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[Chris Friesen <chris.friesen@xxxxxxxxxxxxx>]

** Changed in: nova
       Status: In Progress => Invalid

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https://bugs.launchpad.net/bugs/1484742

Title:
  NUMATopologyFilter doesn't account for CPU/RAM overcommit

Status in OpenStack Compute (nova):
  Invalid

Bug description:
  There seems to be a bug in the NUMATopologyFilter where it doesn't
  properly account for cpu_allocation_ratio or ram_allocation_ratio.
  (Detected on stable/kilo, not sure if it applies to current master.)

  To reproduce:

  1) Create a flavor with a moderate number of CPUs (5, for example) and
  enable hugepages by setting   "hw:mem_page_size=2048" in the flavor
  extra specs.  Do not specify dedicated CPUs on the flavor.

  2) Ensure that the available compute nodes have fewer CPUs free than
  the number of CPUs in the flavor above.

  3) Ensure that the "cpu_allocation_ratio" is big enough that
  "num_free_cpus * cpu_allocation_ratio" is more than the number of CPUs
  in the flavor above.

  4) Enable the NUMATopologyFilter for the nova filter scheduler.

  5) Try to boot an instance with the specified flavor.

  This should pass, because we're not using dedicated CPUs and so the
  "cpu_allocation_ratio" should apply.  However, the NUMATopologyFilter
  returns 0 hosts.

  It seems like the NUMATopologyFilter is failing to properly account
  for the cpu_allocation_ratio when checking whether an instance can fit
  onto a given host.

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