[ovirt-users] VM get stuck randomly

[Nir Soffer]

On Sun, Mar 13, 2016 at 9:46 AM, Christophe TREFOIS
<christophe.trefois at uni.lu> wrote:
> Dear all,
>
> I have a problem since couple of weeks, where randomly 1 VM (not always the same) becomes completely unresponsive.
> We find this out because our Icinga server complains that host is down.
>
> Upon inspection, we find we can’t open a console to the VM, nor can we login.
>
> In oVirt engine, the VM looks like “up”. The only weird thing is that RAM usage shows 0% and CPU usage shows 100% or 75% depending on number of cores.
> The only way to recover is to force shutdown the VM via 2-times shutdown from the engine.
>
> Could you please help me to start debugging this?
> I can provide any logs, but I’m not sure which ones, because I couldn’t see anything with ERROR in the vdsm logs on the host.

I would inspect this vm on the host when it happens.

What is vdsm cpu usage? what is the qemu process (for this vm) cpu usage?

strace output of this qemu process (all threads) or a core dump can help qemu
developers to understand this issue.

>
> The host is running
>
> OS Version:             RHEL - 7 - 1.1503.el7.centos.2.8
> Kernel Version: 3.10.0 - 229.14.1.el7.x86_64
> KVM Version:            2.1.2 - 23.el7_1.8.1
> LIBVIRT Version:        libvirt-1.2.8-16.el7_1.4
> VDSM Version:   vdsm-4.16.26-0.el7.centos
> SPICE Version:  0.12.4 - 9.el7_1.3
> GlusterFS Version:      glusterfs-3.7.5-1.el7

You are running old versions, missing lot of fixes. Nothing specific
to your problem
but this lower the chance to get a working system.

It would be nice if you can upgrade to ovirt-3.6 and report if it made
any change.
Or at lest latest ovirt-3.5.

> We use a locally exported gluster as storage domain (eg, storage is on the same machine exposed via gluster). No replica.
> We run around 50 VMs on that host.

Why use gluster for this? Do you plan to add more gluster servers in the future?

Nir