Track resources using Placement

This proposes to change to use Placement service for tracking
baremetal resources

Partially Implements: bp track-resources-using-placement

Change-Id: I4d8483b5d8fb04db091d72f37b40925b016c953b

specs/pike/approved/track-resources-using-placement.rst

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+..
+ This work is licensed under a Creative Commons Attribution 3.0 Unported
+ License.
+
+ http://creativecommons.org/licenses/by/3.0/legalcode
+
+=================================================
+Track baremetal resources using Placement service
+=================================================
+
+https://blueprints.launchpad.net/mogan/+spec/track-resources-using-placement
+
+This spec proposes using placement service for baremetal resources tracking.
+The placement service is intended to enable more effective accounting of
+resources and better scheduling of various entities in the cloud.
+
+
+Problem description
+===================
+
+We'd like to be able to schedule not only based on baremetal node resources,
+but also other resources in the cloud like shared storage. So we need to move
+to this more generic modeling of quantitative and qualitative resources.
+
+Use Cases
+---------
+
+Cloud operators want to be able to add new classes of resources to the system
+with a generic model and do so without any downtime caused by database schema
+migrations.
+
+
+Proposed change
+===============
+
+* We will define new resource classes for each node accodring to what is in
+  the ironic node's `resource_class` attribute.
+
+* Generate the resource provider for each baremetal node to track the
+  resources, set provider's inventory to a single record of custom resource
+  class. The resource tracking model is as the following::
+
+    resource classes:               CUSTOM_GOLD                    CUSTOM_SILVER
+                                    /         \                          |
+    resource providers: baremetal_node1     baremetal_node2       baremetal_node2
+                               |                   |                     |
+    inventories:       {'CUSTOM_GOLD': 1}   {'CUSTOM_GOLD': 1}  {'CUSTOM_SILVER': 1}
+
+* As we consume baremetal nodes atomically not piecemeal, so the inventory data
+  for such resource provider should be as::
+
+    Inventory: {
+        "resource_provider_id": 1,
+        "resource_class_id": 10001,
+        "total": 1,
+        "reserved": 0,
+        "min_unit": 1,
+        "max_unit": 1,
+        "step_size": 1,
+        "allocation_ratio": 1.0
+    }
+
+* For **qualitative** aspects of the baremetal resources, the placement traits
+  is targeted to support this, we can use custom traits to define what the
+  resource provider's characteristics is.
+
+* Modify resource tracker to periodically report node resources to placement
+  service, which will also remove the orphan nodes.
+
+* Needs to change filter_scheduler to call placement REST API to get filtered
+  nodes like below::
+
+    GET /resource_providers?resources=CUSTOM_GOLD:1
+
+
+Alternatives
+------------
+
+None
+
+Data model impact
+-----------------
+
+This will remove ComputeNodes and ComputePorts objects.
+
+REST API impact
+---------------
+
+None
+
+Security impact
+---------------
+
+None
+
+Notifications impact
+--------------------
+
+None
+
+Other end user impact
+---------------------
+
+None
+
+Performance Impact
+------------------
+
+None
+
+Other deployer impact
+---------------------
+
+This will break all mogan deployments as we migrate resources tracking to
+another service, but as we don't have any release yet, so we suppose there's
+no mogan deployment.
+
+Developer impact
+----------------
+
+None
+
+Implementation
+==============
+
+Assignee(s)
+-----------
+
+Primary assignee:
+    liusheng
+
+Other contributors:
+    zhenguo
+
+Work Items
+----------
+
+* Add placement client and config options.
+* Update resource tracker to report resources to placement.
+* Adjust scheuler filters for such refactoring.
+* remove the compute_nodes and compute_ports resources objects.
+* Add UT and docs.
+
+Dependencies
+============
+
+None
+
+Testing
+=======
+
+Unit Testing will be added.
+
+Documentation Impact
+====================
+
+Docs about new flavor will be added.
+
+References
+==========
+
+None