openstack
/
nova-specs
Code Issues Proposed changes

Allow for merging traits and aggregates 

Per discussions at the PTG [1] as concluded in IRC [2][3][4],
update_provider_tree needs to set and unset only the traits and
aggregate associations it "owns", rather than replacing them wholesale.
To facilitate this, we're adding ProviderTree methods add_traits,
remove_traits, add_aggregates, and remove_aggregates.

[1] Awkwardly pasted, since no etherpad permalink: http://paste.openstack.org/raw/698758/
[2] http://eavesdrop.openstack.org/meetings/nova_scheduler/2018/nova_scheduler.2018-03-12-14.00.log.html#l-217
[3] http://eavesdrop.openstack.org/irclogs/%23openstack-nova/%23openstack-nova.2018-03-12.log.html#t2018-03-12T16:08:09
[4] http://eavesdrop.openstack.org/irclogs/%23openstack-nova/%23openstack-nova.2018-03-12.log.html#t2018-03-12T18:29:56

Change-Id: I0a1ffa4e3849ea5ed9f5252c38e5cf646eebfd62
This commit is contained in:
Eric Fried 2018-03-12 13:05:33 -05:00
parent 818976a685
commit 61152b511c
1 changed files with 54 additions and 6 deletions
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60
specs/rocky/approved/update-provider-tree.rst
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@ -53,7 +53,10 @@ parameters:
therefore be modified without locking/concurrency considerations. Note,
however, that it may contain providers not directly owned/controlled by the
compute host. Care must be taken not to remove or modify such providers
inadvertently.
inadvertently. In addition, providers may be associated with traits and/or
aggregates maintained by outside agents. The ``update_provider_tree`` must
therefore also be careful only to add/remove traits/aggregates it explicitly
controls.
* String name of the compute node (i.e. ``ComputeNode.hypervisor_hostname``)
for which the caller is updating providers and inventory. Drivers may use
this to help identify the compute node provider in the ProviderTree. Drivers
@ -112,8 +115,11 @@ Some of the methods which may be useful are as follows:
* ``remove``: Remove a provider **and its descendants** from the tree. Use
caution in multiple-ownership scenarios.
* ``update_inventory``: Set the inventory for a provider.
* ``update_traits``: Set the traits for a provider.
* ``update_aggregates``: Set the aggregates for a provider.
* ``add_traits``, ``remove_traits``: Set/unset virt-owned traits for a provider
(see `ProviderTree.add_traits and .remove_traits`_).
* ``add_aggregates``, ``remove_aggregates``: Set/unset virt-owned aggregate
associations for a provider (see `ProviderTree.add_aggregates and
.remove_aggregates`_).
.. note:: There is no supported mechanism for ``update_provider_tree`` to
effect changes to allocations. This is intentional: in Nova,
@ -152,7 +158,7 @@ would become:
Porting from get_traits
~~~~~~~~~~~~~~~~~~~~~~~
To replace ``get_traits``, developers should use the
``ProviderTree.update_traits`` method, specifying the compute node as the
``ProviderTree.add_traits`` method, specifying the compute node as the
provider and the same traits as returned by ``get_traits``. For example:
.. code::
@ -166,8 +172,8 @@ would become:
.. code::
def update_provider_tree(self, provider_tree, nodename):
traits = ['HW_CPU_X86_AVX', 'HW_CPU_X86_AVX2', 'CUSTOM_GOLD']
provider_tree.update_traits(nodename, traits)
provider_tree.add_traits(
nodename, 'HW_CPU_X86_AVX', 'HW_CPU_X86_AVX2', 'CUSTOM_GOLD')
SchedulerReportClient.update_from_provider_tree
-----------------------------------------------
@ -222,6 +228,48 @@ to:
except NotImplementedError:
pass
ProviderTree.add_traits and .remove_traits
------------------------------------------
Since outside agents (e.g. operators) need to be able to set and unset
traits which are outside of the purview of the virt driver,
`ComputeDriver.update_provider_tree`_ needs to be able to add and remove traits
explicitly, rather than simply overwriting the entire set of traits for a given
provider. To facilitate this, we will add the following methods to
ProviderTree:
.. code::
def add_traits(self, name_or_uuid, \*traits)
def remove_traits(self, name_or_uuid, \*traits)
Arguments:
* ``name_or_uuid``: Either the name or the UUID of the resource provider whose
traits are to be affected.
* ``traits``: String names of traits to add or remove. Any other traits
associated with the provider are untouched.
ProviderTree.add_aggregates and .remove_aggregates
--------------------------------------------------
Since outside agents (e.g. operators) need to be able to set and unset
aggregate associations which are outside of the purview of the virt driver,
`ComputeDriver.update_provider_tree`_ needs to be able to add and remove
aggregate associations explicitly, rather than simply overwriting the entire
set of aggregate associations for a given provider. To facilitate this, we
will add the following methods to ProviderTree:
.. code::
def add_aggregates(self, name_or_uuid, \*aggregates)
def remove_aggregates(self, name_or_uuid, \*aggregates)
Arguments:
* ``name_or_uuid``: Either the name or the UUID of the resource provider whose
aggregates are to be affected.
* ``aggregates``: String UUIDs of aggregates to add or remove. Any other
aggregates associated with the provider are untouched.
Alternatives
------------
* Continue to provide piecemeal methods in the spirit of ``get_inventory``