Kubernetes service and deployment descriptor for Zookeeper

zookeeper.yaml

apiVersion: v1
kind: Service
metadata:
  name: zk
  labels:
    app: zk
    tier: backend
spec:
  # Lookup: dig -t srv _client._tcp.zk.default.svc.cluster.local
  ports:
  - port: 2181
    name: client
  - port: 2888
    name: server
  - port: 3888
    name: leader-election
  # Make the service headless (expose individual pods to DNS)
  clusterIP: None
  selector:
    app: zk
    tier: backend
---
apiVersion: v1
kind: ConfigMap
metadata:
  name: zk-config
  labels:
    app: zk
    tier: backend
data:
  jvm.heap: "512M"
  tick: "2000"
  init: "10"
  sync: "5"
  client.cnxns: "20"
  snap.retain: "3"
  purge.interval: "1"
---
apiVersion: policy/v1beta1
kind: PodDisruptionBudget
metadata:
  name: zk-budget
spec:
  selector:
    matchLabels:
      app: zk
      tier: backend
  minAvailable: 2
---
apiVersion: apps/v1beta1
kind: StatefulSet
metadata:
  name: zk
  labels:
    app: zk
    tier: backend
spec:
  serviceName: zk
  replicas: 3
  template:
    metadata:
      labels:
        app: zk
        tier: backend
      annotations:
        pod.alpha.kubernetes.io/initialized: "true"
        scheduler.alpha.kubernetes.io/affinity: >
          {
            "podAntiAffinity": {
              "requiredDuringSchedulingIgnoredDuringExecution": [{
                "labelSelector": {
                  "matchExpressions": [{
                    "key": "app",
                    "operator": "In",
                    "values": ["zk"]
                  }]
                },
                "topologyKey": "kubernetes.io/hostname"
              }]
            }
          }
    spec:
      containers:
      - name: k8szk
        image: gcr.io/google_samples/k8szk:v2
        resources:
          requests:
            memory: "1Gi"
            cpu: "250m"
          limits:
            memory: "1Gi"
            cpu: "500m"
        ports:
        - containerPort: 2181
          name: client
        - containerPort: 2888
          name: server
        - containerPort: 3888
          name: leader-election
        env:
        - name : ZK_REPLICAS
          value: "3"
        - name : ZK_HEAP_SIZE
          valueFrom:
            configMapKeyRef:
                name: zk-config
                key: jvm.heap
        - name : ZK_TICK_TIME
          valueFrom:
            configMapKeyRef:
                name: zk-config
                key: tick
        - name : ZK_INIT_LIMIT
          valueFrom:
            configMapKeyRef:
                name: zk-config
                key: init
        - name : ZK_SYNC_LIMIT
          valueFrom:
            configMapKeyRef:
                name: zk-config
                key: tick
        - name : ZK_MAX_CLIENT_CNXNS
          valueFrom:
            configMapKeyRef:
                name: zk-config
                key: client.cnxns
        - name: ZK_SNAP_RETAIN_COUNT
          valueFrom:
            configMapKeyRef:
                name: zk-config
                key: snap.retain
        - name: ZK_PURGE_INTERVAL
          valueFrom:
            configMapKeyRef:
                name: zk-config
                key: purge.interval
        - name: ZK_CLIENT_PORT
          value: "2181"
        - name: ZK_SERVER_PORT
          value: "2888"
        - name: ZK_ELECTION_PORT
          value: "3888"
        command:
        - sh
        - -c
        - zkGenConfig.sh && zkServer.sh start-foreground
        readinessProbe:
          exec:
            command:
            - "zkOk.sh"
          initialDelaySeconds: 15
          timeoutSeconds: 5
        livenessProbe:
          exec:
            command:
            - "zkOk.sh"
          initialDelaySeconds: 15
          timeoutSeconds: 5
        volumeMounts:
        - name: data
          mountPath: /var/lib/zookeeper
      securityContext:
        runAsUser: 1000
        fsGroup: 1000
  volumeClaimTemplates:
  - metadata:
      name: data
      annotations:
        volume.beta.kubernetes.io/storage-class: managed-standard
    spec:
      accessModes: [ "ReadWriteOnce" ]
      resources:
        requests:
          storage: 5Gi