Tips and Tricks for Using Xen under Ubuntu or Debian

I’ve been reading through the launchpad bugs for Xen and thought that I could use them to illustrate some tips and tricks for using Xen in Ubuntu or Debian. I ran into some problems with Xen today on a system after having been upgraded from Ubuntu 7.10 to Ubuntu 8.04 and from Xen 3.1 to Xen 3.2. This should help as a checklist when diagnosing various Xen problems.

Tips

• Always turn off tx-checksumming in each DomU
  • bug 154271
  • See also: Virtualization Tip: Always disable checksumming on virtual ethernet devices
• Always set a static mac address for each DomU
  • bug 150805
• Never use Network Manager on a Dom0 (or probably a DomU)
  • bug 150805
• Make sure to install package python-xml on the Dom0
  • bug 174048
• Make sure to run the latest kernels in each Ubuntu 8.04 DomU for networking to work
  • bug 218126
• Be very careful when removing xen-utils-3.1 following an upgrade to xen-utils-3.2
  • bug 236262
• Use “tap:aio” instead of “file” to access a file backed DomU.
  • bug 199533, bug 205450
• Take steps to ensure a functional console
  • There are several ways to do this.
  • bug 205450, bug 144631, bug 139046
• Make sure to remove /etc/rcS.d/S08hwclockfirst.sh and /etc/rcS.d/S11hwclock.sh unless using a separate wall clock and especially on i386 architectures
  • you can run: update-rc.d hwclock remove; update-rc.d hwclockfirst remove
  • bug 163605, bug 144631
• Make sure you know the locations of pygrub, hvmloader, and qemu-dm
  • See below for locations for Ubuntu 7.10 and 8.04
  • bug 132256, bug 132135
• On the i386 architecture make sure to install libc6-xen on every Dom0 and DomU
• Make sure to do a full test of memory with memtest (which should be a given for any computer)

Files

• pygrub: /usr/bin/pygrub
• hvmloader
  • gutsy: /usr/lib/xen-ioemu-3.1/boot/hvmloader
  • hardy: /usr/lib/xen/boot/hvmloader
• qemu-dm
  • gutsy: /usr/lib/xen-ioemu-3.1/bin/qemu-dm
  • hardy: /usr/lib/xen/bin/qemu-dm