✎ soc:2009:pravin:journal:bkodebianiscsi

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====== Booting debian over iscsi ======
Here I will be documenting my first attempt to boot linux over iscsi.

===== Reason to choose debian =====
  - Chose debian because the squashfs of debian works fine and there are no other problems.
  - Also, all the kernel modules needed for iscsi initiator are inside initramfs so, less work for me. :-)
  - No considerable success yet :-(

===== Installing the target =====
The target for these experiments is installed on my laptop (Ubuntu-9.04) with following procedure.
Most of these steps are taken from blog [[http://www.howtoforge.com/using-iscsi-on-ubuntu-9.04-initiator-and-target|Using iscsi over ubuntu 9.04]]\\

Installing iscsi target
<code>
sudo apt-get install iscsitarget
</code>

Configure the target by editing ''/etc/default/iscsitarget'', ''/etc/ietd.conf'' and ''/etc/initiators.allow'' files as follows\\

  - Open ''/etc/default/iscsitarget'' and set ''ISCSITARGET_ENABLE=true''
  - Open ''/etc/ietd.conf'', and comment out all lines, then add following paragraph
<code>
Target iqn.2001-04.com.example:storage.lun1
        IncomingUser 
        OutgoingUser
        Lun 0 Path=/var/www/debian-live-501-i386-gnome-desktop.iso,Type=fileio,IOMode=ro
        Alias LUN1
</code>

Now we add following line to "/etc/initiators.allow"
<code>  
ALL ALL
</code>
This should allow any initiator to access any lun device\\
and then, restart the target
<code>
sudo /etc/init.d/iscsitarget restart
</code>

===== Testing the target =====
The iscsi target is tested by installing iscsi initiator on same laptop.  Following is the procedure.\\

  * Installing
<code>
sudo apt-get install open-iscsi
</code>
  
  * configure iscsi initiator to start nodes automatically\\
Edit the file ''/etc/iscsi/iscsid.conf'' to have line ''node.startup = automatic''
  
  * and then restart the initiator
<code>
/etc/init.d/open-iscsi restart
</code>

  * Now, do the discovery of nodes available
<code>
$ sudo iscsiadm -m discovery -t st -p 192.168.0.1
192.168.0.1:3260,1 iqn.2001-04.com.example:storage.lun1
</code>
  * I dont know why this command is needed, but it was in the blog, so I am adding it here
<code>
$ sudo iscsiadm -m node
192.168.0.1:3260,1 iqn.2001-04.com.example:storage.lun1
</code>
  * Logging in
<code>
$ sudo iscsiadm -m node --targetname "iqn.2001-04.com.example:storage.lun1" --portal "192.168.0.1:3260" --login
Logging in to [iface: default, target: iqn.2001-04.com.example:storage.lun1, portal: 192.168.0.1,3260]
Login to [iface: default, target: iqn.2001-04.com.example:storage.lun1, portal: 192.168.0.1,3260]: successful
</code>

  * and it is done, you can see the new device with ''fdisk -l'' command
<code>
$ sudo fdisk -l
[sudo] password for pravin: 

Disk /dev/sda: 250.0 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0xa9f9aa9b

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1           5       40131   de  Dell Utility
[...]
[...]
[...]

Disk /dev/sdc: 724 MB, 724785152 bytes
23 heads, 61 sectors/track, 1008 cylinders
Units = cylinders of 1403 * 512 = 718336 bytes
Disk identifier: 0x00000000

Disk /dev/sdc doesn't contain a valid partition table

$ sudo mount -t iso9660 /dev/sdc mpoint
mount: block device /dev/sdc is write-protected, mounting read-only

$ mount
/dev/sda6 on / type ext3 (rw,relatime,errors=remount-ro)
[...]
[...]
[...]
/dev/sdc on /home/pravin/Etherboot/git/BKO.git/pxeknife/debian/debian-live-501-i386/mpoint type iso9660 (ro) 

$ ls mpoint
doc  isolinux  live  md5sum.txt
</code>

As Now I know that my target is working correctly, I am free to try out booting from this target 8-)

===== Configuring initramfs as initiator =====
I need to add all the tools, configuration files and kernel modules to initramfs so that I can use them from there to connect.

  * ** Step 1 **, __Kernel Modules__ on checking the contents of ''/etc/init.d/open-iscsi'' it seems that following kernel modules are to be inserted
<code>
modprobe iscsi_tcp
modprobe ib_iser 
</code>
  * These modules are already in debian initramfs, so no need to worry about that :)

  * ** Step 2 ** __Tools needed__ : Again ''/etc/init.d/open-iscsi'' tells us that it uses ''/sbin/iscsid'' and ''/sbin/iscsiadm''\\
but there are more iscsi related tools in /sbin
<code>
$ ls /sbin/iscsi*
/sbin/iscsiadm  /sbin/iscsid  /sbin/iscsi_discovery  /sbin/iscsi-iname  /sbin/iscsistart
</code>
To avoid any missing dependencies, better to add all above tools to initramfs.

  * ** Step 3 ** __Configuration Files__ : From man page of iscsiadm and iscsid, we can guess that following configuration files will be needed
<code>
/etc/iscsi/iscsid.conf
/etc/iscsi/initiatorname.iscsi
</code>
Trace: • bkodebianiscsi • dslbko • week10 • week12 • project_plan • transfer
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