CentOS 5.6 GitCO xen 3.4.3 kernel, libvirt-client and xen-libs update issues

A recent CentOS 5.5 to 5.6 update has caused one of my xen servers to stop functioning... This has happened few times in the past... and I keep forgetting to look before I reboot. Maybe documenting it here will help me remember and help others QUICKLY get past the xend failing to start with the error of:

[2011-04-16 15:34:19 5082] INFO (SrvDaemon:336) Xend changeset: unavailable.
[2011-04-16 15:34:19 5082] ERROR (SrvDaemon:349) Exception starting xend ((13, 'Permission denied'))
Traceback (most recent call last):
File "/usr/lib64/python2.4/site-packages/xen/xend/server/SrvDaemon.py", line 341, in run
servers = SrvServer.create()
File "/usr/lib64/python2.4/site-packages/xen/xend/server/SrvServer.py", line 251, in create
root.putChild('xend', SrvRoot())
File "/usr/lib64/python2.4/site-packages/xen/xend/server/SrvRoot.py", line 40, in __init__
self.get(name)
File "/usr/lib64/python2.4/site-packages/xen/web/SrvDir.py", line 84, in get
val = val.getobj()
File "/usr/lib64/python2.4/site-packages/xen/web/SrvDir.py", line 52, in getobj
self.obj = klassobj()
File "/usr/lib64/python2.4/site-packages/xen/xend/server/SrvNode.py", line 30, in __init__

Here is the deal. We have been using the Xen 3.4.3 repo from Gitco. For some reason yum will not keep the "kernel" line that matches up with the xen install from xen-3.4.3. So, the VERY simple fix (till the next kernel update) is just to make sure that your grub.conf has a line of "kernel /xen.gz-3.4.3" and not whatever gets dumped there by yum. Hope this helps people with this error.

The second issue with the (finally) released CentOS 5.6 update related to using the xen 3.4.3 from GitCO is the inclusion of the libvirt-client-0.7.0-6.el5. This is now an older version with the 5.6 update now out. The error you see from try a yum update is:

Transaction Check Error:
file /usr/bin/virsh from install of libvirt-0.8.2-15.el5.3.x86_64 conflicts with file from package libvirt-client-0.7.0-6.el5.x86_64
file /usr/bin/virt-xml-validate from install of libvirt-0.8.2-15.el5.3.x86_64 conflicts with file from package libvirt-client-0.7.0-6.el5.x86_64
file /usr/lib64/libvirt.so.0 from install of libvirt-0.8.2-15.el5.3.x86_64 conflicts with file from package libvirt-client-0.7.0-6.el5.x86_64
file /usr/share/libvirt/schemas/capability.rng from install of libvirt-0.8.2-15.el5.3.x86_64 conflicts with file from package libvirt-client-0.7.0-6.el5.x86_64

The fix is:

rpm -e --nodeps libvirt-client
yum update

If you accidentally got the old i386 xen-libs, just run:

rpm -e xen-libs.i386
yum update