Work in progress. -- Thom 17/12/09
Creating new Xen instances
Naming your host
- Think of a name. We like Dr Who themed names! If you recycle a name you'll probably upset Thom -- why not ask Malcolm for advice?
- At this point you should also create a wiki page explaining your VMs purpose and config. Use one of the other Xen machine's pages as a starting point.
- Find a free IP and add forward and reverse mappings to the DNS.
Find a Xen host
- Our main constraints on Xen hosts are RAM and disk space.
- Use vgs to show free disk space in the volume group
- Check amount of RAM allocated to dom0 in xentop for a poor estimation of potentially free RAM.
Create disk volumes
- Create root volume: lvcreate -l 4GB -n <hostname>-root <volume-group>
- 2GB is just about enough for a Debian install.
- You can find out the volume group name with vgs
- Create swap volume: lvcreate -l 256MB -n <hostname>-swap <volume-group>
- Use your favourite rule of thumb for guessing a completely arbitrary quantity of swap space to allocate. If your machine starts thrashing you'll probably upset someone, so it's better off being small.
- Create root filesystem: mke2fs -j /dev/<volume-group>/<hostname>-root
- Create swap filesystem: mkswap /dev/<volume-group>/<hostname>-swap
Create Xen configuration file
Run Debian installer
Booting your instance
xm create -c <newmachinename>.conf
to get the instance up and running. You should be able to log in. Use ctrl+] to get back to the Xen host console.
Booting and Shutting Down
Xen's init scripts are set up to perform an `xm save` (copy the RAM to disk) for each domU that's running when vislor and/or adric are shut down and to restore saved domUs on boot. This should take care of the cases where tardis is shut down intentionally, but a bit more work will have to be done following an unexpected power loss. (When do they happen anyway? ;-)
To start all domUs on vislor do:
for foo in /etc/xen/*.conf; do xm create -c $foo; done <WAIT FOR A LOGIN PROMPT> ctrl+] <WAIT FOR A LOGIN PROMPT> ctrl+] ....