nova/releasenotes/notes/multiple-scheduler-workers-3e5ac0d86f436338.yaml
Rui Chen 0989878165 Scheduler multiple workers support
Multiple process workers support for nova-scheduler.

Since blueprint placement-claims in Pike, the FilterScheduler
uses the Placement service to create resource allocations (claims)
against a resource provider (i.e. compute node) chosen
by the scheduler. That reduces the risk of scheduling collisions
when running multiple schedulers, so this change adds the ability
to set multiple scheduler workers like for the nova-osapi_compute
and nova-conductor services.

Co-Authored-By: Matt Riedemann <mriedem.os@gmail.com>

Change-Id: Ifdcd363d7bc22e73d76d69777483e5aaff4036e3
2018-02-18 19:10:55 -05:00

26 lines
1.2 KiB
YAML

---
features:
- |
It is now possible to configure multiple *nova-scheduler* workers via the
``[scheduler]workers`` configuration option. By default, the option runs
``ncpu`` workers if using the ``filter_scheduler`` scheduler driver,
otherwise the default is 1.
Since `blueprint placement-claims`_ in Pike, the FilterScheduler
uses the Placement service to create resource allocations (claims)
against a resource provider (i.e. compute node) chosen by the scheduler.
That reduces the risk of scheduling collisions when running multiple
schedulers.
Since other scheduler drivers, like the CachingScheduler, do not
use Placement, it is recommended to set workers=1 (default) for those
other scheduler drivers.
.. _blueprint placement-claims: https://specs.openstack.org/openstack/nova-specs/specs/pike/implemented/placement-claims.html
upgrade:
- |
The new ``[scheduler]workers`` configuration option defaults to ``ncpu``
workers if using the ``filter_scheduler`` scheduler driver. If you are
running *nova-scheduler* on the same host as other services, you may want
to change this default value, or to otherwise account for running other
instances of the *nova-scheduler* service.