mongo-statefulset.yaml

apiVersion: apps/v1beta1
kind: StatefulSet
metadata:
  name: mongo
spec:
  serviceName: "mongo" # <--matches the name of mongo headless service
  replicas: 3
  template:
    metadata:
      labels:
        role: mongo
        environment: test
    spec:
      terminationGracePeriodSeconds: 10
      containers:
        - name: mongo
          image: mongo:3.4.20-xenial
          command:
            - mongod
            - "--replSet"
            - rs0
            - "--bind_ip"
            - 0.0.0.0
            - "--smallfiles"
            - "--noprealloc"
          ports:
            - containerPort: 27017
          volumeMounts:
            - name: mongo-persistent-storage
              mountPath: /data/db
        - name: mongo-sidecar
          # This sidecar will configure the MongoDB replica set automatically. 
          # A "sidecar" is a helper container which helps the main container do its work.
          image: cvallance/mongo-k8s-sidecar
          env:
            - name: MONGO_SIDECAR_POD_LABELS
              value: "role=mongo,environment=test"
            - name: KUBERNETES_MONGO_SERVICE_NAME
              value: mongo
  volumeClaimTemplates:
  - metadata:
      name: mongo-persistent-storage
      annotations:
        volume.beta.kubernetes.io/storage-class: "standard" #<-- use minikube storage provisioner to automatically create pvc and pv
    spec:
      accessModes: [ "ReadWriteOnce" ]
      resources:
        requests:
          storage: 2Gi