Getting High With Lenny

Getting High With Lenny

The aim here is to set up some high available services on Debian Lenny (at the time of writing still due to be released). Most of the documentation available for such a setup I found on the net are based on Xen but I prefer to use Vserver for the "virtualisation" because of its configurability, shared memory and cpu resources and basically the raw speed. DRBD8 and Heartbeat should take care of the availability magic in case a machine shuts down unexpectedly.

*2 machines
*both machines have 1 single large DRBD partition.
*primary/seconday there is always 1 machine active and 1 on standby.
*1 LVM partition per Vserver on top of the DRBD partition, for quota support from within the guest and LVM snapshots.
*the Vservers /etc/vserver and /var/lib/vservers directories will be placed on the DRBD partition mounted on /VSERVERS.

The partitioning looks as follows in this example.

      c0d0p1             Boot              Primary         Linux ext3                                        10001.95
      c0d0p5                               Logical         Linux swap / Solaris                               1003.49
      c0d0p6                               Logical         Linux

For this setup we go for 1 single DRBD partition, node1 is primary and node2 secondary.

Trying to not to confuse ourselves we follow the naming scheme below. (for an almost setup (not tested) with 2 drbd disks, 1 primary on each node [[ha-hosting-setup-vserver-double-drbd]])

machine1 will use the following names:
* hostname = node1
* IP number = 192.168.1.100
* is primary for r0 on disk c0d0p6
* physical volume on r0 is /dev/drbd0
* volume group on /dev/drbd0 is called drbdvg0

machine2 will use the following names:
* hostname = node2
* IP number = 192.168.1.200
* is secondary for r0 on disk c0d0p6
* physical volume on r0 is /dev/drbd0
* volume group on /dev/drbd0 is called drbdvg0

 

Install the Vserver packages

Be sure to choose the amd64 version in case you are running 64 bit, in my case I'm running 32bit with more than 4GB RAM.

apt-get install linux-image-2.6-vserver-686-bigmem util-vserver vserver-debiantools

As usual a reboot is needed to boot this kernel.

With Etch i found that the Vserver kernel often ended up as second in the grub list, not so in Lenny but to be safe check the kernel stanza in /boot/grub/menu.lst before you reboot, especially when doing this from a remote location.