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StatefulSets for Databases¶

KubernetesStatefulSetDatabase 3 min read

StatefulSets for stateful applications in Kubernetes. Ordered deployment, stable network identity.

Why StatefulSet?¶

Unlike Deployments: stable hostname (pod-0, pod-1), ordered creation/deletion, persistent volumes per pod.

Example¶

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: postgres
spec:
  serviceName: postgres
  replicas: 3
  selector:
    matchLabels: {app: postgres}
  template:
    metadata:
      labels: {app: postgres}
    spec:
      containers:
        - name: postgres
          image: postgres:16
          ports: [{containerPort: 5432}]
          volumeMounts:
            - {name: data, mountPath: /var/lib/postgresql/data}
  volumeClaimTemplates:
    - metadata: {name: data}
      spec:
        accessModes: [ReadWriteOnce]
        resources: {requests: {storage: 100Gi}}

Headless Service¶

StatefulSet requires a headless service (clusterIP: None) for DNS records: postgres-0.postgres.default.svc.cluster.local

Summary¶

StatefulSet for databases, message queues and other stateful workloads. Consider managed DB (RDS, Cloud SQL) for simpler operations.

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