##
## Simple ZooKeeper deployment
##

## Define a storage class to ask for SSD
## persistent volumes for ZK
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: ssd
provisioner: kubernetes.io/gce-pd
parameters:
  type: pd-ssd
---

## Define a disruption budget to ensure there are at least
## 1 ZK servers running all the time
apiVersion: policy/v1beta1
kind: PodDisruptionBudget
metadata:
  name: zk-budget
spec:
  selector:
    matchLabels:
      app: zk
  minAvailable: 1
---

## Define a StatefulSet for ZK servers
apiVersion: apps/v1beta1
kind: StatefulSet
metadata:
  name: zk
  labels:
    app: heron
    component: zookeeper
spec:
  serviceName: zookeeper
  replicas: 1
  template:
    metadata:
      labels:
        app: heron
        component: zookeeper

    spec:
      # Make sure multiple pods of ZK don't get scheduled on the
      # same node, unless there are no other available nodes
      affinity:
        podAntiAffinity:
          preferredDuringSchedulingIgnoredDuringExecution:
            - weight: 1
              podAffinityTerm:
                labelSelector:
                  matchExpressions:
                    - key: "app"
                      operator: In
                      values:
                        - zookeeper
                topologyKey: "kubernetes.io/hostname"
      containers:
        - name: zookeeper
          image: heron/heron:latest
          command: ["sh", "-c"]
          args:
            - >
              /opt/zookeeper/scripts/start-zookeeper.sh
          ports:
            - containerPort: 2181
              name: client
            - containerPort: 2888
              name: server
            - containerPort: 3888
              name: leader-election
          env:
            - name: ZOOKEEPER_SERVERS
              value: zk-0
          readinessProbe:
              exec:
                command:
                  - "/opt/zookeeper/scripts/zookeeper-ruok.sh"
              initialDelaySeconds: 5
              timeoutSeconds: 5

          livenessProbe:
              exec:
                command:
                  - "/opt/zookeeper/scripts/zookeeper-ruok.sh"
              initialDelaySeconds: 15
              timeoutSeconds: 5

          volumeMounts:
            - name: datadir
              mountPath: /heron/data

  volumeClaimTemplates:
    - metadata:
        name: datadir
      spec:
        accessModes: [ "ReadWriteOnce" ]
        resources:
          requests:
            storage: 10Gi
        storageClassName: ssd


---

##
## Define the ZooKeeper headless service
##
apiVersion: v1
kind: Service
metadata:
  annotations:
    service.alpha.kubernetes.io/tolerate-unready-endpoints: "true"
  name: zookeeper
  labels:
    app: heron
    component: zookeeper
spec:
  ports:
    - port: 2888
      name: server
    - port: 3888
      name: leader-election
    - port: 2181
      name: client
  clusterIP: None
  selector:
    app: heron
    component: zookeeper