This is an old revision of the document!


Ubuntu 9.04 (jaunty jackalope)

(this howto is based on the Debian Etch iSCSI howto with some major changes)

Introduction

This howto shows how to make an existing installation of a recent *buntu (ubuntu, kubuntu, edubuntu, xubuntu and so on) bootable over the network using iSCSI. If you are experienced with ubuntu and initramfs / initrd creation you can install ubuntu directly onto the iscsi target using the desktop (i386 or amd64) install CD (more on that later). The alternate install disk is not capable of installing additional packages at runtime, because of the limitations of the busybox environment.

If you have the possibility it is more comfortable to install ubuntu onto a local HDD, USB stick or whatever and boot into the installed system after that.

Assumptions

This howto is based on the following assumptions:

  • An installation of ubuntu or one of its pendants in the latest (jaunty) version
  • the system is installed on a single harddrive, no matter how much partitions you have set up
  • there is an already done iscsi target on an iscsi server
  • there is a working dhcp server (although you will only need it for comfort, configuring gpxe manually does also work)

Preparing the initrd

The debian howto recommended to compile open-iscsi yourself as iscsistart and fwparam_ibft were not available in the debian packages that time. This is not necessary for ubuntu for some reasons:

  • fwparam_ibft is no longer a (fully featured) component of neither the open-iscsi semi-stable release (which does not even support kernel 2.6.28+) nor the development git source tree FIXME Is there some kind of a replacement?
  • iscsistart is available via open-iscsi from the ubuntu repositories.
  • the initramfs scripts are even prepared for iscsi usage in some way

But the initramfs / initrd has to be recreated to include the required iscsi stuff: (I use joe for some vintage reason, but you are of course free to use the editor of your choice)

install required packages

 sudo aptitude install initramfs-tools open-iscsi sysv-rc-conf

change the initiatorname (of the client) to something unique if you are planning to set up many boxes

 sudo echo "InitiatorName=iqn.1993-08.org.debian:01:22b2ed5d3ccc" > /etc/iscsi/initiatorname.iscsi

touch the indicatorfile, which is queried to determine, whether the daemons are to be copied into the new initrd

 sudo touch /etc/iscsi/iscsi.initramfs

now we have to workaround a bug in the jaunty stable tree, so edit /usr/share/initramfs-tools/hooks/iscsi with your favourite editor:

 sudo joe /usr/share/initramfs-tools/hooks/iscsi
 and change line 25 from:
    copy_exec /usr/sbin/iscsistart /sbin
 to
    copy_exec /sbin/iscsistart /sbin

Even if the modules for the network cards are loaded early enough, udev still initializes too late to activate the NICs which will cause the iscsi script to fail. As long as there is not a much smarter solution, you will be fine to copy the udev script from /scripts/nfs-top to /scripts/local-top/early_udev FIXME Perhaps it is smarter to copy it to /etc/initramfs-tools/scripts/local-top/

 sudo cp /usr/share/initramfs-tools/scripts/nfs-top/udev /usr/share/initramfs-tools/scripts/local-top/early_udev
 ls -lha /usr/share/initramfs-tools/scripts/local-top/
 insgesamt 12K
 drwxr-xr-x  2 root root   35 2009-04-28 23:12 .
 drwxr-xr-x 10 root root 4,0K 2009-04-28 22:59 ..
 -rwxr-xr-x  1 root root  430 2009-04-28 23:00 early_udev
 -rwxr-xr-x  1 root root 1,9K 2009-04-28 22:32 iscsi

generate the new initrd('s)

 sudo update-initramfs -u
 update-initramfs: Generating /boot/initrd.img-2.6.28-11-generic

Preparing the system

now we have to take care that neither /etc/init.d/networking nor the Network Manager reconfigures the interface again during the init process or X11 startup so edit /etc/network/interfaces:

 sudo joe /etc/network/interfaces
 and change the appropiate entry for your primary NIC from:
    auto eth0
    #iface eth0 inet dhcp
 to
    auto eth0
    iface eth0 inet manual

As we do not have fwparam_ibft we cannot read out the ibft contents that gpxe has left, so we have to specify vital iSCSI information via Kernel command line options. Use your favourite boot manager for this. I did use grub, because it is preinstalled and my no. 1 choice anyway, but it is most likely possible to use gpxe or a gpxe-script to pass these parameters. (FIXME edit this if you have more detailed knowledge on this - as gpxe scripting is still on my to-do-list) Make the boot process verbose if you want to be able to see potential problems immediately when they occur.

This are the available options (which are parsed from /proc/cmdline):

  • ISCSI_INITIATOR
  • ISCSI_TARGET_NAME
  • ISCSI_TARGET_IP
  • ISCSI_TARGET_PORT
  • ISCSI_TARGET_GROUP
  • ISCSI_USERNAME
  • ISCSI_PASSWORD
  • ISCSI_IN_USERNAME
  • ISCSI_IN_PASSWORD

It could look like this:

 title		Ubuntu 9.04, kernel 2.6.28-11-generic iSCSI
 uuid		f859db1e-39f8-4539-9f0e-8292f8f93cca
 kernel		/vmlinuz-2.6.28-11-generic ISCSI_INITIATOR=iqn.2009-04.arbeitsgruppe:general ISCSI_TARGET_NAME=iqn.2009-04.Arbeitsgruppe.Commander1024:general.ubuntu ISCSI_TARGET_IP=192.168.234.1 ISCSI_TARGET_PORT=3260 root=UUID=021ebcfc-188a-41ba-9864-ee18cbf7af9f ro
 initrd		/initrd.img-2.6.28-11-generic
 quiet

Transfer your image to the iSCSI Target server

Installing ubuntu directly onto the iSCSI SAN

DELETEME WIP

Installing ubuntu directly onto SAN is basically the same as the method: HDD → SAN and takes advantage of the possibility to install packages in the running live cd system. But that means you cannont use the Alternate install disc out-of-the-box.

Boot your favourite *buntu variant using the desktop CD. Install the open-iscsi packate in the live system

 sudo aptitude install open-iscsi
 sudo iscsi_discovery <SAN-IP>
    Set target iqn.2009-04.apobyte.fattony:eee-box.ubuntu to automatic login over tcp to portal 192.168.111.212:3260
    Logging out of session [sid: 3, target: iqn.2009-04.apobyte.fattony:eee-box.ubuntu, portal: 192.168.111.212,3260]
    Logout of [sid: 3, target: iqn.2009-04.apobyte.fattony:eee-box.ubuntu, portal: 192.168.111.212,3260]: successful
    discovered 1 targets at 192.168.111.212
 sudo iscsiadm -m node -p <SAN-IP> -T iqn.2009-04.apobyte.fattony:eee-box.ubuntu -l

Now you should be logged into your SAN Target (if it does not require Authentication, this could be done now by editing the config file

 sudo joe /etc/iscsi/nodes/iqn.2009-04.apobyte.fattony\:eee-box.ubuntu/192.168.111.212\,3260\,1/default

and add the following to the config file:

  node.session.auth.username = <username>
  node.session.auth.password = <password>

now the login command will finally work which can be veriefied with the “dmesg” program. This will give you a hint, which disk you will have to partition and install ubuntu to:

 [   62.491211] scsi8 : iSCSI Initiator over TCP/IP
 [   63.540037] scsi 8:0:0:0: Direct-Access     IET      VIRTUAL-DISK     0    PQ: 0 ANSI: 4
 [   63.541815] sd 8:0:0:0: [sdg] 50331648 512-byte hardware sectors: (25.7 GB/24.0 GiB)
 [   63.548975] sd 8:0:0:0: [sdg] Write Protect is off
 [   63.548979] sd 8:0:0:0: [sdg] Mode Sense: 77 00 00 08
 [   63.550486] sd 8:0:0:0: [sdg] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
 [   63.556047] sd 8:0:0:0: [sdg] 50331648 512-byte hardware sectors: (25.7 GB/24.0 GiB)
 [   63.560353] sd 8:0:0:0: [sdg] Write Protect is off
 [   63.560357] sd 8:0:0:0: [sdg] Mode Sense: 77 00 00 08
 [   63.565124] sd 8:0:0:0: [sdg] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA

Now start the install program and install ubuntu exactly the same way you would do on a local harddrive. There is no difference at all, even grub goes onto this drive by default so nothing to take care about, except the fact you should not reboot your box right after the installation procedure.

Now mount your newly created root device (that partition you mount as “/”), if you are unsure you can use “fdisk -l /dev/sdX” to call your partition structure back to mind and create a sane environmet so that all the scripts you will use will be satisfied. I alway use a separate /boot partition, so we have to keep that in mind.

 sudo mkdir /mnt/sdc3
 sudo mount /dev/sdc3 /mnt/sdc3
 mount /dev/sdc1 /mnt/sdc3/boot/
 sudo chroot /mnt/sdc3
 sudo su -
 mount -t proc none /proc
 hostname -F /etc/hostname

Now jump back to “Preparing the initrd” and walk down the howto from there on.

Troubleshooting

Emergency Busybox Shell on Boot

The following procedure will allow you to get your system up with 2 short commands, if something went wrong and you are dropped to a Busybox Shell:

 /scripts/local-top/iscsi (This will work now out-of-the-box as the networking modules are loaded now)
 exec switch-root (to continue the boot process)

Crash on Shutdown

If ubuntu keeps crashing on system shutdown, try to disable networking and openiscsi scripts for shutdown, because shutting down the network will cause loss of the root-device:

 sudo sysv-rc-conf
 before:
 ┌ SysV Runlevel Config   -: stop service  =/+: start service  h: help  q: quit ┐
 │                                                                              │
 │ service      1       2       3       4       5       0       6       S       │
 │ ---------------------------------------------------------------------------- │
 │ networking  [ ]     [ ]     [ ]     [ ]     [ ]     [X]     [X]     [X]      │
 │ open-iscsi  [X]     [ ]     [ ]     [ ]     [ ]     [X]     [X]     [X]      │
 └──────────────────────────────────────────────────────────────────────────────┘
 ┌──────────────────────────────────────────────────────────────────────────────┐
 │ Use the arrow keys or mouse to move around.      ^n: next pg     ^p: prev pg │
 │                        space: toggle service on / off                        │
 └──────────────────────────────────────────────────────────────────────────────┘
 
 after:
 ┌ SysV Runlevel Config   -: stop service  =/+: start service  h: help  q: quit ┐
 │                                                                              │
 │ service      1       2       3       4       5       0       6       S       │
 │ ---------------------------------------------------------------------------- │
 │ networking  [ ]     [ ]     [ ]     [ ]     [ ]     [ ]     [ ]     [ ]      │
 │ open-iscsi  [X]     [ ]     [ ]     [ ]     [ ]     [ ]     [ ]     [ ]      │
 └──────────────────────────────────────────────────────────────────────────────┘
 ┌──────────────────────────────────────────────────────────────────────────────┐
 │ Use the arrow keys or mouse to move around.      ^n: next pg     ^p: prev pg │
 │                        space: toggle service on / off                        │
 └──────────────────────────────────────────────────────────────────────────────┘

FIXME: Notes from contributors


QR Code
QR Code sanboot:ubuntu_iscsi (generated for current page)