DevOps: What is Kubernetes StatefulSet?

1apiVersion: apps/v1
2kind: StatefulSet
3metadata:
4  name: postgres
5spec:
6  serviceName: postgres
7  replicas: 3
8  selector:
9    matchLabels:
10      app: postgres
11  template:
12    metadata:
13      labels:
14        app: postgres
15    spec:
16      containers:
17      - name: postgres
18        image: postgres:16
19        volumeMounts:
20        - name: data
21          mountPath: /var/lib/postgresql/data
22  volumeClaimTemplates:
23  - metadata:
24      name: data
25    spec:
26      accessModes: ["ReadWriteOnce"]
27      resources:
28        requests:
29          storage: 10Gi