Can't start newly created VM

[rbergerpa]

I used virt-manager to create a new VM and installed CentOS 5 into it. When running the installer in the VM, I used the default partitioning scheme. The install process completed OK, but I can't start the new vm with xm. I get the following error:

Using config file "./Dom3".
Traceback (most recent call last):
File "/usr/bin/pygrub", line 497, in ?
g = Grub(file, isconfig)
File "/usr/bin/pygrub", line 152, in __init__
self.read_config(file, isconfig)
File "/usr/bin/pygrub", line 331, in read_config
fs = fstype.open_fs(fn, offset)
File "/usr/lib/python/grub/fsys/ext2/__init__.py", line 35, in open_fs
return Ext2Fs(fn, offset = offset)
ValueError: offset argument not supported
No handlers could be found for logger "xend"
Error: Boot loader didn't return any data!

The xen config file created by virt-manager is

name = "Dom3"
memory = "500"
disk = [ 'tap:aio:/Dom3.img,xvda,w', ]
vif = [ 'mac=00:16:3e:32:0f:bf, bridge=xenbr0', ]
vfb = ["type=vnc,vncunused=1"]
uuid = "9ce08b9c-0c11-072f-5c66-1e0c409a82c8"
bootloader="/usr/bin/pygrub"
vcpus=1
on_reboot = 'restart'
on_crash = 'restart'

[mikemc]

I cannot start my newly created VM either. I'm attempting to install a paravirtualized RHEL 5 guest. The installation goes ok and I can see the new guest VM during the installation. However, as soon as the installation completes, the guest VM attempts to reboot and the window it is running in disappears. If I try to restore the VM using the Virtual Machine Manager, I get a popup message saying "Error restoring domain [the path to my image file]. Is the domain already running?"

[rbergerpa]

The problem seems to be related to this thread:

http://lists.xensource.com/archives/html/xen-users/2006-03/msg00948.html

Apparently pygrub can't access data in sub-partitions.

So while I know understand the cause (sort of...), I don't understand how to fix it. How do I boot a VM that was created with virt-manager?

[rbergerpa]

I found a workaround. I used lomount in Domain 0 to temporarily mount the guest domain's partitions, and copied the guest domain's kernel and ramdisk file to a directory in Domain 0. I then modified the config file for starting the guest domain to use these copies of the files.

i.e. replace

bootloader="/usr/bin/pygrub"

with

kernel = "/xenboot/vmlinuz-2.6.18-8.el5xen"
ramdisk = "/xenboot/initrd-2.6.18-8.el5xen.img"

This isn't too bad if all guest domains are running the same version of the same OS, but will get tedious if different domains are running differnt OS versions, or if a guest domain upgrades its installed kernel.


With all the hype about RHEL 5 having easy to use virtualization, it's annoying that this has been so tedious to get working.