OpenStack Placement

openstack Coordination serviceopenstack-placement

Tracks resource provider inventories, usages and traits so services can find where a workload fits.

Provider: openstack
Kind: Coordination service
Category: Operations
Official docs: https://docs.openstack.org/placement/latest/

Properties · 2 set by this component

property	type	values	required	kind default	this component
consensus	enum	none \| raft \| paxos \| zab	no	none	inherited
managed	boolean	—	no	false	▸ false
nodes	integer	—	no	—	inherited
replicated	boolean	—	no	false	inherited
resourceClasses · component property	boolean	—	no	true	inherited
role	enum	metadata \| lock \| discovery \| placement \| sharding \| leader-election \| config	yes	—	▸ placement
standalone · component property	boolean	—	no	true	inherited
traits · component property	boolean	—	no	true	inherited

Rules that apply · 2

Every rule whose selector covers this component's kind or its category. Whether a rule fires depends on the design: its properties, its edges and its groups.

Shared dependency without redundancyerror

shared-dependency-without-redundancy

The design requires redundant discovery, but this DNS or coordination service, which everything depends on, runs on a single provider or a single replica. Its failure is the whole system's failure.

— all of these hold:
— the design requirement `availability.discoveryRedundant` is true
— any of these hold:
— the node's `redundantProviders` is false
— the node's `replicated` is false

Stateful engine pinned to a single zoneerror

stateful-engine-pinned-to-single-zone

A matching engine, coordination service or event store living in exactly one availability zone, with no failover and no replication, is lost with that zone. Everything that depends on it stops with it.

— all of these hold:
— the node sits inside exactly 1 availability-zone group
— any of these hold:
— the node's `failover` is "none"
— the node's `replicated` is false
— the node's `replication` is "none"

Use it in a design

nodes:
  - { id: "placement", component: "openstack-placement" }

Other Coordination service products · 17

Source

1# yaml-language-server: $schema=../../schema/component.schema.json
2# OpenStack Placement: "a REST API stack and data model used to track resource provider
3# inventories and usages, along with different classes of resources" ("Placement API").
4# It records resource providers (compute nodes, storage pools, IP allocation pools), their
5# inventories in resource classes such as VCPU, MEMORY_MB and DISK_GB, and qualitative traits;
6# Nova and other services ask it where a workload can fit. Extracted from Nova into its own
7# repository in Stein (19.0.0) after arriving in Newton (14.0.0).
8schemaVersion: "1"
9type: "component"
10id: "openstack-placement"
11kind: "coordination-service"
12provider: "openstack"
13docs: "https://docs.openstack.org/placement/latest/"
14defaults:
15  role: "placement"
16  managed: false
17properties:
18  resourceClasses:
19    type: "boolean"
20    default: true
21  traits:
22    type: "boolean"
23    default: true
24  standalone:
25    type: "boolean"
26    default: true

The same page as markdown, for an agent: /catalogue/components/openstack-placement.md