apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: sentinel
spec:
  serviceName: sentinel
  replicas: 3
  selector:
    matchLabels:
      app: sentinel
  template:
    metadata:
      labels:
        app: sentinel
    spec:
      initContainers:
      - name: config
        image: redis:6.0-alpine
        command: [ "sh", "-c" ]
        args:
          - |
            REDIS_PASSWORD=a-very-complex-password-here
            nodes=redis-0.redis.redis.svc.cluster.local,redis-1.redis.redis.svc.cluster.local,redis-2.redis.redis.svc.cluster.local

            for i in ${nodes//,/ }
            do
                echo "finding master at $i"
                MASTER=$(redis-cli --no-auth-warning --raw -h $i -a $REDIS_PASSWORD info replication | awk '{print $1}' | grep master_host: | cut -d ":" -f2)
                if [ "$MASTER" == "" ]; then
                    echo "no master found"
                    MASTER=
                else
                    echo "found $MASTER"
                    break
                fi
            done
            echo "sentinel monitor mymaster $MASTER 6379 2" >> /tmp/master

            echo "port 5000
            $(cat /tmp/master)
            sentinel down-after-milliseconds mymaster 5000
            sentinel failover-timeout mymaster 60000
            sentinel parallel-syncs mymaster 1
            sentinel auth-pass mymaster $REDIS_PASSWORD
            " > /etc/redis/sentinel.conf
            cat /etc/redis/sentinel.conf
        volumeMounts:
        - name: redis-config
          mountPath: /etc/redis/
      containers:
      - name: sentinel
        image: redis:6.0-alpine
        command: ["redis-sentinel"]
        args: ["/etc/redis/sentinel.conf"]
        ports:
        - containerPort: 5000
          name: sentinel
        volumeMounts:
        - name: redis-config
          mountPath: /etc/redis/
        - name: data
          mountPath: /data
      volumes:
      - name: redis-config
        emptyDir: {}
  volumeClaimTemplates:
  - metadata:
      name: data
    spec:
      accessModes: [ "ReadWriteOnce" ]
      storageClassName: "standard"
      resources:
        requests:
          storage: 50Mi
---
apiVersion: v1
kind: Service
metadata:
  name: sentinel
spec:
  clusterIP: None
  ports:
  - port: 5000
    targetPort: 5000
    name: sentinel
  selector:
    app: sentinel