11.04->11.10 KVM guest console problem

[James Crow]

On Thu, 08 Dec 2011 21:36:49 -0600, Serge Hallyn
<serge.hallyn at canonical.com> wrote:
> On 12/08/2011 11:17 AM, James Crow wrote:
>> Hi all,
>>
>> I am learning my way around with KVM. I have a Dell PowerEdge R410
server
>> that I installed 11.04 amd64 on. I then created two guests and
installed
>> 10.04.3 amd64 on each. Everything was working up to this point.
>>
>> Today, I decided to try the upgrade to 11.10 for the host OS. I did a
>> virsh save<guest-name>  <save-file>  for each guest and then upgraded
the
>> host OS.
>>
>> The upgrade seemed to progress without incident. I let the host restart
>> during the upgrade and once it was done I was able to SSH back in to
the
>> host.
>>
>> I should note that my home directory on the host is encrypted and I
have
>> setup SSH with keys so I can login to the host from my desktop without
>> entering a password. When I login this way my home directory on the
host
>> does not get mounted.
>>
>> After the upgrade I connected from my desktop with the GUI virtual
>> machine
>> manager and saw that both of my guests were running. Great!, I thought.
>> The
>> problem is I am now unable to connect to the console for either guest.
>> If I
>> try to open the console from the GUI app the window display "Connecting
>> to
>> graphical console for guest." I have waited over an hour and the
message
>> stays the same. I am also unable to connect to the guest from within
>> virsh
>> through a SSH session.
> 
> By 'console' do you mean the serial console, or vnc?  Are you able to 
> ssh into the guests?  Do they respond to a ping?
> 
>> libvirt appears to be working because I can run virsh from SSH and
>> connect
>> with the GUI manager. I am able to suspend/save/start the guest. I am
>> simply unable to view their consoles.
>>
>> Any ideas appreciated.
> 
> (Below is assuming that the VMs are not running right,  you can't ping 
> them.  If you can ping them, then likely libvirt is just not hooking up 
> the serial console right)
> 
> If I had to guess, I'd say that by saving and restoring - rather than 
> shutting down and later restarting - the guests, you ran into an 
> incompatibility in the save/restore image across qemu versions.  That's 
> just a guess, though.
> 
> So long as you still have the <save-file> for each guest, you could try 
> starting the guest up clean ('virsh start guest-name') and see if that 
> comes up fine.
> 
> Another thing you could try would be to create a 10.04 chroot (using 
> debootstrap) on your host, chroot into it, install qemu-kvm and libvirt,
> copy over the guest config files, and see if you can connect to the 
> consoles from there.
> 
> I'm tempted to ask for guest .xml files, but at that point we'd be 
> better off talking in a launchpad bug.
> 
> -serge

Serge,

Thanks for your response.

This morning I tried again with the gui Virtual Machine Manager and I was
able to connect to the console (I think the VMM software uses vnc) of one
of the guests. Yesterday I was able to ssh to and ping this guest so I knew
it was up. I was simply unable to view the graphical console.

I moved on to some other tasks and then came back and tried to reconnect.
This time when attempting to connect to the console (using the VMM gui) the
"Connecting to graphical console for guest" message simply stayed in place
of the console. After ~5 minutes of waiting I restarted libvirt-bin on the
host. After a libvirt-bin restart I was able to connect and view the
graphical console. After the first connection, I am unable to view the
console again until I restart libvirt-bin.

It is possible for me to view the graphical console. I just need to
restart libvirt every other time. There may be some sort of timeout that I
am not waiting for. I raise this as a possibility because I was able to
connect first thing this morning after letting the system idle overnight. I
think this may be a bug in libvirt-bin, but I am unsure of how to get the
information required for a good bug report.



Thank you,
James Crow

-- 
James Crow