[openstack-dev] [nova] [placement] resource providers update 36

Chris Dent cdent+os at anticdent.org
Fri Oct 6 13:21:57 UTC 2017

Update 37 is struggling to contain itself, too much code associated
with placement!

# Most Important^wRecent

Discussion last night uncovered some disagreement and confusion over
the content of the Selection object that will be used to send
alternate destination hosts when doing builds. The extent to which an
allocation request is not always opaque and the need to be explicit
about microversions was clarified, so edleafe is going to make some
adjustments, after first resolving the prerequisite code (alternate
hosts: https://review.openstack.org/#/c/486215/ ).

# What's Changed

Nested providers spec merged, selection objects spec merged (but see
above and below), alternate hosts spec merge, request traits in nova
spec merged, minimal cache header spec merged, POST /allocations spec

* http://specs.openstack.org/openstack/nova-specs/specs/queens/approved/migration-allocations.html
* http://specs.openstack.org/openstack/nova-specs/specs/queens/approved/nested-resource-providers.html
* http://specs.openstack.org/openstack/nova-specs/specs/queens/approved/placement-cache-headers.html
* http://specs.openstack.org/openstack/nova-specs/specs/queens/approved/post-allocations.html
* http://specs.openstack.org/openstack/nova-specs/specs/queens/approved/request-traits-in-nova.html
* http://specs.openstack.org/openstack/nova-specs/specs/queens/approved/return-alternate-hosts.html
* http://specs.openstack.org/openstack/nova-specs/specs/queens/approved/return-selection-objects.html

There are additional specs not yet merged, placement related, some of
which the above depend on, that need some attention.

* https://review.openstack.org/#/c/502306/
   Network bandwidth resource provider

* https://review.openstack.org/#/c/507052/
   Support traits in the Ironic driver

* https://review.openstack.org/#/c/508164/
   Add spec for symmetric GET and PUT of allocations
   (The POST /allocations spec depends on this one)

* https://review.openstack.org/#/c/509136/
   Fix issues for post-allocations spec

* https://review.openstack.org/#/c/504540/
   Spec for limiting GET /allocation_candidates

* https://review.openstack.org/#/c/497713/
   Add trait support in the allocation candidates API

# Main Themes

## Nested Resource Providers

While working on nested resource providers it became clear there was
a lot of mixed up crusted in the resource provider objects, so before
the nested work there is now


which is a stack of cleanups to how the SQL is managed in there. When
that is done, the conflicts at


will be resolved and nested work will continue.

## Migration allocations

The migration allocations work is happening at:


Management of those allocations currently involves some raciness,
birthing the specs (above) to allow POST /allocations, some of the
code for that is in progress at


## Alternate Hosts

We want to be able to do retries within cells, so we need some
alternate hosts when returning a destination that are structured
nicely for RPC:


# Other Stuff

* https://review.openstack.org/#/c/508149/
   A spec in neutron for QoS minimum bandwidth allocation in Placement

There's plenty of other other stuff too, but much of it is covered in
the links above to avoid a tyranny of choice, I'll just leave it off
for now. There's plenty of existing stuff to think about.

# End

Your prize this week is vegetable tempura.

Chris Dent                      (⊙_⊙')         https://anticdent.org/
freenode: cdent                                         tw: @anticdent

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