Red Hat Bugzilla – Bug 246169
Cannot start xen domains after FC6->F7 upgrade, using fc6 xen kernel: 2.6.20-1.2952-1.fc6xen
Last modified: 2007-11-30 17:12:08 EST
Description of problem:
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. upgrade FC6->F7
2. boot F7 using 2.6.20-1.2952.fc6xen kernel
3. xm create /etc/xen/xen0 -c
4. see error
Error: Unable to connect to xend. No such file or directory. Is xend running?
And we make sure that xend is running - still errors.
no error - xen domain starts
We are booting the 2.6.20-1.2952.fc6xen kernel because the F7 xen kernel crashes
on our hardware. see bug# 245627
Found this in the xen-debug.log:
Xend started at Thu Jun 28 14:49:56 2007.
domctl operation failed -- need to rebuild the user-space tool set?
sysctl operation failed -- need to rebuild the user-space tool set?
Exception starting xend: (13, 'Permission denied')
Exception in thread Thread-2:
Traceback (most recent call last):
File "/usr/lib/python2.5/threading.py", line 460, in __bootstrap
File "/usr/lib/python2.5/site-packages/xen/xend/XendMonitor.py", line 220, in run
for domid, cputimes in self._get_cpu_stats().items():
File "/usr/lib/python2.5/site-packages/xen/xend/XendMonitor.py", line 198, in
for domain in self.xc.domain_getinfo():
Error: (13, 'Permission denied')
I've never seen these errors before under fc6.
You can't use a FC6 Xen kernel with F7 Xen userspace & vica-verca. They must be
matched. Either all FC6 based, or all F7 based. This is because Xen 3.0.3 in FC6
is *not* ABI compatible with Xen 3.1.0 in F7.
Either run all FC6, or all F7 - you can't mix & match at will.
Which F7 packages do I need to replace to get this working?
At the very least the 'kernel-xen' and 'xen' RPMs must be matched. This may
affect dependancies - you'll have to resolve any issues that arise in that
Is it possible to run xen 3.1.0 with the fc6 kernel by loading some kernel module?
This is not going to be doable. Xen package has a list of dependencies as long
as your arm.
So how did F7 use a 2.6.20 xen kernel (2925) that worked with xen 3.1.0?
Can F7 be upgraded to use a newer 2.6.20 kernel (at least 2952) that would work
with xen 3.1.0? This would temporarily solve our problem.
The 2.6.20 kernel would have to use the old IDE drivers in our case and not the
new libata drivers.
It is quite simple - either use all FC6 RPMs, or use F7 RPMs. If you try to mix
& match RPMs between 2 distros you are own your own & we can't help.
Much as we'd like Xen to be compatible between FC6 & F7, the upstream Xen
utterly fails to provide a stable ABI between userspace & hypervisor, so it
simply won't work.