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[egoust <ustinov16@xxxxxxxxx>]

In our case we have specific Virtual Network Function images which
require deployment with 1 NUMA node topology. Some of them require sr-
iov ports and some not.

As from my point of view, NUMA scheduling could be more advanced and
instance without pci device request should be placed on NUMA node with
no PCI device attached. As example it could be an extra_spec for flavor
to specify that guest NUMA nodes should be bind to host NUMA nodes with
no associated with them PCI devices in pci_passthrough_whitelist

** Changed in: nova
       Status: Invalid => New

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https://bugs.launchpad.net/bugs/1614882

Title:
  NUMA node scheduling problem

Status in OpenStack Compute (nova):
  New

Bug description:
  Description
  ===========

  Instances without pci passthrough requests can overfill host NUMA
  nodes with dedicated for pci passthrough PCI devices. Instances placed
  on such NUMA nodes despite that there are plenty free resources in
  other host NUMA nodes. Such scheduling can lead to situation that
  further deployment of an instance with pci passthrough request will
  fail because of unavailable capacity in required NUMA node.

  Steps to reproduce
  ==================
  Test host with 2 NUMA nodes and PCI device attached to NUMA node 0.

  Create a flavor with hw:cpu_policy=dedicated

  Spawn several instances without pci passthrough with overall memory
  allocation equal memory capacity for NUMA node 0.

  Then deploy instance with sr-iov port. Scheduling fails with following
  error:

  2016-08-18 11:17:15.470 55110 DEBUG nova.compute.manager [req-c6d96425
  -e98b-4a63-8289-e56c40ac46d9 bb8e586fd1264034885fef3aae39e777
  b770743f66c44840a999cc8cf60916cd - - -] [instance:
  b4470025-2a59-4772-9990-a96b55966214] Build of instance
  b4470025-2a59-4772-9990-a96b55966214 was re-scheduled: Insufficient
  compute resources: Requested instance NUMA topology together with
  requested PCI devices cannot fit the given host NUMA topology.
  _do_build_and_run_instance /usr/lib/python2.7/site-
  packages/nova/compute/manager.py:1945

  Environment
  ===========
  Mitaka release
  Nova: 13.0.0

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