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

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