.

The "current node" in the following procedure indicates: node 1 if you execute the procedure on the node 1; node 2 if you execute the procedure on the node 2.

Execute targetcli to be an interactive mode.
# targetcli
Set not to add a default portal automatically.
/> set global auto_add_default_portal=false
Register a disk or a partition of a local node for the mirroring among servers.
/> /backstores/block/ create storage_name device_path
Point
- Specify arbitrary characters (255 characters or less) to storage_name.
- For device_path, specify the path for the by-id file of a disk or a partition on a local node which is used for the mirroring among servers.
  In an Azure environment, a NIFCLOUD environment, or an environment where the by-id file does not exist, do not specify the path for the by-id file, but create a partition in the disk where the gpt disk label is set, and specify the path for the by-partuuid file for that partition.
- If there are plural disks for the mirroring among servers on a local node, perform the procedure for each disk.
Execution example
/> /backstores/block/ create storage1 /dev/disk/by-id/scsi-3500000e111c56611
Check the setting of device.
Execute the following command to check that emulate_write_cache is 0.
/> /backstores/block/storage_name get attribute emulate_write_cache
Point
Specify the storage name set in the step 3 to storage_name.
Execution example
/> /backstores/block/storage1 get attribute emulate_write_cache emulate_write_cache=0
Create iSCSI target.
/> /iscsi/ create

Check the created iSCSI target.

/> /iscsi/ ls

Execution example

/> /iscsi/ ls
o- iscsi ..................................................................... [Targets: 1]
  o- iqn.2003-01.org.linux-iscsi.node1.x8664:sn.2613f8620d98 .................... [TPGs: 1]
    o- tpg1 ........................................................ [no-gen-acls, no-auth]
      o- acls ................................................................... [ACLs: 0]
      o- luns ................................................................... [LUNs: 0]
      o- portals ............................................................. [Portals: 0]

This example shows that iqn name "iqn.2003-01.org.linux-iscsi.node1.x8664:sn.2613f8620d98" was created and the target was created in /iscsi/.

/> /iscsi/iqn_name/tpgX/acls create initiator_name_of_node1
/> /iscsi/iqn_name/tpgX/acls create initiator_name_of_node2

Point

Specify the iqn name confirmed in the step 6 to iqn_name.
Specify the directory name (Example: tpg1) created in the iqn_name directory to tpgX.
Initiator name can be confirmed in the /etc/iscsi/initiatorname.iscsi file.

Execution example

/> /iscsi/iqn.2003-01.org.linux-iscsi.node1.x8664:sn.2613f8620d98/tpg1/acls create \
iqn.1994-05.com.redhat:dee92ff9979d
/> /iscsi/iqn.2003-01.org.linux-iscsi.node1.x8664:sn.2613f8620d98/tpg1/acls create  \
iqn.1994-05.com.redhat:fa7eb9cf483c

Note

An iSCSI initiator name needs to be differed in each node of the cluster system.

If an iSCSI initiator name in each node is identical, change it to a different iSCSI initiator name in each node.

See the following procedure to change an iSCSI initiator name.

Determine a new iSCSI initiator name.
Use the following command to create an initiator name with random ID.
(Example)
```
# iscsi-iname
iqn.1994-05.com.redhat:5ea612eab618
```
Change a configuration file.
In the /etc/iscsi/initiatorname.iscsi file, rewrite a character string following "InitiatorName=" to the iSCSI initiator name of the step 1.
(Example)
[Before change]
```
InitiatorName=iqn.1994-05.com.redhat:4539cd846026
```
[After change]
```
InitiatorName=iqn.1994-05.com.redhat:5ea612eab618
```
Restart iscsid to update the configuration.
(Example)
```
# systemctl restart iscsid.service
```

Connect the device registered in the step 3.
/> /iscsi/iqn_name/tpgX/luns create /backstores/block/storage_name
Point
- Specify iqn name confirmed in the step 6 to iqn_name.
- Specify the directory name (Example: tpg1) created in the iqn_name directory to tpgX.
- Specify the storage name set in the step 3 to storage_name.
- If there are plural disks for the mirroring among servers on a local node, perform the procedure for each disk.
Execution example
/> /iscsi/iqn.2003-01.org.linux-iscsi.node1.x8664:sn.2613f8620d98/tpg1/luns create \ /backstores/block/storage1
Register IP address for the target.
/> /iscsi/iqn_name/tpgX/portals create IPaddress
Point
- Specify the iqn name confirmed in the step 6 to iqn_name.
- Specify the directory name (Example: tpg1) created in the iqn_name directory to tpgX.
- Specify IP address for the mirroring among servers on a local node to IPaddress.
  IPv4 address or IPv6 address can be set.
  IP address of cip can not be specified. Use IP address assigned NIC (such as eth0) directly.
  For conditions for NIC and IP address, refer to "3.9.1 Network Configuration."
Execution example
/> /iscsi/iqn.2003-01.org.linux-iscsi.node1.x8664:sn.2613f8620d98/tpg1/portals create \ 192.168.125.123
End the interactive mode of targetcli. This operation records the settings.
/> exit

Confirm the target configuration.

# targetcli ls

Point

(*1) Confirm that the path for the by-id file of the device used for the mirroring among servers was output.
If the by-partuuid file is specified in an Azure environment, a NIFCLOUD environment, or an environment where the by-id file does not exist, confirm that the path for the by-partuuid file is output.

(*2) Confirm that iSCSI initiator name for each cluster node was output.

(*3) Confirm that the storage confirmed in (*1) was assigned for each iSCSI initiator.

(*4) Confirm that IP address of a local node for the mirroring among servers was output.

Execution example

# targetcli ls
o- / .............................................................................. [...]
  o- backstores ................................................................... [...]
  | o- block ....................................................... [Storage Objects: 1]
  | | o- storage1 . [/dev/disk/by-id/scsi-3500000e111c56611 (8.0GiB) write-thru activated] (*1)
  | o- fileio ...................................................... [Storage Objects: 0]
  | o- pscsi ....................................................... [Storage Objects: 0]
  | o- ramdisk ..................................................... [Storage Objects: 0]
  o- iscsi ................................................................. [Targets: 1]
  | o- iqn.2003-01.org.linux-iscsi.node1.x8664:sn.2613f8620d98 ................ [TPGs: 1]
  |   o- tpg1 .................................................... [no-gen-acls, no-auth]
  |     o- acls ............................................................... [ACLs: 2]
  |     | o- iqn.1994-05.com.redhat:dee92ff9979d ........................ [Mapped LUNs: 1] (*2)
  |     | | o- mapped_lun0 .................................... [lun0 block/storage1 (rw)] (*3)
  |     | o- iqn.1994-05.com.redhat:fa7eb9cf483c ........................ [Mapped LUNs: 1] (*2)
  |     |   o- mapped_lun0 .................................... [lun0 block/storage1 (rw)] (*3)
  |     o- luns ............................................................... [LUNs: 1]
  |     | o- lun0 ............. [block/storage1 (/dev/disk/by-id/scsi-3500000e111c56611)]
  |     o- portals ......................................................... [Portals: 1]
  |       o- 192.168.125.123:3260 ................................................... [OK] (*4)
  o- loopback .............................................................. [Targets: 0]