Xen and Fedora

Submitted by TomMD on Wed, 03/19/2008 - 7:36pm.

So this is a little off topic for sequence.complete.org, but I'm going to document some of my run-ins with Xen and Fedora here. Also, I am looking for somewhere more generic to move my blog - any suggestions? EDIT: I just decided to go with wordpress, so you can find my ramblings at tommd.wordpress.com

Installing Xen
I had some issues with installing/using Xen from source. I mudded the waters at the start by trying out various versions / packagings (Fedora Xen package, xen-3.0.4-testing, xen-3.2-testing, xen-3.2.0) and I discovered that:

  1. 'make clean' will remove ALL xen kernels (rm /boot/*xen*). This eliminated a perfecting fine xen-3.0.4 install when I was screwing around with 3.2-testing.
  2. 'make clean' missed some python scripts - causing the xm tool funky behavior till I manually cleaned /usr/lib and reinstalled Xen.
  3. Fedoras Xen package is fine (currently a Xen-3.1 derivative) , unless you have special desires like ACM - in which case you certainly need to use a source distribution. Good work Fedora!

Installing Fedora PVMs
Using the virt-install tool (package: python-virtinst) it is dead simple to install stable Fedora distros (of coarse the GUI tool, virt-manager, exists too):

# virt-install -n F8 -r 512 --vcpus=1 -f /var/lib/xen/images/F8.img \
--vnc -p -b virbr0 -l "http://mirrors.kernel.org/fedora/releases/8/Fedora/i386/os/"

But be sure to enable packet forwarding by adding to your /etc/sysctl.conf. If you don't, you'll find the packets won't get forwarded from your bridge (xenbr0 or virbr0) to your network.

# Controls IP packet forwarding
net.ipv4.ip_forward = 1

Or use sysctl or directly alter /proc/sys/net/ipv4/ip_forwarding, if you are rustic like me.

Dealing with Rawhide
I figured I could be a rawhide tester by running it as a DomU - I was right and wrong.

  1. Rawhide can not act as Dom0. It seem that, due to the PV_Ops task, Fedora 9 is not intended as Dom0 - Fedora 8 and 10 will fill the host role.
  2. Rawhide doesn't currently run as a paravirtual machine (PVM - a type of DomU). I've reported bug 437217, which has an obvious fix, and bug 437706, which is where I'm at now.