Document NUMA support in nova

[OpenStack Infra]

https://review.openstack.org/115381
commit 1d17d4fc01a7b582b55e0dc3c9ad9dae7281675b
Author: Nikola Dipanov <email address hidden>
Date: Tue Aug 19 20:37:40 2014 +0200

    libvirt: Consider numa_topology when booting

    This patch hooks all the already introduced pieces together to enable
    NUMA aware placement of instances.

    The libvirt driver boot process now looks into the NUMA topology field
    of both instance and the host it is being booted on, and based on that
    adds some more configuration to the generated guest XML.

    In case the host is NUMA capable, but the instance has not requested
    a NUMA topology, we will try to pack the instance into a single cell.
    If that fails, currently we will not make further attempts (although
    an improvement could be to expose the underlying topology to the
    instance).

    In case the host is NUMA capable, and instance has requested a specific
    NUMA topology, we will try to pin the vCPUs of different instance NUMA
    cells to the corresponding host NUMA cells, and also expose the instance
    NUMA topology to the guest OS.

    We will still try to respect CONF.vcpu_pin_set option and avoid pinning
    to CPUs that are not in this set.

    DocImpact

    Change-Id: I611d44ab75475028f63c2b7f8a0d2ef37d85be6e
    Blueprint: virt-driver-numa-placement

[Gauvain Pocentek (gpocentek)]

I don't think we have documentation about how NUMA-capable hosts can be used, but this is something that probably needs a bit of information.

[Tom Fifield (fifieldt)]

Agreed - some general documentation about NUMA support (a new section in the admin guide or config reference) should be completed for this feature.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/219992

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/219992
Committed: https://git.openstack.org/cgit/openstack/openstack-manuals/commit/?id=9a2a1a375d9ff08f801112610f13108775fdf777
Submitter: Jenkins
Branch: master

commit 9a2a1a375d9ff08f801112610f13108775fdf777
Author: Lana Brindley <email address hidden>
Date: Thu Sep 3 15:09:54 2015 +1000

    Added section about NUMA

    Adds some conceptual information about NUMA, and discusses how nova
    considers NUMA topology when booting instances. (This is a starting point,
    I'm happy for people to move this to a different section, or change wording).

    Change-Id: I328831fb3aef9531ee924aa86726277b7eac0cb5
    Closes-Bug: 1369207

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/openstack-manuals 15.0.0 release.