Open Stack

----- Original Message -----
> From: "Steve Gordon" <sgordon at redhat.com>
> To: "David Moreau Simard" <dms at redhat.com>
> Cc: "OpenStack Development Mailing List (not for usage questions)" <openstack-dev at lists.openstack.org>, "OpenStack
> Operators" <openstack-operators at lists.openstack.org>
> Sent: Tuesday, December 13, 2016 11:06:48 PM
> Subject: Re: [Openstack-operators] [all] Known issue with CentOS 7.3 and	qemu-kvm(-ev) 2.6.0
> 
> ----- Original Message -----
> > From: "David Moreau Simard" <dms at redhat.com>
> > To: "OpenStack Development Mailing List (not for usage questions)"
> > <openstack-dev at lists.openstack.org>, "OpenStack
> > Operators" <openstack-operators at lists.openstack.org>
> > Sent: Tuesday, December 13, 2016 6:13:12 PM
> > Subject: [Openstack-operators] [all] Known issue with CentOS 7.3 and
> > 	qemu-kvm(-ev) 2.6.0
> > 
> > Hi,
> > 
> > CentOS 7.3 was released yesterday and a newer version of qemu-kvm-ev
> > was shipped as part of this release if you have the CentOS
> > Virtualization SIG repositories enabled.
> 
> Isn't the issue that the newer version of qemu-kvm-ev (2.6.0) *hasn't*
> shipped yet? E.g. it's not in:
> 
>     http://mirror.centos.org/centos/7/virt/x86_64/kvm-common/
> 
> Hence the mismatch is created because the CentOS repos contain Libvirt 2.0.0
> but not a matching qemu-kvm-ev build (yet).
> 
> Thanks,
> 
> Steve

Just to elaborate on the above, for there are two potential scenarios where you will potentially hit "qemu-kvm: CPU feature arat not found":

1) When using virt_type="qemu", CentOS 7 1611 (Libvirt 2.0.0). In this case the corrective action for now appears to be as David noted, this is the scenario that is most likely hitting the noted CI jobs.

2) When using virt_type="kvm", CentOS 7 1611 (Libvirt 2.0.0) with qemu-kvm-ev < 2.6.0. In this case the corrective action based on https://bugzilla.redhat.com/show_bug.cgi?id=1371617 is actually to install qemu-kvm-ev 2.6.0, this is the scenario most likely to hit users.

I wanted to highlight this because David is (quite rightly) focusing on resolving (1) to get the CI jobs impacted moving, but it's quite possible many users will actually be hitting (2).

Thanks,

Steve

> > If you're using RDO >= Newton, you will have this repository enabled.
> > It was not yet enforced in the Mitaka release so you might or might
> > not have it, depending on your deployment.
> > Older releases of OpenStack may also be affected but they are not
> > proactively tested anymore due to EOL.
> > 
> > There is currently a known issue when using the following
> > configuration in nova for compute:
> > ==
> > virt_type=qemu
> > cpu_mode=host-model
> > ==
> > 
> > This combination will yield in failed attempts at creating instances
> > and you will see errors like these in nova-compute.log [1] or the
> > libvirt logs [2].
> > The problem boils down to libvirt trying to pass a cpu extension that
> > is unknown to qemu:
> > ==
> > qemu-kvm: CPU feature arat not found
> > ==
> > 
> > There is a bugzilla [3] for this issue but in the meantime users are
> > encouraged to work around the issue by setting "cpu_mode=none" if they
> > are using the qemu (not KVM) hypervisor.
> > Please note that Nova defaults the 'cpu_mode' parameter to
> > 'host-model' [4] if 'cpu_mode' is not explicitely configured and
> > 'virt_type' is 'qemu' so if you're running into this issue, you will
> > need to explicitely configure it.
> > 
> > [1]:
> > http://logs.openstack.org/76/409476/4/check/gate-puppet-openstack-integration-4-scenario003-tempest-centos-7/8881991/logs/nova/nova-compute.txt.gz#_2016-12-13_16_39_50_832
> > [2]:
> > http://logs.openstack.org/76/409476/4/check/gate-puppet-openstack-integration-4-scenario003-tempest-centos-7/8881991/logs/libvirt/qemu/instance-00000001.txt.gz
> > [3]: https://bugzilla.redhat.com/show_bug.cgi?id=1371617
> > [4]:
> > http://git.openstack.org/cgit/openstack/nova/tree/nova/virt/libvirt/driver.py?id=146b27f22327f8d60c1017c22ccf18d0e16f1eb7#n3411
> > 
> > David Moreau Simard
> > Senior Software Engineer | Openstack RDO
> > 
> > dmsimard = [irc, github, twitter]
> > 
> > _______________________________________________
> > OpenStack-operators mailing list
> > OpenStack-operators at lists.openstack.org
> > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-operators
> > 
> 
> 

-- 
Steve Gordon,
Principal Product Manager,
Red Hat OpenStack Platform