yahoo-eng-team team mailing list archive

[Chris Friesen <chris.friesen@xxxxxxxxxxxxx>]

Public bug reported:

When booting an instance it's possible to force it to be placed on a
specific host using the  "--availability-zone nova:host" syntax.

If you do this, the code at 
https://github.com/openstack/nova/blob/master/nova/scheduler/host_manager.py#L581 will return early rather than call self.filter_handler.get_filtered_objects()

Based on discussions at the PTG with Dan Smith, the simplest solution
would be to create a flag similar to RUN_ON_REBUILD which would be
applied to the various scheduler filters in a manner analogous to how
rebuild is handled now.

Presumably we'd want to call something like this during the instance
boot code to ensure we hit the existing "if not check_type" at L581:

request_spec.scheduler_hints['_nova_check_type'] = ['build']


Then in the various critical filers (NUMATopologyFilter for example, and PciPassthroughFilter, and maybe some others like ComputeFilter) we could define something like "RUN_ON_BUILD = True" to ensure that they run even when forcing a host.

** Affects: nova
     Importance: Undecided
         Status: New


** Tags: compute scheduler

-- 
You received this bug notification because you are a member of Yahoo!
Engineering Team, which is subscribed to OpenStack Compute (nova).
https://bugs.launchpad.net/bugs/1754782

Title:
  we skip critical scheduler filters when forcing the host on instance
  boot

Status in OpenStack Compute (nova):
  New

Bug description:
  When booting an instance it's possible to force it to be placed on a
  specific host using the  "--availability-zone nova:host" syntax.

  If you do this, the code at 
  https://github.com/openstack/nova/blob/master/nova/scheduler/host_manager.py#L581 will return early rather than call self.filter_handler.get_filtered_objects()

  Based on discussions at the PTG with Dan Smith, the simplest solution
  would be to create a flag similar to RUN_ON_REBUILD which would be
  applied to the various scheduler filters in a manner analogous to how
  rebuild is handled now.

  Presumably we'd want to call something like this during the instance
  boot code to ensure we hit the existing "if not check_type" at L581:

  request_spec.scheduler_hints['_nova_check_type'] = ['build']

  
  Then in the various critical filers (NUMATopologyFilter for example, and PciPassthroughFilter, and maybe some others like ComputeFilter) we could define something like "RUN_ON_BUILD = True" to ensure that they run even when forcing a host.

To manage notifications about this bug go to:
https://bugs.launchpad.net/nova/+bug/1754782/+subscriptions