Chapter 16. Integrating External Services

A set of credentials and coordinates, including:

Create an OpenShift Enterprise service to represent your external database. This is similar to creating an internal service; the difference is in the service’s Selector field.

Internal OpenShift Enterprise services use the Selector field to associate pods with services using labels. The EndpointsController system component synchronizes the endpoints for services that specify selectors with the pods that match the selector. The service proxy and OpenShift Enterprise router load-balance requests to the service amongst the service’s endpoints.

Services that represent an external resource do not require associated pods. Instead, leave the Selector field unset. This represents the external service, making the EndpointsController ignore the service and allows you to specify endpoints manually:

  kind: "Service"
  apiVersion: "v1"
  metadata:
    name: "external-mysql-service"
  spec:
    ports:
      -
        name: "mysql"
        protocol: "TCP"
        port: 3306
        targetPort: 3306
        nodePort: 0
  selector: {} 1

Next, create the required endpoints for the service. This gives the service proxy and router the location to send traffic directed to the service:

  kind: "Endpoints"
  apiVersion: "v1"
  metadata:
    name: "external-mysql-service" 1
  subsets: 2
    -
      addresses:
        -
          ip: "10.0.0.0" 3
      ports:
        -
          port: 3306 4
          name: "mysql"

Now that the service and endpoints are defined, give the appropriate pods access to the credentials to use the service by setting environment variables in the appropriate containers:

  kind: "DeploymentConfig"
  apiVersion: "v1"
  metadata:
    name: "my-app-deployment"
  spec: 1
    strategy:
      type: "Rolling"
      rollingParams:
        updatePeriodSeconds: 1
        intervalSeconds: 1
        timeoutSeconds: 120
    replicas: 2
    selector:
      name: "frontend"
    template:
      metadata:
        labels:
          name: "frontend"
      spec:
        containers:
          -
            name: "helloworld"
            image: "origin-ruby-sample"
            ports:
              -
                containerPort: 3306
                protocol: "TCP"
            env:
              -
                name: "MYSQL_USER"
                value: "${MYSQL_USER}" 2
              -
                name: "MYSQL_PASSWORD"
                value: "${MYSQL_PASSWORD}" 3
              -
                name: "MYSQL_DATABASE"
                value: "${MYSQL_DATABASE}" 4

A set of credentials, such as:

Create an OpenShift Enterprise service to represent the external service. This is similar to creating an internal service; however the difference is in the service’s Selector field.

Internal OpenShift Enterprise services use the Selector field to associate pods with services using labels. A system component called EndpointsController synchronizes the endpoints for services that specify selectors with the pods that match the selector. The service proxy and OpenShift Enterprise router load-balance requests to the service amongst the service’s endpoints.

Services that represents an external resource do not require that pods be associated with it. Instead, leave the Selector field unset. This makes the EndpointsController ignore the service and allows you to specify endpoints manually:

  kind: "Service"
  apiVersion: "v1"
  metadata:
    name: "example-external-service"
  spec:
    ports:
      -
        name: "mysql"
        protocol: "TCP"
        port: 3306
        targetPort: 3306
        nodePort: 0
  selector: {} 1

Next, create endpoints for the service containing the information about where to send traffic directed to the service proxy and the router:

kind: "Endpoints"
apiVersion: "v1"
metadata:
  name: "example-external-service" 1
subsets: 2
- addresses:
  - ip: "10.10.1.1"
  ports:
  - name: "mysql"
    port: 3306