Proxmox ISCSI installation

What is iSCSI?

iSCSI is a protocol who can travel SCSI's commands over the network. The main advantage is that you don't need any harddrives for getting a fully functional server. This can be also realized by using a real FiberChannel SAN but it's a lot more expensive. A diskless server will boot over the network, asking its disk image to the SAN. Today, a lot of system supports iSCSI but they don't really support iSCSI install and boot (only VMWare supports that). However, you can making this works on some Linux's system by making some tricks and that's what we will see .

What do you need?

You need a functionnal iSCSI target (OpenFiler can be a good solution) and your diskless server must support iSCSI boot (if not, you can use iPXE for that). You also need a DHCP server for network booting. You can find some tutorials about iPXE (formely gPXE) on the gPXE wiki : http://etherboot.org/wiki/start

Here we go !

1 - Install a clean Debian on a physical machine or into a VM. Using a VM is not a problem because we only need this for formating and installing another Debian on the iSCSI target.

2 - Install open-iscsi

aptitude install open-iscsi

This util manages to attach an iSCSI target to the session.

3 - Attach the iSCSI target

iscsiadm --mode node --targetname <IQN> -p <IP> --login

You should now see your iSCSI target into /dev/sdX.
Example :

iscsiadm --mode node --targetname iqn.2006-01.openfiler.com:tsn.dcb5e30d5a -p 188.102.200.254 --login

4 - Create all partitions you need for your future Debian installation (you can use gpart for exemple).

NOTE : The first partition must begin at the 2048 sector !!! If don't, you will not be able to install Grub on the iSCSI target !

5 - Create a dir into /mnt (for example /mnt/debian) for preparing mouting.

6 - Mount the iSCSI target's main partition on this dir

mount /dev/sdX1 /mnt/debian

7 - Install debootstrap

aptitude install debootstrap

This utils manages to install a light debian install by using deb packages to a target.

8 - Install a debian squeeze to /mnt/debian by using debootstrap

debootstrap squeeze /mnt/debian http://ftp.us.debian.org/debian

You can also install another debian like lenny, but squeeze supports iSCSI better (you need to do more tricks on Lenny for having a functional iscsi boot). This can take some time (depending on your connection).

You should now have a right lightweight Squeeze install on the main partition

9 - Mount this system's dirs, it is necessary for preparing the new squeeze installation for iscsi booting.

mount -o bind /dev /mnt/debian/dev
mount -o bind /sys /mnt/debian/sys
mount -o bind /proc /mnt/debian/proc

10 - Use now this Debian by using chroot (who can change the root dir by another dir).

chroot /mnt/debian

You are now logged on your new system

11 - Install Grub

aptitude install grub

It should install Grub into the MBR of your iSCSI target. If not, you can use grub-install /dev/sdX.

12 - Add the Proxmox repository and update

echo "deb http://download.proxmox.com/debian lenny pve" >> /etc/apt/sources.list
wget -O- "http://download.proxmox.com/debian/key.asc" | apt-key add -
aptitude update

13 - Add the loopback interface (if don't, you will not be able to use nfs-common who is needed by the pve-manager). For this :

nano /etc/network/interfaces

Add this to the file :

auto lo
iface lo inet loopback

14 - Install the proxmox 2.6.32-4 kernel and headers (the 2.6.35 seems to not work with iscsi booting)

aptitude install pve-kernel-2.6.32-4-pve pve-headers-2.6.32-4-pve

This action should update grub automatically.

15 - Install open-iscsi for making this installation fully supports iSCSI

aptitude install open-iscsi

16 - Precise to open-iscsi to manage iBFT informations (iBFT are informations made by iSCSI boot firmware like iPXE for the system)

echo "ISCSI_AUTO=true" > /etc/iscsi/iscsi.initramfs

By using this, you don't have to precise the iSCSI IQN and the iSCSI Target's IP to the system, only iscsi boot firmware need this.

17 - Install initramfs-tools and update initramfs

aptitude install initramfs-tools
update-initramfs -u

18 - Create a root password

passwd

Your new Debian system should now boot over iSCSI ! Once booted you can install proxmox by simply using :

aptitude install proxmox-ve-2.6.32 ntp ssh lvm2