Installing iSCSI Target
Open terminal and use
yum command to search for the package name which need to get install for iscsi
target.
# yum search iscsi
Sample Output
========================== N/S matched: iscsi
=======================
iscsi-initiator-utils.x86_64 : iSCSI daemon
and utility programs
iscsi-initiator-utils-devel.x86_64 :
Development files for iscsi-initiator-utils
lsscsi.x86_64 : List SCSI devices (or hosts)
and associated information
scsi-target-utils.x86_64 : The SCSI target
daemon and utility programs
We got the search result
as above, choose the Target package
and install to play around.
# yum install scsi-target-utils -y
List the installed package to know the default config, service,
and man page location.
# rpm -ql scsi-target-utils.x86_64
Let’s start the iSCSI
Service, and check the status of Service up and running, iSCSI service named
as tgtd.
# /etc/init.d/tgtd start
# /etc/init.d/tgtd status
Now we need to configure it to start Automatically while system
start-up.
# chkconfig tgtd on
Next, verify that the
run level configured correctly for the tgtd service.
# chkconfig --list tgtd
Let’s use tgtadm to list what targets and LUNS we currently got
configured in our Server.
# tgtadm --mode target --op show
The tgtd installed up and running, but there is no Output from the above command because we have not yet
defined the LUNs in Target Server. For manual page, Run ‘man‘ command.
Finally we need to add
iptables rules for iSCSI if there is iptables deployed in your target Server.
First, find the Port number of iscsi target using following netstat command,
The target always listens on TCP port 3260.
# netstat -tulnp | grep tgtd
Next add the following rules to allow iptables to Broadcast the
iSCSI target discovery.
# iptables -A INPUT -i eth0 -p tcp --dport 860
-m state --state NEW,ESTABLISHED -j ACCEPT
# iptables -A INPUT -i eth0 -p tcp --dport
3260 -m state --state NEW,ESTABLISHED -j ACCEPT
Note: Rule may vary according to your Default CHAIN Policy. Then save the Iptables and restart the
iptables.
# iptables-save
# /etc/init.d/iptables restart
Creating LUNs using LVM in iSCSI Target Server
First of all list the blocks by lsblk command.
Now let’s Partition
the drive using fdisk command as shown below.
# fdisk
/dev/sda
Choose n to create a New Partition.
.
Command (m for help): n
Choose p to create a Primary partition
Command action
e
extended
p
primary partition (1-4)
Give a Partition
number which we need to create.
Partition number (1-4): 1
As here, we are going
to setup a LVM drive. So, we need to use the default settings to use full size
of Drive.
First sector (2048-37748735, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G}
(2048-37748735, default 37748735):
Using default value 37748735
Choose the type of partition, Here we need to setup a LVM so
use 8e. Use l option to see
the list of type.
Command (m for help): t
Choose which partition
want to change the type.
Selected partition 1
Hex code (type L to list codes): 8e
Changed system type of partition 1 to 8e
(Linux LVM)
After changing the type, check the changes by print (p) option to list the partition table.
Command (m for help): p
Disk /dev/sda: 19.3 GB, 19327352832 bytes
255 heads, 63 sectors/track, 2349 cylinders,
total 37748736 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes /
512 bytes
I/O size (minimum/optimal): 512 bytes / 512
bytes
Disk identifier: 0x9fae99c8
Device Boot Start End Blocks
Id System
/dev/sda1 2048 37748735
18873344 8e Linux LVM
Write the changes using w to exit from
fdisk utility, Restart the system to make changes.
Creating Logical Volumes for LUNs
Now here, we going to
create Physical volume using using ‘pvcreate’ command.
# pvcreate /dev/sda1
Create a Volume group
with name of iSCSI to identify the group.
# vgcreate vg_iscsi /dev/sda1
Here I’m defining 4
Logical Volumes, if so there will be 4 LUNs in our iSCSI Target server.
# lvcreate -L 4G -n lv_iscsi vg_iscsi
# lvcreate -L 4G -n lv_iscsi-1 vg_iscsi
# lvcreate -L 4G -n lv_iscsi-2 vg_iscsi
# lvcreate -L 4G -n lv_iscsi-3 vg_iscsi
List the Physical
volume, Volume group, logical volumes to confirm.
# pvs
&& vgs && lvs
# lvs
Define LUNs in Target Server
We have created
Logical Volumes and ready to use with LUN, here we to define the LUNs in target
configuration, if so only it will be available for client machines
(Initiators).
Open and edit Targer
configuration file located at ‘/etc/tgt/targets.conf’ with your choice of
editor.
# vim
/etc/tgt/targets.conf
Append the following
volume definition in target conf file. Save and close the file.
1.
ISCSI qualified name
(iqn.2014-07.com.tecmint:tgt1).
2.
Use whatever as your wish.
3.
Identify using target, 1st target in this
Server.
4.
LVM Shared for
particular LUN.
<target
iqn.2017-07.com.openpath:tgt1>
backing-store
/dev/vg_iscsi/lv_iscsi
</target>
Next, reload the configuration by starting tgd service as shown below.
#
/etc/init.d/tgtd reload
Next verify the
available LUNs using the following command.
# tgtadm
--mode target --op show
Initiator Client
Setup
1. In Client side, we need to install the package
‘iSCSI-initiator-utils
# yum
install iscsi-initiator-utils.x86_64
3. After installing the
package, we need to discover the share from Target server.
The client side commands little hard to remember, so we can use man page to get
the list of commands which required to run.
# man
iscsiadm
4. Press SHIFT+G to Navigate to the Bottom of the man page and scroll
little up to get the login example commands. We need to replace our Target servers IP address in below command Discover the
Target.
# iscsiadm
--mode discoverydb --type sendtargets --portal 192.168.0.200 --discover
192.168.0.200:3260,1
iqn.2017-07.com.openpath:tgt1
192.168.0.200 will be the server i.e target iscsi
ip.
5. Here we got the iSCSI
(iqn) qualified name from above command execution.
192.168.0.200:3260,1
iqn.2017-07.com.openpath:tgt1
# /etc/init.d/iscsi
stop
# /etc/init.d/iscsi
restart
After restarting service list the newly added block by lsblk
command and mount on a desire mount point.
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