osc placement resource-provider aggregate

Resource provider aggregates

Each resource provider can be associated with one or more other resource providers in groups called aggregates. API calls in this section are used to list and update the aggregates that are associated with one resource provider.

Provider aggregates are used for modeling relationships among providers. Examples may include:

  • A shared storage pool providing DISK_GB resources to compute node providers that provide VCPU and MEMORY_MB resources.

  • Affinity/anti-affinity relationships such as physical location, power failure domains, or other reliability/availability constructs.

  • Groupings of compute host providers corresponding to Nova host aggregates or availability zones.

Note: Placement aggregates are not the same as Nova host aggregates and should not be considered equivalent.

The primary differences between Nova’s host aggregates and placement aggregates are the following:

  • In Nova, a host aggregate associates a nova-compute service with other nova-compute services. Placement aggregates are not specific to a nova-compute service and are, in fact, not compute-specific at all. A resource provider in the Placement API is generic, and placement aggregates are simply groups of generic resource providers. This is an important difference especially for Ironic, which when used with Nova, has many Ironic baremetal nodes attached to a single nova-compute service. In the Placement API, each Ironic baremetal node is its own resource provider and can therefore be associated to other Ironic baremetal nodes via a placement aggregate association.

  • In Nova, a host aggregate may have metadata key/value pairs attached to it. All nova-compute services associated with a Nova host aggregate share the same metadata. Placement aggregates have no such metadata because placement aggregates only represent the grouping of resource providers. In the Placement API, resource providers are individually decorated with traits that provide qualitative information about the resource provider.

  • In Nova, a host aggregate dictates the availability zone within which one or more nova-compute services reside. While placement aggregates may be used to model availability zones, they have no inherent concept thereof.

Usage: osc placement resource-provider aggregate <COMMAND>

Available subcommands: