Table of Contents
This chapter teaches you how to setup an iSCSI target server and an iSCSI initiator client.
iSCSI is a protocol that enables SCSI over IP. This means that you can have local SCSI devices (like /dev/sdb) without having the storage hardware in the local computer.
The computer holding the physical storage hardware is called the iSCSI Target. Each individual addressable iSCSI device on the target server will get a LUN number.
The iSCSI client computer that is connecting to the Target server is called an Initiator. An initiator will send SCSI commands over IP instead of directly to the hardware. The Initiator will connect to the Target.
This section will describe iSCSI Target setup on RHEL6, RHEL7 and CentOS.
Start with installing the iSCSI Target package.
yum install scsi-target-utils
We configure three local disks in /etc/tgt/targets.conf to become three LUN's.
<target iqn.2008-09.com.example:server.target2>
direct-store /dev/sdb
direct-store /dev/sdc
direct-store /dev/sdd
incominguser paul hunter2
</target>Restart the service.
[root@centos65 ~]# service tgtd start Starting SCSI target daemon: [ OK ]
The standard local port for iSCSI Target is 3260, in case of doubt you can verify this with netstat.
[root@server1 tgt]# netstat -ntpl | grep tgt tcp 0 0 0.0.0.0:3260 0.0.0.0:* LISTEN 1670/tgtd tcp 0 0 :::3260 :::* LISTEN 1670/tgtd
The tgt-admin -s command should now give you a nice overview of the three LUN's (and also LUN 0 for the controller).
[root@server1 tgt]# tgt-admin -s
Target 1: iqn.2014-04.be.linux-training:server1.target1
System information:
Driver: iscsi
State: ready
I_T nexus information:
LUN information:
LUN: 0
Type: controller
SCSI ID: IET 00010000
SCSI SN: beaf10
Size: 0 MB, Block size: 1
Online: Yes
Removable media: No
Prevent removal: No
Readonly: No
Backing store type: null
Backing store path: None
Backing store flags:
LUN: 1
Type: disk
SCSI ID: IET 00010001
SCSI SN: VB9f23197b-af6cfb60
Size: 1074 MB, Block size: 512
Online: Yes
Removable media: No
Prevent removal: No
Readonly: No
Backing store type: rdwr
Backing store path: /dev/sdb
Backing store flags:
LUN: 2
Type: disk
SCSI ID: IET 00010002
SCSI SN: VB8f554351-a1410828
Size: 1074 MB, Block size: 512
Online: Yes
Removable media: No
Prevent removal: No
Readonly: No
Backing store type: rdwr
Backing store path: /dev/sdc
Backing store flags:
LUN: 3
Type: disk
SCSI ID: IET 00010003
SCSI SN: VB1035d2f0-7ae90b49
Size: 1074 MB, Block size: 512
Online: Yes
Removable media: No
Prevent removal: No
Readonly: No
Backing store type: rdwr
Backing store path: /dev/sdd
Backing store flags:
Account information:
ACL information:
ALLThis section will describe iSCSI Initiator setup on RHEL6, RHEL7 and CentOS.
Start with installing the iSCSI Initiator package.
[root@server2 ~]# yum install iscsi-initiator-utils
Then ask the iSCSI target server to send you the target names.
[root@server2 ~]# iscsiadm -m discovery -t sendtargets -p 192.168.1.95:3260 Starting iscsid: [ OK ] 192.168.1.95:3260,1 iqn.2014-04.be.linux-training:centos65.target1
We received iqn.2014-04.be.linux-training:centos65.target1.
We use this iqn to configure the username and the password (paul and hunter2) that we set on the target server.
[root@server2 iscsi]# iscsiadm -m node --targetname iqn.2014-04.be.linux-tra\ ining:centos65.target1 --portal "192.168.1.95:3260" --op=update --name node.\ session.auth.username --value=paul [root@server2 iscsi]# iscsiadm -m node --targetname iqn.2014-04.be.linux-tra\ ining:centos65.target1 --portal "192.168.1.95:3260" --op=update --name node.\ session.auth.password --value=hunter2 [root@server2 iscsi]# iscsiadm -m node --targetname iqn.2014-04.be.linux-tra\ ining:centos65.target1 --portal "192.168.1.95:3260" --op=update --name node.\ session.auth.authmethod --value=CHAP
RHEL and CentOS will store these in /var/lib/iscsi/nodes/.
[root@server2 iscsi]# grep auth /var/lib/iscsi/nodes/iqn.2014-04.be.linux-tr\ aining\:centos65.target1/192.168.1.95\,3260\,1/default node.session.auth.authmethod = CHAP node.session.auth.username = paul node.session.auth.password = hunter2 node.conn[0].timeo.auth_timeout = 45 [root@server2 iscsi]#
A restart of the iscsi service will add three new devices to our system.
[root@server2 iscsi]# fdisk -l | grep Disk Disk /dev/sda: 42.9 GB, 42949672960 bytes Disk identifier: 0x0004f229 Disk /dev/sdb: 1073 MB, 1073741824 bytes Disk identifier: 0x00000000 Disk /dev/sdc: 1073 MB, 1073741824 bytes Disk identifier: 0x00000000 Disk /dev/sdd: 1073 MB, 1073741824 bytes Disk identifier: 0x00000000 Disk /dev/sde: 2147 MB, 2147483648 bytes Disk identifier: 0x00000000 Disk /dev/sdf: 2147 MB, 2147483648 bytes Disk identifier: 0x00000000 Disk /dev/sdg: 2147 MB, 2147483648 bytes Disk identifier: 0x00000000 Disk /dev/mapper/VolGroup-lv_root: 41.4 GB, 41448112128 bytes Disk identifier: 0x00000000 Disk /dev/mapper/VolGroup-lv_swap: 973 MB, 973078528 bytes Disk identifier: 0x00000000 [root@server2 iscsi]# service iscsi restart Stopping iscsi: [ OK ] Starting iscsi: [ OK ] [root@server2 iscsi]# fdisk -l | grep Disk Disk /dev/sda: 42.9 GB, 42949672960 bytes Disk identifier: 0x0004f229 Disk /dev/sdb: 1073 MB, 1073741824 bytes Disk identifier: 0x00000000 Disk /dev/sdc: 1073 MB, 1073741824 bytes Disk identifier: 0x00000000 Disk /dev/sdd: 1073 MB, 1073741824 bytes Disk identifier: 0x00000000 Disk /dev/sde: 2147 MB, 2147483648 bytes Disk identifier: 0x00000000 Disk /dev/sdf: 2147 MB, 2147483648 bytes Disk identifier: 0x00000000 Disk /dev/sdg: 2147 MB, 2147483648 bytes Disk identifier: 0x00000000 Disk /dev/mapper/VolGroup-lv_root: 41.4 GB, 41448112128 bytes Disk identifier: 0x00000000 Disk /dev/mapper/VolGroup-lv_swap: 973 MB, 973078528 bytes Disk identifier: 0x00000000 Disk /dev/sdh: 1073 MB, 1073741824 bytes Disk identifier: 0x00000000 Disk /dev/sdi: 1073 MB, 1073741824 bytes Disk identifier: 0x00000000 Disk /dev/sdj: 1073 MB, 1073741824 bytes Disk identifier: 0x00000000
You can verify iscsi status with:
service iscsi status
Installing the software for the target server requires iscsitarget on Ubuntu and Debian, and an extra iscsitarget-dkms for the kernel modules only on Debian.
root@debby6:~# aptitude install iscsitarget The following NEW packages will be installed: iscsitarget 0 packages upgraded, 1 newly installed, 0 to remove and 0 not upgraded. Need to get 69.4 kB of archives. After unpacking 262 kB will be used. Get:1 http://ftp.belnet.be/debian/ squeeze/main iscsitarget i386 1.4.20.2-1\ [69.4 kB] Fetched 69.4 kB in 0s (415 kB/s) Selecting previously deselected package iscsitarget. (Reading database ... 36441 files and directories currently installed.) Unpacking iscsitarget (from .../iscsitarget_1.4.20.2-1_i386.deb) ... Processing triggers for man-db ... Setting up iscsitarget (1.4.20.2-1) ... iscsitarget not enabled in "/etc/default/iscsitarget", not starting...(warning).
On Debian 6 you will also need aptitude install iscsitarget-dkms for the kernel modules, on Debian 5 this is aptitude install iscsitarget-modules-`uname -a`. Ubuntu includes the kernel modules in the main package.
The iSCSI target server is disabled by default, so we enable it.
root@debby6:~# cat /etc/default/iscsitarget ISCSITARGET_ENABLE=false root@debby6:~# vi /etc/default/iscsitarget root@debby6:~# cat /etc/default/iscsitarget ISCSITARGET_ENABLE=true
You can use LVM volumes (/dev/md0/lvol0), physical partitions (/dev/sda) ,raid devices (/dev/md0) or just plain files for storage. In this demo, we use files created with dd.
This screenshot shows how to create three small files (100MB, 200MB and 300MB).
root@debby6:~# mkdir /iscsi root@debby6:~# dd if=/dev/zero of=/iscsi/lun1.img bs=1M count=100 100+0 records in 100+0 records out 104857600 bytes (105 MB) copied, 0.315825 s, 332 MB/s root@debby6:~# dd if=/dev/zero of=/iscsi/lun2.img bs=1M count=200 200+0 records in 200+0 records out 209715200 bytes (210 MB) copied, 1.08342 s, 194 MB/s root@debby6:~# dd if=/dev/zero of=/iscsi/lun3.img bs=1M count=300 300+0 records in 300+0 records out 314572800 bytes (315 MB) copied, 1.36209 s, 231 MB/s
We need to declare these three files as iSCSI targets in /etc/iet/ietd.conf (used to be /etc/ietd.conf).
root@debby6:/etc/iet# cp ietd.conf ietd.conf.original root@debby6:/etc/iet# > ietd.conf root@debby6:/etc/iet# vi ietd.conf root@debby6:/etc/iet# cat ietd.conf Target iqn.2010-02.be.linux-training:storage.lun1 IncomingUser isuser hunter2 OutgoingUser Lun 0 Path=/iscsi/lun1.img,Type=fileio Alias LUN1 Target iqn.2010-02.be.linux-training:storage.lun2 IncomingUser isuser hunter2 OutgoingUser Lun 0 Path=/iscsi/lun2.img,Type=fileio Alias LUN2 Target iqn.2010-02.be.linux-training:storage.lun3 IncomingUser isuser hunter2 OutgoingUser Lun 0 Path=/iscsi/lun3.img,Type=fileio Alias LUN3
We also need to add our devices to the /etc/initiators.allow file.
root@debby6:/etc/iet# cp initiators.allow initiators.allow.original root@debby6:/etc/iet# >initiators.allow root@debby6:/etc/iet# vi initiators.allow root@debby6:/etc/iet# cat initiators.allow iqn.2010-02.be.linux-training:storage.lun1 iqn.2010-02.be.linux-training:storage.lun2 iqn.2010-02.be.linux-training:storage.lun3
Time to start the server now:
root@debby6:/etc/iet# /etc/init.d/iscsitarget start Starting iSCSI enterprise target service:. . root@debby6:/etc/iet#
Verify activation of the storage devices in /proc/net/iet:
root@debby6:/etc/iet# cat /proc/net/iet/volume tid:3 name:iqn.2010-02.be.linux-training:storage.lun3 lun:0 state:0 iotype:fileio iomode:wt blocks:614400 blocksize:\ 512 path:/iscsi/lun3.img tid:2 name:iqn.2010-02.be.linux-training:storage.lun2 lun:0 state:0 iotype:fileio iomode:wt blocks:409600 blocksize:\ 512 path:/iscsi/lun2.img tid:1 name:iqn.2010-02.be.linux-training:storage.lun1 lun:0 state:0 iotype:fileio iomode:wt blocks:204800 blocksize:\ 512 path:/iscsi/lun1.img root@debby6:/etc/iet# cat /proc/net/iet/session tid:3 name:iqn.2010-02.be.linux-training:storage.lun3 tid:2 name:iqn.2010-02.be.linux-training:storage.lun2 tid:1 name:iqn.2010-02.be.linux-training:storage.lun1
First we install the iSCSi client software (on another computer than the target).
root@ubu1104:~# aptitude install open-iscsi
Reading package lists... Done
Building dependency tree
Reading state information... Done
Reading extended state information
Initializing package states... Done
The following NEW packages will be installed:
open-iscsi open-iscsi-utils{a}Then we set the iSCSI client to start automatically.
root@ubu1104:/etc/iscsi# cp iscsid.conf iscsid.conf.original root@ubu1104:/etc/iscsi# vi iscsid.conf root@ubu1104:/etc/iscsi# grep ^node.startup iscsid.conf node.startup = automatic
Or you could start it manually.
root@ubu1104:/etc/iscsi/nodes# /etc/init.d/open-iscsi start * Starting iSCSI initiator service iscsid [ OK ] * Setting up iSCSI targets [ OK ] root@ubu1104:/etc/iscsi/nodes#
Now we can connect to the Target server and use iscsiadm to discover the devices it offers:
root@ubu1104:/etc/iscsi# iscsiadm -m discovery -t st -p 192.168.1.31 192.168.1.31:3260,1 iqn.2010-02.be.linux-training:storage.lun2 192.168.1.31:3260,1 iqn.2010-02.be.linux-training:storage.lun1 192.168.1.31:3260,1 iqn.2010-02.be.linux-training:storage.lun3
We can use the same iscsiadm to edit the files in /etc/iscsi/nodes/.
root@ubu1104:/etc/iscsi# iscsiadm -m node --targetname "iqn.2010-02.be.linu\ x-training:storage.lun1" --portal "192.168.1.31:3260" --op=update --name no\ de.session.auth.authmethod --value=CHAP root@ubu1104:/etc/iscsi# iscsiadm -m node --targetname "iqn.2010-02.be.linu\ x-training:storage.lun1" --portal "192.168.1.31:3260" --op=update --name no\ de.session.auth.username --value=isuser root@ubu1104:/etc/iscsi# iscsiadm -m node --targetname "iqn.2010-02.be.linu\ x-training:storage.lun1" --portal "192.168.1.31:3260" --op=update --name no\ de.session.auth.password --value=hunter2
Repeat the above for the other two devices.
Restart the initiator service to log in to the target.
root@ubu1104:/etc/iscsi/nodes# /etc/init.d/open-iscsi restart * Disconnecting iSCSI targets [ OK ] * Stopping iSCSI initiator service [ OK ] * Starting iSCSI initiator service iscsid [ OK ] * Setting up iSCSI targets
Use fdisk -l to enjoy three new iSCSI devices.
root@ubu1104:/etc/iscsi/nodes# fdisk -l 2> /dev/null | grep Disk Disk /dev/sda: 17.2 GB, 17179869184 bytes Disk identifier: 0x0001983f Disk /dev/sdb: 209 MB, 209715200 bytes Disk identifier: 0x00000000 Disk /dev/sdd: 314 MB, 314572800 bytes Disk identifier: 0x00000000 Disk /dev/sdc: 104 MB, 104857600 bytes Disk identifier: 0x00000000
The Target (the server) now shows active sessions.
root@debby6:/etc/iet# cat /proc/net/iet/session tid:3 name:iqn.2010-02.be.linux-training:storage.lun3 sid:5348024611832320 initiator:iqn.1993-08.org.debian:01:8983ed2d770 cid:0 ip:192.168.1.35 state:active hd:none dd:none tid:2 name:iqn.2010-02.be.linux-training:storage.lun2 sid:4785074624856576 initiator:iqn.1993-08.org.debian:01:8983ed2d770 cid:0 ip:192.168.1.35 state:active hd:none dd:none tid:1 name:iqn.2010-02.be.linux-training:storage.lun1 sid:5066549618344448 initiator:iqn.1993-08.org.debian:01:8983ed2d770 cid:0 ip:192.168.1.35 state:active hd:none dd:none root@debby6:/etc/iet#
There is no difference between using SCSI or iSCSI devices once they are connected : partition, make filesystem, mount.
root@ubu1104:/etc/iscsi/nodes# history | tail -13 94 fdisk /dev/sdc 95 fdisk /dev/sdd 96 fdisk /dev/sdb 97 mke2fs /dev/sdb1 98 mke2fs -j /dev/sdc1 99 mkfs.ext4 /dev/sdd1 100 mkdir /mnt/is1 101 mkdir /mnt/is2 102 mkdir /mnt/is3 103 mount /dev/sdb1 /mnt/is1 104 mount /dev/sdc1 /mnt/is2 105 mount /dev/sdd1 /mnt/is3 106 history | tail -13 root@ubu1104:/etc/iscsi/nodes# mount | grep is /dev/sdb1 on /mnt/is1 type ext2 (rw) /dev/sdc1 on /mnt/is2 type ext3 (rw) /dev/sdd1 on /mnt/is3 type ext4 (rw)
The prefered tool to setup an iSCSI Target on RHEL is targetcli.
[root@centos7 ~]# yum install targetcli
Loaded plugins: fastestmirror
...
...
Installed:
targetcli.noarch 0:2.1.fb37-3.el7
Complete!
[root@centos7 ~]#The targetcli tool is interactive and represents the configuration fo the target in a structure that resembles a directory tree with several files. Although this is explorable inside targetcli with ls, cd and pwd, this are not files on the file system.
This tool also has tab-completion, which is very handy for the iqn names.
[root@centos7 ~]# targetcli targetcli shell version 2.1.fb37 Copyright 2011-2013 by Datera, Inc and others. For help on commands, type 'help'. /> cd backstores/ /backstores> ls o- backstores ............................................................ [...] o- block ................................................ [Storage Objects: 0] o- fileio ............................................... [Storage Objects: 0] o- pscsi ................................................ [Storage Objects: 0] o- ramdisk .............................................. [Storage Objects: 0] /backstores> cd block /backstores/block> ls o- block .................................................. [Storage Objects: 0] /backstores/block> create server1.disk1 /dev/sdb Created block storage object server1.disk1 using /dev/sdb. /backstores/block> ls o- block .................................................. [Storage Objects: 1] o- server1.disk1 .................. [/dev/sdb (2.0GiB) write-thru deactivated] /backstores/block> cd /iscsi /iscsi> create iqn.2015-04.be.linux:iscsi1 Created target iqn.2015-04.be.linux:iscsi1. Created TPG 1. Global pref auto_add_default_portal=true Created default portal listening on all IPs (0.0.0.0), port 3260. /iscsi> cd /iscsi/iqn.2015-04.be.linux:iscsi1/tpg1/acls /iscsi/iqn.20...si1/tpg1/acls> create iqn.2015-04.be.linux:server2 Created Node ACL for iqn.2015-04.be.linux:server2 /iscsi/iqn.20...si1/tpg1/acls> cd iqn.2015-04.be.linux:server2 /iscsi/iqn.20...linux:server2> set auth userid=paul Parameter userid is now 'paul'. /iscsi/iqn.20...linux:server2> set auth password=hunter2 Parameter password is now 'hunter2'. /iscsi/iqn.20...linux:server2> cd /iscsi/iqn.2015-04.be.linux:iscsi1/tpg1/luns /iscsi/iqn.20...si1/tpg1/luns> create /backstores/block/server1.disk1 Created LUN 0. Created LUN 0->0 mapping in node ACL iqn.2015-04.be.linux:server2 s/scsi/iqn.20...si1/tpg1/luns> cd /iscsi/iqn.2015-04.be.linux:iscsi1/tpg1/portals /iscsi/iqn.20.../tpg1/portals> create 192.168.1.128 Using default IP port 3260 Could not create NetworkPortal in configFS. /iscsi/iqn.20.../tpg1/portals> cd / /> ls o- / ..................................................................... [...] o- backstores .......................................................... [...] | o- block .............................................. [Storage Objects: 1] | | o- server1.disk1 ................ [/dev/sdb (2.0GiB) write-thru activated] | o- fileio ............................................. [Storage Objects: 0] | o- pscsi .............................................. [Storage Objects: 0] | o- ramdisk ............................................ [Storage Objects: 0] o- iscsi ........................................................ [Targets: 1] | o- iqn.2015-04.be.linux:iscsi1 ................................... [TPGs: 1] | o- tpg1 ........................................... [no-gen-acls, no-auth] | o- acls ...................................................... [ACLs: 1] | | o- iqn.2015-04.be.linux:server2 ..................... [Mapped LUNs: 1] | | o- mapped_lun0 ..................... [lun0 block/server1.disk1 (rw)] | o- luns ...................................................... [LUNs: 1] | | o- lun0 ............................. [block/server1.disk1 (/dev/sdb)] | o- portals ................................................ [Portals: 1] | o- 0.0.0.0:3260 ................................................. [OK] o- loopback ..................................................... [Targets: 0] /> saveconfig Last 10 configs saved in /etc/target/backup. Configuration saved to /etc/target/saveconfig.json /> exit Global pref auto_save_on_exit=true Last 10 configs saved in /etc/target/backup. Configuration saved to /etc/target/saveconfig.json [root@centos7 ~]#
Use the systemd tools to manage the service:
[root@centos7 ~]# systemctl enable target ln -s '/usr/lib/systemd/system/target.service' '/etc/systemd/system/multi-user.target.wants/target.service' [root@centos7 ~]# systemctl start target [root@centos7 ~]#
Depending on your organisations policy, you may need to configure firewall and SELinux. The screenshot belows adds a firewall rule to allow all traffic over port 3260, and disables SELinux.
[root@centos7 ~]# firewall-cmd --permanent --add-port=3260/tcp [root@centos7 ~]# firewall-cmd --reload [root@centos7 ~]# setenforce 0
The total configuration is visible using ls from the root.
[root@centos7 ~]# targetcli targetcli shell version 2.1.fb37 Copyright 2011-2013 by Datera, Inc and others. For help on commands, type 'help'. /> ls o- / ..................................................................... [...] o- backstores .......................................................... [...] | o- block .............................................. [Storage Objects: 1] | | o- server1.disk1 ................ [/dev/sdb (2.0GiB) write-thru activated] | o- fileio ............................................. [Storage Objects: 0] | o- pscsi .............................................. [Storage Objects: 0] | o- ramdisk ............................................ [Storage Objects: 0] o- iscsi ........................................................ [Targets: 1] | o- iqn.2015-04.be.linux:iscsi1 ................................... [TPGs: 1] | o- tpg1 ........................................... [no-gen-acls, no-auth] | o- acls ...................................................... [ACLs: 1] | | o- iqn.2015-04.be.linux:server2 ..................... [Mapped LUNs: 1] | | o- mapped_lun0 ..................... [lun0 block/server1.disk1 (rw)] | o- luns ...................................................... [LUNs: 1] | | o- lun0 ............................. [block/server1.disk1 (/dev/sdb)] | o- portals ................................................ [Portals: 1] | o- 0.0.0.0:3260 ................................................. [OK] o- loopback ..................................................... [Targets: 0] /> /> exit Global pref auto_save_on_exit=true Last 10 configs saved in /etc/target/backup. Configuration saved to /etc/target/saveconfig.json [root@centos7 ~]#
The iSCSI Target is now ready.
This is identical to the RHEL6/CentOS6 procedure:
[root@centos7 ~]# yum install iscsi-initiator-utils
Loaded plugins: fastestmirror
...
...
Installed:
iscsi-initiator-utils.x86_64 0:6.2.0.873-29.el7
Dependency Installed:
iscsi-initiator-utils-iscsiuio.x86_64 0:6.2.0.873-29.el7
Complete!Map your initiator name to the targetcli acl.
[root@centos7 ~]# cat /etc/iscsi/initiatorname.iscsi
InitiatorName=iqn.2015-04.be.linux:server2
[root@centos7 ~]#Enter the CHAP authentication in /etc/iscsi/iscsid.conf.
[root@centos7 ~]# vi /etc/iscsi/iscsid.conf ... [root@centos7 ~]# grep ^node.session.auth /etc/iscsi/iscsid.conf node.session.auth.authmethod = CHAP node.session.auth.username = paul node.session.auth.password = hunter2 [root@centos7 ~]#
There are no extra devices yet...
[root@centos7 ~]# fdisk -l | grep sd
Disk /dev/sda: 22.0 GB, 22038806528 bytes, 43044544 sectors
/dev/sda1 * 2048 1026047 512000 83 Linux
/dev/sda2 1026048 43042815 21008384 8e Linux LVM
Disk /dev/sdb: 2147 MB, 2147483648 bytes, 4194304 sectorsEnable the service and discover the target.
[root@centos7 ~]# systemctl enable iscsid ln -s '/usr/lib/systemd/system/iscsid.service' '/etc/systemd/system/multi-user.target.wants/iscsid.service' [root@centos7 ~]# iscsiadm -m discovery -t st -p 192.168.1.128 192.168.1.128:3260,1 iqn.2015-04.be.linux:iscsi1
Log into the target and see /dev/sdc appear.
[root@centos7 ~]# iscsiadm -m node -T iqn.2015-04.be.linux:iscsi1 -p 192.168.1.128 -l Logging in to [iface: default, target: iqn.2015-04.be.linux:iscsi1, portal: 192.168.1.128,3260] (multiple) Login to [iface: default, target: iqn.2015-04.be.linux:iscsi1, portal: 192.168.1.128,3260] successful. [root@centos7 ~]# [root@centos7 ~]# fdisk -l | grep sd Disk /dev/sda: 22.0 GB, 22038806528 bytes, 43044544 sectors /dev/sda1 * 2048 1026047 512000 83 Linux /dev/sda2 1026048 43042815 21008384 8e Linux LVM Disk /dev/sdb: 2147 MB, 2147483648 bytes, 4194304 sectors Disk /dev/sdc: 2147 MB, 2147483648 bytes, 4194304 sectors [root@centos7 ~]#
1. Set up a target (using an LVM and a SCSI device) and an initiator that connects to both.
2. Set up an iSCSI Target and Initiator on two CentOS7/RHEL7 computers with the following information:
Table 12.1. iSCSI Target and Initiator practice
| variable | value |
|---|---|
| Target Server IP | |
| shared devices on target | /dev/sd /dev/sd /dev/sd |
| shared device name sd | |
| shared device name sd | |
| shared device name sd | |
| target iqn | |
| initiator iqn | |
| username | |
| password |
1. Set up a target (using an LVM and a SCSI device) and an initiator that connects to both.
This solution was done on Debian/ubuntu/Mint. For RHEL/CentOS check the theory.
Decide (with a partner) on a computer to be the Target and another computer to be the Initiator.
On the Target computer:
First install iscsitarget using the standard tools for installing software in your distribution. Then use your knowledge from the previous chapter to setup a logical volume (/dev/vg/lvol0) and use the RAID chapter to setup /dev/md0. Then perform the following step:
vi /etc/default/iscsitarget (set enable to true)
Add your devices to /etc/iet/ietf.conf
root@debby6:/etc/iet# cat ietd.conf Target iqn.2010-02.be.linux-training:storage.lun1 IncomingUser isuser hunter2 OutgoingUser Lun 0 Path=/dev/vg/lvol0,Type=fileio Alias LUN1 Target iqn.2010-02.be.linux-training:storage.lun2 IncomingUser isuser hunter2 OutgoingUser Lun 0 Path=/dev/md0,Type=fileio Alias LUN2
Add both devices to /etc/iet/initiators.allow
root@debby6:/etc/iet# cat initiators.allow iqn.2010-02.be.linux-training:storage.lun1 iqn.2010-02.be.linux-training:storage.lun2
Now start the iscsitarget daemon and move over to the Initiator.
On the Initiator computer:
Install open-iscsi and start the daemon.
Then use iscsiadm -m discovery -t st -p 'target-ip' to see the iscsi devices on the Target.
Edit the files /etc/iscsi/nodes/ as shown in the book. Then restart the iSCSI daemon and rund fdisk -l to see the iSCSI devices.
2. Set up an iSCSI Target and Initiator on two CentOS7/RHEL7 computers with the following information:
Table 12.2. iSCSI Target and Initiator practice
| variable | value |
|---|---|
| Target Server IP | 192.168.1.143 (Adjust for your subnet!) |
| shared devices on target | /dev/sdb /dev/sdc /dev/sdd |
| shared device name sdb | target.disk1 |
| shared device name sdc | target.disk2 |
| shared device name sdd | target.disk3 |
| target iqn | iqn.2015-04.be.linux:target |
| initiator iqn | iqn.2015-04.be.linux:initiator |
| username | paul |
| password | hunter2 |
On the iSCSI Target server:
[root@centos7 ~]# targetcli targetcli shell version 2.1.fb37 Copyright 2011-2013 by Datera, Inc and others. For help on commands, type 'help'. /> cd /backstores/block /backstores/block> ls o- block .................................................. [Storage Objects: 0] /backstores/block> create target.disk1 /dev/sdb Created block storage object target.disk1 using /dev/sdb. /backstores/block> create target.disk2 /dev/sdc Created block storage object target.disk2 using /dev/sdc. /backstores/block> create target.disk3 /dev/sdd Created block storage object target.disk3 using /dev/sdd. /backstores/block> ls o- block .................................................. [Storage Objects: 3] o- target.disk1 ................... [/dev/sdb (8.0GiB) write-thru deactivated] o- target.disk2 ................... [/dev/sdc (8.0GiB) write-thru deactivated] o- target.disk3 ................... [/dev/sdd (8.0GiB) write-thru deactivated] /backstores/block> cd /iscsi /iscsi> create iqn.2015-04.be.linux:target Created target iqn.2015-04.be.linux:target. Created TPG 1. Global pref auto_add_default_portal=true Created default portal listening on all IPs (0.0.0.0), port 3260. /iscsi> cd /iscsi/iqn.2015-04.be.linux:target/tpg1/acls /iscsi/iqn.20...get/tpg1/acls> create iqn.2015-04.be.linux:initiator Created Node ACL for iqn.2015-04.be.linux:initiator /iscsi/iqn.20...get/tpg1/acls> cd iqn.2015-04.be.linux:initiator /iscsi/iqn.20...nux:initiator> pwd /iscsi/iqn.2015-04.be.linux:target/tpg1/acls/iqn.2015-04.be.linux:initiator /iscsi/iqn.20...nux:initiator> set auth userid=paul Parameter userid is now 'paul'. /iscsi/iqn.20...nux:initiator> set auth password=hunter2 Parameter password is now 'hunter2'. /iscsi/iqn.20...nux:initiator> cd /iscsi/iqn.2015-04.be.linux:target/tpg1/ /iscsi/iqn.20...x:target/tpg1> ls o- tpg1 ................................................. [no-gen-acls, no-auth] o- acls ............................................................ [ACLs: 1] | o- iqn.2015-04.be.linux:initiator ......................... [Mapped LUNs: 0] o- luns ............................................................ [LUNs: 0] o- portals ...................................................... [Portals: 1] o- 0.0.0.0:3260 ....................................................... [OK] /iscsi/iqn.20...x:target/tpg1> cd luns /iscsi/iqn.20...get/tpg1/luns> create /backstores/block/target.disk1 Created LUN 0. Created LUN 0->0 mapping in node ACL iqn.2015-04.be.linux:initiator /iscsi/iqn.20...get/tpg1/luns> create /backstores/block/target.disk2 Created LUN 1. Created LUN 1->1 mapping in node ACL iqn.2015-04.be.linux:initiator /iscsi/iqn.20...get/tpg1/luns> create /backstores/block/target.disk3 Created LUN 2. Created LUN 2->2 mapping in node ACL iqn.2015-04.be.linux:initiator s/scsi/iqn.20...get/tpg1/luns> cd /iscsi/iqn.2015-04.be.linux:target/tpg1/portals /iscsi/iqn.20.../tpg1/portals> create 192.168.1.143 Using default IP port 3260 Could not create NetworkPortal in configFS. /iscsi/iqn.20.../tpg1/portals> cd / /> ls o- / ..................................................................... [...] o- backstores .......................................................... [...] | o- block .............................................. [Storage Objects: 3] | | o- target.disk1 ................. [/dev/sdb (8.0GiB) write-thru activated] | | o- target.disk2 ................. [/dev/sdc (8.0GiB) write-thru activated] | | o- target.disk3 ................. [/dev/sdd (8.0GiB) write-thru activated] | o- fileio ............................................. [Storage Objects: 0] | o- pscsi .............................................. [Storage Objects: 0] | o- ramdisk ............................................ [Storage Objects: 0] o- iscsi ........................................................ [Targets: 1] | o- iqn.2015-04.be.linux:target ................................... [TPGs: 1] | o- tpg1 ........................................... [no-gen-acls, no-auth] | o- acls ...................................................... [ACLs: 1] | | o- iqn.2015-04.be.linux:initiator ................... [Mapped LUNs: 3] | | o- mapped_lun0 ...................... [lun0 block/target.disk1 (rw)] | | o- mapped_lun1 ...................... [lun1 block/target.disk2 (rw)] | | o- mapped_lun2 ...................... [lun2 block/target.disk3 (rw)] | o- luns ...................................................... [LUNs: 3] | | o- lun0 .............................. [block/target.disk1 (/dev/sdb)] | | o- lun1 .............................. [block/target.disk2 (/dev/sdc)] | | o- lun2 .............................. [block/target.disk3 (/dev/sdd)] | o- portals ................................................ [Portals: 1] | o- 0.0.0.0:3260 ................................................. [OK] o- loopback ..................................................... [Targets: 0] /> exit Global pref auto_save_on_exit=true Last 10 configs saved in /etc/target/backup. Configuration saved to /etc/target/saveconfig.json [root@centos7 ~]# systemctl enable target ln -s '/usr/lib/systemd/system/target.service' '/etc/systemd/system/multi-user.target.wants/target.service' [root@centos7 ~]# systemctl start target [root@centos7 ~]# setenforce 0
On the Initiator:
[root@centos7 ~]# cat /etc/iscsi/initiatorname.iscsi InitiatorName=iqn.2015-04.be.linux:initiator [root@centos7 ~]# vi /etc/iscsi/iscsid.conf [root@centos7 ~]# grep ^node.session.au /etc/iscsi/iscsid.conf node.session.auth.authmethod = CHAP node.session.auth.username = paul node.session.auth.password = hunter2 [root@centos7 ~]# fdisk -l 2>/dev/null | grep sd Disk /dev/sda: 22.0 GB, 22038806528 bytes, 43044544 sectors /dev/sda1 * 2048 1026047 512000 83 Linux /dev/sda2 1026048 43042815 21008384 8e Linux LVM Disk /dev/sdb: 8589 MB, 8589934592 bytes, 16777216 sectors /dev/sdb1 2048 821247 409600 83 Linux /dev/sdb2 821248 1640447 409600 83 Linux /dev/sdb3 1640448 2459647 409600 83 Linux Disk /dev/sdc: 8589 MB, 8589934592 bytes, 16777216 sectors Disk /dev/sdd: 8589 MB, 8589934592 bytes, 16777216 sectors Disk /dev/sde: 2147 MB, 2147483648 bytes, 4194304 sectors Disk /dev/sdf: 2147 MB, 2147483648 bytes, 4194304 sectors [root@centos7 ~]# systemctl enable iscsid ln -s '/usr/lib/systemd/system/iscsid.service' '/etc/systemd/system/multi-user.target.wants/iscsid.service' [root@centos7 ~]# iscsiadm -m node -T iqn.2015-04.be.linux:target -p 192.168.1.143 -l Logging in to [iface: default, target: iqn.2015-04.be.linux:target, portal: 192.168.1.143,3260] (multiple) Login to [iface: default, target: iqn.2015-04.be.linux:target, portal: 192.168.1.143,3260] successful. [root@centos7 ~]# fdisk -l 2>/dev/null | grep sd Disk /dev/sda: 22.0 GB, 22038806528 bytes, 43044544 sectors /dev/sda1 * 2048 1026047 512000 83 Linux /dev/sda2 1026048 43042815 21008384 8e Linux LVM Disk /dev/sdb: 8589 MB, 8589934592 bytes, 16777216 sectors /dev/sdb1 2048 821247 409600 83 Linux /dev/sdb2 821248 1640447 409600 83 Linux /dev/sdb3 1640448 2459647 409600 83 Linux Disk /dev/sdc: 8589 MB, 8589934592 bytes, 16777216 sectors Disk /dev/sdd: 8589 MB, 8589934592 bytes, 16777216 sectors Disk /dev/sde: 2147 MB, 2147483648 bytes, 4194304 sectors Disk /dev/sdf: 2147 MB, 2147483648 bytes, 4194304 sectors Disk /dev/sdg: 8589 MB, 8589934592 bytes, 16777216 sectors Disk /dev/sdh: 8589 MB, 8589934592 bytes, 16777216 sectors Disk /dev/sdi: 8589 MB, 8589934592 bytes, 16777216 sectors [root@centos7 ~]#