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nova-specs
Code Issues Proposed changes

Update spec: filtering of alloc candidates by forbidden aggregates 

Earlier, it was decided to sync traits that were set to the aggregates
in Nova to the compute node resource providers in Placement.
But there are issues especially when you want to remove traits from
aggregates or remove hosts from aggregates.

For example, Isolating hyperthreading hosts. Assume you have already
configured compute node resource providers with
"HW_CPU_HYPERTHREADING" trait in placement and now you are enabling
scheduler forbidden aggregates pre-request filter. So, operator will
simply add "HW_CPU_HYPERTHREADING" trait to the aggregate and add
all hyperthreading hosts to it. Later, if operator want to remove
some hosts from aggregate, the trait "HW_CPU_HYPERTHREADING" will
also be removed from host even though the host is still capable of
providing hyperthreading.

The specs is updated after consensus from community to avoid
automatic syncing of traits. Operator will need to set these traits
manually in placement service.

Implements: blueprint placement-req-filter-forbidden-aggregates
Change-Id: I9acd053aab766e8cf980f0093d642cdc0725b0f8
This commit is contained in:
tpatil 2019-06-17 04:36:41 +00:00
parent dbe78072c1
commit c8fdf0461b
1 changed files with 8 additions and 3 deletions
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11
specs/train/approved/placement-req-filter-forbidden-aggregates.rst
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@ -200,10 +200,13 @@ command:
``nova-manage placement sync_aggregates``
We will modify this command to synchronize traits to placement and add these
This spec will not sync traits to placement and it will not add these
traits to the compute node resource providers that belongs to the aggregates
if aggregate has metadata key=value pair with syntax
`trait:<trait_name>=required`.
which has metadata key=value pair with syntax `trait:<trait_name>=required`.
Please refer to the `Nova meeting log`_ and `Mailing thread`_ where we have
mutually agreed to let operator sync these traits manually. In future,
if required, a utility tool can be developed for syncing these traits which is
outside the scope of this spec.
Implementation
==============
@ -252,6 +255,8 @@ References
.. _Strict-isolation-group-hosts-images: https://review.openstack.org/#/c/381912/17/specs/rocky/approved/strict_isolation_of_group_of_hosts_for_image.rst
.. _mirror_nova_host_aggregates: https://specs.openstack.org/openstack/nova-specs/specs/rocky/implemented/placement-mirror-host-aggregates.html
.. _IsolatedHostsFilter: https://docs.openstack.org/nova/latest/admin/configuration/schedulers.html#isolatedhostsfilter
.. _Nova meeting log: http://eavesdrop.openstack.org/meetings/nova/2019/nova.2019-06-13-14.00.log.html#l-267
.. _Mailing thread: http://lists.openstack.org/pipermail/openstack-discuss/2019-June/006950.html
.. Rocky PTG: https://etherpad.openstack.org/p/nova-ptg-rocky
.. Stein PTG: https://etherpad.openstack.org/p/nova-ptg-stein