Scsi-target-utils Quickstart Guide

About
This page is intended to outline a series of steps need to quickly get a scsi-target-utils based iSCSI software target working.

Most of these instructions can also be found in a README provided by the scsi-target-utils package (see ).

Installation
Start by installing the package.


 * 1) yum install scsi-target-utils

Firewall
Ensure, port 3260 is available for incoming connection and there is no firewall in the way between target and test machine.


 * Either stop your firewall: # service iptables stop
 * Or, open up port 3260 for traffic using: # system-config-firewall
 * Or, modify your iptables configuration manually by
 * editing /etc/sysconfig/iptables
 * Then restarting iptables: # service iptables restart

Backing Store
When configured, the tgtd service will present a block device to iSCSI initiators. You may use a LVM logical volume, a disk partition, a whole disk, or a file. For production use a LVM logical volume is typically used. For this document, we will create a file.


 * 1) First, create a 8Gib file: # dd if=/dev/zero of=/tmp/iscsi-disk1 bs=1M count=8000

Service startup
Configure the tgtd service to start on boot. Type:


 * 1) service tgtd start
 * 2) chkconfig tgtd on

Up and running in 3 steps
For the fastest way to present a target device with 1 logical unit to any initiator ... follow these three steps:


 * 1) First, create a target device
 * 2) Next, add a logical unit
 * 3) Finally, enable the target to accept initiators

That's it!

How to ...
The following sections detail common actions you might perform using the tgtadm utility with the configuration used above. All of the following steps are also detailed in the README.iscsi included in the scsi-target-utils package.

List active targets
At any time you can list the active targets by typing: # tgtadm --lld iscsi --mode target --op show

Create a new target device
Create a target device: # tgtadm --lld iscsi --mode target --op new --tid=1 --targetname iqn.2009-02.com.example:for.all

Add a logical unit (LUN)
You can add a logical unit to an existing target device by typing:


 * 1) tgtadm --lld iscsi --mode logicalunit --op new --tid 1 --lun 1 -b /tmp/iscsi-disk1

Repeat this process while changing the -b parameter to add more logical units.

Permissions
The following sections detail various authentication and restrictions you can enabled using tgtadm.

List all user accounts
To display a list of all configured user accounts, type:
 * 1) tgtadm --lld iscsi --mode account --op show

Add IP wildcard to allow all initiators

 * 1) tgtadm --lld iscsi --mode target --op bind --tid 1 -I ALL

IP-based restrictions
If you've previously configured this target to accept ALL initiators, you'll need to remove that first.


 * 1) tgtadm --lld iscsi --mode target --op unbind --tid 1 -I ALL

Now, restrict access to a specific IP ...


 * 1) tgtadm --lld iscsi --mode target --op bind --tid 1 -I 10.10.0.24

Or, restrict access to a subnet ...


 * 1) tgtadm --lld iscsi --mode target --op bind --tid 1 -I 10.10.0.0/24

User/Password authentication (CHAP)
There are two types of CHAP configurations supported for iSCSI authentication:


 * Initiator Authentication is basic CHAP authentication. A username and password is created on the target.  Each initiator logs into the target with this information.


 * Target Authentication is an authentication method in addition to Initiator Authentication. A separate "outgoing" username is created on the target.  This username/password pair is used by the target to log into each initiator.  Initiator Authentication must also be configured in this scenario.

CHAP Initiator Authentication

 * 1) First, create a user and password: # tgtadm --lld iscsi --mode account --op new --user consumer --password Longsw0rd
 * 2) Next, add the users to an existing target device: # tgtadm --lld iscsi --mode account --op bind --tid 1 --user consumer
 * 3) On the initiator's system, this username/password information is entered into  as:
 * 4) * For discovery authentication (not supported by tgt yet): discovery.sendtargets.auth.{username,password}
 * 5) * For session authentication: node.session.auth.{username,password}

CHAP Target Authentication

 * 1) First, create a user and password: # tgtadm --lld iscsi --mode account --op new --user provider --password Shortsw0rd
 * 2) Next, add the users to an existing target device: # tgtadm --lld iscsi --mode account --op bind --tid 1 --user provider --outgoing
 * 3) On the initiator's system, this username/password information is entered into  as:
 * 4) * For discovery authentication (not supported by tgt yet): discovery.sendtargets.auth.{username_in,password_in}
 * 5) * For session authentication: node.session.auth.{username_in,password_in}