Centralized Secure Storage (iSCSI) – “Initiator Client” Setup on RHEL/CentOS/Fedora – Part III

iSCSI Initiator are the clients which use to authenticated with iSCSI target servers to access the LUNs shared from target server. We can deploy any kind of Operating systems in those locally mounted Disks, just a single package need to be install to get authenticate with target server.

Client Initiator Setup
Client Initiator Setup

Features

  1. Can handle any kind of file systems in locally mounted Disk.
  2. No need of restating the system after partition using fdisk.

Requirements

  1. Create Centralized Secure Storage using iSCSI Target – Part 1
  2. Create LUN’s using LVM in Target Server – Part 2
My Client Setup for Initiator
  1. Operating System – CentOS release 6.5 (Final)
  2. iSCSI Target IP – 192.168.0.50
  3. Ports Used : TCP 3260

Warning: Never stop the service while LUNs Mounted in Client machines (Initiator).

Initiator Client Setup

1. In Client side, we need to install the package ‘iSCSI-initiator-utils‘, search for the package using following command.

# 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

2. Once you locate the package, just install the initiator package using yum command as shown.

# 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
man iscsiadm
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

5. Here we got the iSCSI (iqn) qualified name from above command execution.

192.168.0.200:3260,1 iqn.2014-07.com.tecmint:tgt1
Discover Target
Discover Target

6. To log-in use the below command to attach the LUN to our local System, this will authenticate with target server and allow us to log-in into LUN.

# iscsiadm --mode node --targetname iqn.2014-07.com.tecmint:tgt1 --portal 192.168.0.200:3260 --login
Login To Target Server
Login To Target Server

Note: Use the login command and replace login with logout at end of command.

# iscsiadm --mode node --targetname iqn.2014-07.com.tecmint:tgt1 --portal 192.168.0.200:3260 --logout
Logout from Target Server
Logout from Target Server

7. After login to the LUN, list the records of Node using.

# iscsiadm --mode node
List Node
List Node

8. Display all data of a particular node.

# iscsiadm --mode node --targetname iqn.2014-07.com.tecmint:tgt1 --portal 192.168.0.200:3260
Sample Output
# BEGIN RECORD 6.2.0-873.10.el6
node.name = iqn.2014-07.com.tecmint:tgt1
node.tpgt = 1
node.startup = automatic
node.leading_login = No
iface.hwaddress = <empty>
iface.ipaddress = <empty>
iface.iscsi_ifacename = default
iface.net_ifacename = <empty>
iface.transport_name = tcp
iface.initiatorname = <empty>
iface.bootproto = <empty>
iface.subnet_mask = <empty>
iface.gateway = <empty>
iface.ipv6_autocfg = <empty>
iface.linklocal_autocfg = <empty>
....

9. Then list the drive using, fdisk will list every authenticated disks.

# fdisk -l /dev/sda
List Disks
List Disks

10. Run fdisk to create a new partition.

# fdisk -cu /dev/sda
Create New Partition
Create New Partition

Note: After Creating a Partition using fdisk, we don’t need to reboot, as we used to do in our local systems, Because this is a remote shared storage mounted locally.

11. Format the newly created partition.

# mkfs.ext4 /dev/sda1
Format New Partition
Format New Partition

12. Create a Directory and mount the formatted partition.

# mkdir /mnt/iscsi_share
# mount /dev/sda1 /mnt/iscsi_share/
# ls -l /mnt/iscsi_share/
Mount New Partition
Mount New Partition

13. List the Mount Points.

 
# df -Th
  1. -T – Prints files system types.
  2. -h – Prints in human readable format eg : Megabyte or Gigabyte.
List New Partition
List New Partition

14. If we need to permanently mount the Drive use fstab entry.

# vim /etc/fstab

15.Append the following Entry in fstab.

/dev/sda1  /mnt/iscsi_share/   ext4    defaults,_netdev   0 0

Note: Use _netdev in fstab, as this is a network device.

Auto Mount Partition
Auto Mount Partition

16. Finally check whether our fstab entry have any error.

# mount -av
  1. -a – all mount point
  2. -v – Verbose
Verify fstab Entries
Verify fstab Entries

We have Completed Our client side configuration Successfully. Start to use the drive as we use our local system disk.

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32 thoughts on “Centralized Secure Storage (iSCSI) – “Initiator Client” Setup on RHEL/CentOS/Fedora – Part III”

  1. Thank you very much for your posts, I have learned so much from you and it is very kind of you to offer all this valuable knowledge for free. Many thanks again :-)

    Reply
  2. Hi,

    Thanks for your article. I am facing a problem in following command ” iscsiadm –mode node –targetname iqn.2015-02.com.example:target01 –portal 10.129.154.77:3260 –login” It says login successful but fdisk -l not showing any disk(iscsi target disk). Kindly help me……

    Reply
  3. thanks for this publication. But I am having a situation ehen i run the following command it says no record found, but in your presentation it produced result.
    iscsiadm –mode node –targetname iqn.2015-01.com.tecmint:tgt1 –portal 172.110.0.200:3260

    Also, when I run the fdisk -l /dev/sdb, it only show one partition, but in you presentation it showed 4 partition. Is there any reason for that or I am doing something wrong. Please help me out. Thanks

    Reply
  4. @ gaurav # iscsiadm –mode node –targetname iqn.2014-07.com.tecmint:tgt1 –portal 192.168.0.200:3260 –login

    192.168.0.0 this is my network range. may be your network range will be 192.168.1.0, replace with your range.

    # iscsiadm –mode node –targetname iqn.2014-07.com.tecmint:tgt1 –portal 192.168.1.200:3260 –login

    Please change the IP address as per your need before installing and configure.

    Reply
  5. sir thanku for the post. i am facing a problem int the following command:

    # iscsiadm –mode node –targetname iqn.2014-07.com.tecmint:tgt1 –portal 192.168.0.200:3260 –login

    the initiator is unable to locate the target server and is displaying the message
    cannot route to host. are there any changes needed to be done in the network settings?

    Reply
  6. @ Omipenguin your server setup seems working fine. Never restart the iscsiadm, While discovery it will automatically start the service after that we don’t need to restart the service if so we will get disconnect from the shared LUN. Please have a look at Step 5. do chkconfig no need of adding in rc.local, LUN is a RAW disk shared from a iSCSI server so we can create standard or LVM too. seems your steps may have issue, could you please give us the steps what you following after the discovery ? fstab entry

    Happy to help you…

    Reply
  7. Thanks Tut was great. But I faced issue. I shared 8GB LUN from ServerA and I can see the LUN on ServerB using both “fdisk -l” and “ls -l /dev/disk/by-path”

    I created LVM on this Partition and added its entry in fstab and everything’s working till system in not restart. When i restart the system booya Volume group gone. Even though LUN is appearing in fdisk -l

    I set the iscsi and iscid on autostart and added the “icsciadm –discover and –login ” in rc.local. But still not working everytime I create the Partition or LVM on this drive and restart the system its not there.

    Reply
  8. Hi,

    great article….. and waiting for some more useful information from your side. i have done this scenario in lab. Is there any big challenge when in live scenario?

    Reply

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