Kubernetes StatefulSet Manifest

External

• https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.16/#statefulset-v1-apps

Internal

• StatefulSet

Example

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: postgresql
  labels:
    color: blue
spec:
  replicas: 1
  serviceName: postgresql-headless
  selector:
    matchLabels: # all labels declared here must exists and have same corresponding values in the template.metadata.labels section below
      app: postgresql
      role: master   
  podManagementPolicy: OrderedReady
  updateStrategy: 
    type: RollingUpdate
  template:
    metadata:
      name: postgresql
      labels: # this section may declare additional labels to .spec.selector.matchLabels
        app: postgresql
        role: master
        color: blue 
    spec:
      containers:
        - ...
      initContainers:
        - ...
      dnsPolicy:  ClusterFirst
      restartPolicy: Always
      schedulerName: default-scheduler
      securityContext: ...
      terminationGracePeriodSeconds: ...
  volumeClaimTemplates:
    # for details see Persistent Volume Claim Manifest
    - metadata:
        name: data
      spec:
        volumeMode: Filesystem
        # Optionally a storage class can be specified, otherwise the default storage class will be used
        # storageClassName: manual-local-storage
        accessModes:
          - ReadWriteOnce
        resources:
          requests:
            storage: 8Gi

.spec Elements

.spec.selector

.spec.selector.matchLabels

The labels declared in this section must exist also in the .spec.template.metadata.labels section, and have the same corresponding values, otherwise the StatefulSet deployment will fail with "spec.template.metadata.labels: Invalid value: [...]: 'selector' does not match template 'labels'". Note that the .spec.template.metadata.labels section may declare additional labels.

When the corresponding persistent volume claims are created, they will be automatically get all the labels declared in this section. For more details, see:

Labels on a Persistent Volume Claim created from the Persistent Volume Claim Template

volumeClaimTemplates

volumeClaimTemplates is a list of persistent volume claim specifications, defining persistent volume claims that pods are allowed to reference. The StatefulSet controller is responsible for mapping network identities to claims in a way that maintains the identity of a pod. Every claim in this list must have at least one name-matching volumeMount in one container in the template. The name of the claim is specified as .metadata.name.A claim in this list takes precedence over any volumes in the template, with the same name.

For more details on StatefulSet persistent volume claims see:

StatefulSet Persistent Volume Claim Templates

For more details on persistent claim manifests, see:

Persistent Volume Claim Manifest