So my new job uses Xen. Not the greatest, but it works.
I was testing Nova with KVM, but not using Nova.

I’m trying to see if I can get XenMotion working with DRBD and 2 nodes, no shared storage. But I need to be able to set it up on-the-fly. Ie, we don’t need to have XenMotion at all times. Only when something happens to a box that we need to move someone (a customer). So trying this at home first.

CentOS at work, but Ubuntu at home becuase Nova was so much easier to get up. CentOS people: See http://www.gitco.de/repo/

First. Get Xen 4.1 and make packages. Thankfully someone has the hard work done for this:
<a href=http://virtualusr.wordpress.com/2011/01/20/xen-4-x-testing-unstable-ubuntu/>VirtualUsr - Xen 4.x on Ubuntu</a>

so run the stuff there, and run this command:
debian/bin/packageXen4x.sh

That’ll get 4.1.X (in this case 4.1.2rc3).

The Ubuntu kernel shipped with 11.04 works out of the box. – I thought this was true, but it’s not.
You still need to build a kernel, or use a Debian one. Right now my remote boxes are messed up so I will fix them later.

Install the package files with dpkg -i ..generated-packages…
edit /etc/modules and add in:
xen-evtchn
to the file and reboot into Xen 4.1.
One of the packages doesn’t quite install right unless you’re in xen, so log in to your box (you might have to do this via ssh) and run:
root@box#: apt-get -f install

Which will fix things up.

Do yourself a favor and don’t kill xenconsole - it’ll halt your box. Lesson learned.

I created a CentOS 6 VM using the instructions here: CentOS 6 domU installation

I modified the kickstart to more closely match our current setup. The one on that site uses LVM on top of the real backing store, which is redundant for us.
After installation, DRBD needs to be set up next.