On Fri, Mar 04, 2011 at 10:31:18AM +0200, Jussi Hirvi wrote:
Is there any (easy?) way to migrate running standalone CentOS 4 or 5 systems to xen virtual stacks?
Rebuilding those systems from scratch on the xen machine would take plenty of work.
If you're talking about Xen PV domUs, then the process is pretty much like this:
- ssh into the standalone system.
- make sure /etc/modprobe.conf includes xenblk driver (so that it'll be
included in the generated initrd when you install kernel-xen).
- fix /etc/fstab to have xvd* (xen virtual disk) devices instead of sd*.
- install kernel-xen rpm.
- verify kernel-xen is the default in /boot/grub/grub.conf.
- verify root= parameter is correct in /boot/grub/grub.conf for
kernel-xen.
- copy/transfer all the files from the standalone system to virtual
disk/image.
Make sure here to copy with preserving hardlinks, use tar or rsync -aH for this. And, you can exclude some content like /dev/* (but not the directory /dev itself!).
- create a configuration file for the new domU, make it use pygrub
bootloader, and make it use xvd* disks/devices.
Also, you may have to adjust network config.
- done.
And, if something goes wrong, you can simply loop mount the filesystem on the Xen host and fix things, maybe chrooting before depending on what you do.
Simon