Shared Resource creation using ISCSI package through LINUX

ISCSI shared storage creation:

ISCSI target:

sudo apt-get install iscsitarget

Open /etc/default/iscsitarget.

vi /etc/default/iscsitarget

... and set ISCSITARGET_ENABLE to true:

ISCSITARGET_ENABLE=true 

 We can use unused logical volumes, image files, 

hard drives (e.g. /dev/sdb), hard drive partitions 

(e.g. /dev/sdb1) or RAID devices (e.g. /dev/md0) for the storage. 

In this example, I will create a logical volume of 20GB named 

storage_lun1 in the volume group vg0:

lvcreate -L15G -n storage_lun1 vg0

(If you want to use an image file, you can create it as follows:

mkdir /storage

dd if=/dev/zero of=/storage/lun1.img bs=1024k count=20000

This creates the image file /storage/lun1.img with a size of 20GB.

)

Next we edit /etc/ietd.conf...

vi /etc/ietd.conf

... and comment out everything in that file. At the end we add the following stanza:

[...]
Target iqn.2014-05.com.example:storage.lun1
        IncomingUser someuser secret
        OutgoingUser
        Lun 0 Path=/dev/vg0/storage_lun1,Type=fileio
        Alias LUN1
        #MaxConnections  6

Now we tell the target that we want to allow connections to the device iqn.2014-05.com.example:storage.lun1 from the IP address 172.31.132.55 (server1.example.com) and 172.31.132.59 (server2.example.com)...

vi /etc/initiators.allow

[...]
iqn.2014-05.com.example:storage.lun1 172.31.132.55, 172.31.132.59
and start the target:

/etc/init.d/iscsitarget start

2.2. ISCSI initiator

sudo apt-get install open-iscsi

Next we open /etc/iscsi/iscsid.conf...

vi /etc/iscsi/iscsid.conf

... and set node.startup to automatic:

[...]
node.startup = automatic
[...]
Then we restart the initiator:

/etc/init.d/open-iscsi restart

Now we connect to the target (iscsi.example.com) and check what storage devices it has to offer:

iscsiadm -m discovery -t st -p 172.31.132.60 (shared resource IP address)

server1:~# iscsiadm -m discovery -t st -p 172.31.132.60
172.31.132.60:3260,1 iqn.2014-05.com.example:storage.lun1

The settings for the storage device iqn.2014-05.com.example:storage.lun1 on 192.168.0.102:3260,1 are stored in the file /etc/iscsi/nodes/iqn.2001-04.com.example:storage.lun1/172.31.132.60 ,3260,1/default. We need to set the username and password for the target in that file; instead of editing that file manually, we can use the iscsiadm command to do this for us:

iscsiadm -m node --targetname "iqn.2014-05com.example:storage.lun1" --portal "172.31.132.60 :3260" --op=update --name node.session.auth.authmethod --value=CHAP
iscsiadm -m node --targetname "iqn.2014-05.com.example:storage.lun1" --portal "172.31.132.60 :3260" --op=update --name node.session.auth.username --value=someuser
iscsiadm -m node --targetname "iqn.2014-05.com.example:storage.lun1" --portal "1172.31.132.60 :3260" --op=update --name node.session.auth.password --value=secret

Now we can log in by running...

sudo iscsiadm -m node --targetname "iqn.2014-05.com.example:storage.lun1" --portal "1172.31.132.60 :3260" --login