nova-compute fails to start with existing VMs with a "cdrom"

[Brian J. Murrell]

I have some pre-existing VMs on my (test) compute node. One of them has a CD-ROM device configured:

    <disk type='file' device='cdrom'>
      <driver name='qemu' type='raw'/>
      <target dev='hdc' bus='ide'/>
      <readonly/>
      <alias name='ide0-1-0'/>
      <address type='drive' controller='0' bus='1' target='0' unit='0'/>
    </disk>

This causes LibvirtDriver.get_instance_disk_info() to fail out because path_node.get('file') for that "disk" returns None. I put a:

            if not path:
                LOG.debug(_('skipping disks with no %(path)s') %
                          locals())
                continue

after the:

            if disk_type != 'file':
                LOG.debug(_('skipping %(path)s since it looks like volume') %
                          locals())
                continue

in get_instance_disk_info() get past the issue.

[Russell Bryant (russellb)]

I think running vms via libvirt outside of nova on a compute node is outside the scope of normal and expected usage, so I think the priority should be brought down from High.

[Brian J. Murrell (brian-interlinx)]

On 13-03-05 02:56 PM, Russell Bryant wrote:
> I think running vms via libvirt outside of nova on a compute node is
> outside the scope of normal and expected usage, so I think the priority
> should be brought down from High.

The point, really, isn't that this was a VM configured outside of nova
so much as it was a valid configuration that nova simply failed to handle.

[Michael Still (mikal)]

When I triaged this my rationale was that having your VM break because of valid libvirt config is unexpected and therefore a big deal. I can see an argument that says that config is always managed by nova and therefore this is self inflicted, but I still think breaking is kind of a big deal.

However, if the consensus is to triage this lower I can live with that.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/24658

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/24658
Committed: http://github.com/openstack/nova/commit/cb369dab7184e72f24e70554828a7c4ca754d268
Submitter: Jenkins
Branch: master

commit cb369dab7184e72f24e70554828a7c4ca754d268
Author: Davanum Srinivas <email address hidden>
Date: Mon Mar 18 13:51:50 2013 -0400

    libvirt: Tolerate existing vm(s) with cdrom(s)

    When there is an existing vm with cdrom (not started by Nova), we
    should tolerate missing file attribute (just skip those)

    Fixes LP# 1144756

    Change-Id: I43d45872e2d7348801b2e54cd43651609676f372

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/folsom
Review: https://review.openstack.org/27803

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/27803
Committed: http://github.com/openstack/nova/commit/8068a1d18249f5b871e2df3b27b2fb7141d1cc57
Submitter: Jenkins
Branch: stable/folsom

commit 8068a1d18249f5b871e2df3b27b2fb7141d1cc57
Author: Davanum Srinivas <email address hidden>
Date: Mon Mar 18 13:51:50 2013 -0400

    libvirt: Tolerate existing vm(s) with cdrom(s)

    When there is an existing vm with cdrom (not started by Nova), we
    should tolerate missing file attribute (just skip those)

    Fixes LP# 1144756

    Change-Id: I43d45872e2d7348801b2e54cd43651609676f372
    (cherry picked from commit cb369dab7184e72f24e70554828a7c4ca754d268)