[nova][qa][infra] Adding no_timer_check to the kernel command line of our CI images

Lee Yarwood lyarwood at redhat.com
Thu Aug 19 09:02:27 UTC 2021


On 19-08-21 09:07:39, Radosław Piliszek wrote:
> On Wed, Aug 18, 2021 at 11:45 PM Clark Boylan <cboylan at sapwetik.org> wrote:
> >
> > On Wed, Aug 18, 2021, at 2:07 PM, Lee Yarwood wrote:
> > > Hello all,
> > >
> > > For a while now we've been attempting to track down some infrequent but
> > > annoying Tempest test cleanup failures in CI when detaching volumes from
> > > an instance. Finally after rewriting part of the Tempest logic
> > > controlling the cleanup we've been able to confirm that this is being
> > > caused by a kernel panic within the instance at boot time as documented
> > > in the following bug:
> > >
> > > Failure to detach volume during Tempest test cleanup due to APIC related
> > > kernel panic within the guest OS
> > > https://bugs.launchpad.net/nova/+bug/1939108
> > >
> > > This had been previously found in 2014 but at the time a fix was only
> > > proposed to Nova that would solve this when using a supplied kernel
> > > image:
> > >
> > > cirros 0.3.1 fails to boot
> > > https://bugs.launchpad.net/cirros/+bug/1312199
> > >
> > > Use no_timer_check with soft-qemu
> > > https://review.opendev.org/c/openstack/nova/+/96090
> > >
> > > Most (all?) of our CI currently running with [libvirt]virt_type=qemu
> > > uses the full Cirros 0.5.2 image. Does anyone have any suggestions on
> > > the best way of modifying the image(s) we use in CI to use the
> > > no_timer_check kernel command line arg?
> >
> > The best way is probably to update the image upstream and then
> > update the cirros version in our tests?
> > https://github.com/cirros-dev/cirros/blob/master/src/boot/grub/menu.lst#L10
> > or maybe with a kernel build flag? Smoser does note in 1312199 above
> > that baking this into the image is an option though that was some
> > time ago.
>
> > If you want to modify the existing images instead it would probably
> > be a good idea to have something like devstack do it rather than the
> > CI system so that people running tools like devstack don't end up
> > with different images outside of the CI system.
> 
> +1 on both the approaches. With slight preference to just modify
> cirros upstream - it's not a production image so we can tweak it to
> suit kvm-less qemu constraints without worry.

Okay I can try both for the time being as I'm not entirely convinced
that Cirros upstream will accept the change, removing the devstack
change if they ever do.

Thanks for the input both!

-- 
Lee Yarwood                 A5D1 9385 88CB 7E5F BE64  6618 BCA6 6E33 F672 2D76
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