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Version: 3.2

VolumePlacementStrategy CRD reference for OpenShift with FlashArray

Portworx provides a CustomResouceDefinition (CRD) called VolumePlacementStrategy. The specification for this CRD is composed of 4 main sections:

Additional Information:

replicaAffinity​

Schema​

Example use cases of replicaAffinity​
  • [Use SSD pools]/samples/k8s/volume-placement-ssd-sata-pool-spread-affinity.yaml)
  • [Use SSD and SATA and spread replicas evenly]/samples/k8s/volume-placement-ssd-sata-pool-spread-affinity.yaml)
  • [First replica SSD, others SATA]/samples/k8s/volume-placement-one-ssd-other-sata-pool.yaml)
  • [Place volume on specific nodes, example infra etc]/samples/k8s/volume-infra-node-affinity.yaml)
  • [Place volume only on racks 1, 2 and 3]/samples/k8s/volume-rack-1-2-3-affinity.yaml)

By default, Portworx automatically adds the following labels to each of its storage pools. These can be used for replica affinity rules to target replicas on a specific storage pool type:

  • iopriority
  • medium (Media Type)

replicaAntiAffinity​

Schema​

Example use cases​
  • [Antiaffinity to data pools and spread across racks]/samples/k8s/antiAffinityDataRacks.yaml)
  • [Antiaffinity to not use SATA pools]/samples/k8s/volume-placement-sata-pool-anti-affinity.yaml)

volumeAffinity​

Schema​

Example use cases​
  • [Collocate postgres volumes]/samples/k8s/volume-placement-postgres-volume-affinity.yaml)
  • [Place volume on DB type nodes or collocate with postgres volumes]/samples/k8s/volume-db-nodes-or-postgres-affinity.yaml)

volumeAntiAffinity​

Schema​

Example use cases​

[Do not collocate with other cassandra volumes]/samples/k8s/volume-placement-cassandra-volume-anti-affinity.yaml)

topologyKey​

If topologyKey is not set, by default the rule will avoid/colocate volumes at the node level using built-in unique node identifiers.

Portworx Built-in​

topologyKey can use the built-in key portworx.io/pool that is set automatically as a unique key/value on every Portworx pool. This can be used with volumeAffinity/volumeAntiAffinity to control volume placement at the pool level to work for individual pools.

Templates​

Parameter values in matchExpressions may use predefined templates. The VolumePlacementStrategy will automatically resolve these templates at provision time as detailed below:

  • key: namespace
    • ${pvc.namespace}
      • Replaced with namespace of the PersistentVolumeClaim that triggered provisioning
      • Example: [Do not collocate with other app volumes within the same namespace]/samples/k8s/volume-anti-affinity-namespace-template.yaml)
  • key: px/statefulset-pod
    • ${pvc.statefulset-pod}
      • Replaced with the StatefulSet pod name the PersistentVolumeClaim belongs to
      • Matches corresponding label key/value applied to the volume
      • Use this with multiple volumeClaimTemplates in a StatefulSet to relate volumes for the same replica pod to each other
      • Works with Immediate binding mode
      • Example: [Collocate volumes that belong to the same StatefulSet pod]/samples/k8s/statefulset-template-volume-affinity.yaml)
  • key: labelkey
    • ${pvc.labels.labelkey}
      • Portworx replaces any values in the template ${pvc.labels.labelkey} with the pvc.labels value for labelkey.
      • Example: [Label the volumes dynamically based on the PVC label field]/samples/k8s/volume-anti-affinity-dynamic-label-template.yaml)
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