Simple iSCSI target and initiator setup

Simple iSCSI target and initiator

Setup iSCSI target:

We will use FreeBSD and its CAM Target Layer (CTL) as an iSCSI target.

The example FreeBSD installation will have the IP address 192.168.1.32

Verify that you see all the block devices intended for iSCSI LUNs to be created. You can make use of zvol-backed LUNs, generic block device-backed LUNs or file-backed LUNs.

If you intend to use zvol-backed LUNs, then:

Create zpool where the zvols for LUNs will reside:

# zpool create -m none -O volmode=dev zpool_iscsi /dev/vtbd1

Create zvol(s) for the LUNs:

# zfs create -o volmode=dev -V 9g zpool_iscsi/pg0-vol0

Create /etc/ctl.conf:

portal-group pg0 {
    discovery-auth-group no-authentication
    listen 0.0.0.0
    listen [::]
}

target iqn.2017-01.org.danubecloud:target0 {
    auth-group no-authentication
    portal-group pg0

    lun 0 {
            backend block
            path /dev/zvol/zpool_iscsi/pg0-vol0
            blocksize 4096
            device-id FREEBSD
            serial 00010001
    }
}

pg0 is an arbitrary name chosen for, so called, portal group.

Set mode 0600 on /etc/ctl.conf

chmod 600 /etc/ctl.conf

Enable ctld in /etc/rc.conf and start ctld:

# echo 'ctld_enable="YES"' >> /etc/rc.conf
# service ctld start

Verify that you see the LUNs:

# ctladm devlist
LUN Backend       Size (Blocks)   BS Serial Number    Device ID
  0 block               2359296 4096 00010001         FREEBSD

Initiator

Install Danube Cloud node

Enable iSCSI initiator in global zone:

# svcadm enable -r svc:/network/iscsi/initiator:default

Setup iSCSI discovery address:

# iscsiadm add discovery-address **192.168.1.32**

The IP address 192.168.1.32 is the address that the iSCSI target has. If you plan to use multihoming, just specify the respective IP address where the iSCSI should communicate.

Enable iSCSI sendtargets discovery method:

# iscsiadm modify discovery -t enable

5. verify that you see iscsi targets:

In dmesg:

/scsi_vhci/disk@g465245454253442046524545425344000000000000000000 (sd2) online

In iostat -En:

# iostat -En
c1t465245454253442046524545425344000000000000000000d0 Soft Errors: 0 Hard Errors: 0 Transport Errors: 0
Vendor: FREEBSD  Product: CTLDISK          Revision: 0001 Serial No: 00010001
Size: 9.66GB <9663676416 bytes>
Media Error: 0 Device Not Ready: 0 No Device: 0 Recoverable: 0
Illegal Request: 0 Predictive Failure Analysis: 0

Create zpool on iSCSI:

# zpool create iscsi /dev/dsk/c1t465245454253442046524545425344000000000000000000d0

You are all set!

And be careful to not create situation where global zone would depend on iSCSI target that has not been booted yet!