yahoo-eng-team team mailing list archive

[Thierry Carrez <thierry.carrez+lp@xxxxxxxxx>]

** Changed in: nova
       Status: Fix Committed => Fix Released

** Changed in: nova
    Milestone: None => havana-2

-- 
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/1189557

Title:
  Scheduler AZ filter should use cached values of host to AZ mapping

Status in OpenStack Compute (Nova):
  Fix Released

Bug description:
  If the scheduler is creating multiple instances in the same request it
  will re-run each filter for each host for each instance.

  In the case of the AZ filter, this currently includes a DB look up to
  get the AZ value from the aggregate - although this value isn't going
  to change on successive runs.

  Where there are a lot of hosts this can take several seconds for each
  run of the filter.   When repeating this say 100 times (to create 100
  instances) the total time taken by the scheduler can exceed the
  service timeout interval, and so hosts start getting dropped by the
  compute filter because it looks as if the last service update (cached
  by the scheduler at the start of the run has now expired).

  There seem to be two possible solutions here:
  i) Change the AZ filter to use a cached value  (Would be simple as the availability zone class already has caching)

  ii) Change the filter mechanism so that filters can be defined so that
  they need only to be run once for each scheduler request

  
   The second approach seems more general

To manage notifications about this bug go to:
https://bugs.launchpad.net/nova/+bug/1189557/+subscriptions