based on StatefulSet

mongodb-ocp-replica.yml

kind: Template
apiVersion: v1
metadata:
  name: mongodb-ocp-replication
  annotations:
    description: "MongoDB Replication Example (based on StatefulSet). You must have persistent volumes available in your cluster to use this template."
    iconClass: "icon-mongodb"
    tags: "database,mongodb,replication"
parameters:
  - name: MONGODB_USER
    displayName: "MongoDB Connection Username"
    description: "Username for MongoDB user that will be used for accessing the database."
    generate: expression
    from: "[a-zA-Z0-9]{3}"
    required: true

  - name: MONGODB_PASSWORD
    displayName: "MongoDB Connection Password"
    description: "Password for the MongoDB connection user."
    generate: expression
    from: "[a-zA-Z0-9]{16}"
    required: true

  - name: MONGODB_DATABASE
    displayName: "MongoDB Database Name"
    description: "Name of the MongoDB database accessed."
    value: "${DB_NAME}"
    required: true

  - name: MONGODB_ADMIN_PASSWORD
    displayName: "MongoDB Admin Password"
    description: "Password for the database admin user."
    generate: expression
    from: "[a-zA-Z0-9]{16}"
    required: true

  - name: MONGODB_REPLICA_NAME
    displayName: "Replica Set Name"
    description: "The name of the replica set."
    value: rs0
    required: true

  - name: MONGODB_KEYFILE_VALUE
    displayName: "Keyfile Content"
    description: "The value of the MongoDB keyfile (https://docs.mongodb.com/manual/core/security-internal-authentication/#internal-auth-keyfile)."
    generate: expression
    from: "[a-zA-Z0-9]{255}"
    required: true

  - name: MONGODB_IMAGE
    displayName: "MongoDB Docker Image"
    description: "A reference to a supported MongoDB Docker image."
    value: "centos/mongodb-32-centos7"
    required: true

  - name: MONGODB_SERVICE_NAME
    displayName: "OpenShift Service Name"
    description: "The name of the OpenShift Service exposed for the database."
    value: mongodb
    required: true

  - name: VOLUME_CAPACITY
    displayName: "Volume Capacity"
    description: "Volume space available for data, e.g. 512Mi, 2Gi."
    value: "1Gi"
    required: true

  - name: MEMORY_LIMIT
    displayName: "Memory Limit"
    description: "Maximum amount of memory the container can use."
    value: "512Mi"

objects:
  # A non-headless service which takes pod readiness into consideration
  - kind: Service
    apiVersion: v1
    metadata:
      name: "${MONGODB_SERVICE_NAME}"
    spec:
      # the list of ports that are exposed by this service
      ports:
        - name: mongodb
          port: 27017
      # will route traffic to pods having labels matching this selector
      selector:
        name: "${MONGODB_SERVICE_NAME}"

  # A headless service to create DNS records
  - kind: Service
    apiVersion: v1
    metadata:
      name: "${MONGODB_SERVICE_NAME}-internal"
      annotations:
        service.alpha.kubernetes.io/tolerate-unready-endpoints: "true"
    spec:
      clusterIP: None
      # the list of ports that are exposed by this service
      ports:
        - name: mongodb
          port: 27017
      # will route traffic to pods having labels matching this selector
      selector:
        name: "${MONGODB_SERVICE_NAME}"

  - kind: StatefulSet
    apiVersion: apps/v1beta1
    metadata:
      name: "${MONGODB_SERVICE_NAME}"
    spec:
      # pets get DNS/hostnames that follow the pattern: ${metadata.name}-NUM.${spec.serviceName}.default.svc.cluster.local
      serviceName: "${MONGODB_SERVICE_NAME}-internal"
      replicas: 3
      # describes the pod that will be created if insufficient replicas are detected
      template:
        metadata:
          # this label will be used for count running pods
          labels:
            name: "${MONGODB_SERVICE_NAME}"
        spec:
          containers:
            - name: mongo-container
              image: "${MONGODB_IMAGE}"
              ports:
                - containerPort: 27017
              args:
                - "run-mongod-pet"
              volumeMounts:
                - name: mongo-data
                  mountPath: "/var/lib/mongodb/data"
              env:
                - name: MONGODB_USER
                  value: "${MONGODB_USER}"
                - name: MONGODB_PASSWORD
                  value: "${MONGODB_PASSWORD}"
                - name: MONGODB_DATABASE
                  value: "${MONGODB_DATABASE}"
                - name: MONGODB_ADMIN_PASSWORD
                  value: "${MONGODB_ADMIN_PASSWORD}"
                - name: MONGODB_REPLICA_NAME
                  value: "${MONGODB_REPLICA_NAME}"
                - name: MONGODB_KEYFILE_VALUE
                  value: "${MONGODB_KEYFILE_VALUE}"
                - name: MONGODB_SERVICE_NAME
                  value: "${MONGODB_SERVICE_NAME}-internal"
              resources:
                limits:
                  memory: "${MEMORY_LIMIT}"
              readinessProbe:
                exec:
                  command:
                    - stat
                    - /tmp/initialized
      volumeClaimTemplates:
        - metadata:
            name: mongo-data
            annotations:
              # Uncomment this if using dynamic volume provisioning.
              # https://docs.openshift.org/latest/install_config/persistent_storage/dynamically_provisioning_pvs.html
              # volume.alpha.kubernetes.io/storage-class: anything
          spec:
            # the volume can be mounted as read-write by a single node
            accessModes: [ ReadWriteOnce ]
            resources:
              requests:
                storage: "${VOLUME_CAPACITY}"