anchor.diff:  One of the most common types of external services is an external database. To support an external database, an application needs:
   
   1. An endpoint to communicate with.
  -2. A set of credentials and coordinates. Including:
  +2. A set of credentials and coordinates, including:
      a.  A username
      b.  A passphrase
      c.  A database name
  
positive.code:         { "IP": "10.0.0.0" } <3>
        ],
        "ports":  [
          { "port": 80 }
        ]
      }
    ]
  }
  ----
  
  <1> The name of the `Service` instance.
  <2> Traffic to the service will be load-balanced between the supplied
  `Endpoints` if more than one is supplied.
  <3> Endpoints IPs
  https://github.com/kubernetes/kubernetes/blob/master/docs/user-guide/services.md#services-without-selectors[cannot
  be] loopback (127.0.0.0/8), link-local (169.254.0.0/16), or link-local multicast
  (224.0.0.0/24).
  
  ====
  
  === Consuming Credentials in Pods
  
  Now that the service and endpoints are defined, we need to give pods the credentials to use the
  service by setting environment variables in the appropriate containers. In the following
  example, the container receives the following environment variables with credentials for the
  service:
  
  *  `MYSQL_USER`: The username to use with the service.
  *  `MYSQL_PASSWORD`: The passphrase to use with the service.
  *  `MYSQL_DATABASE`: The database name.
  
  ====
  
  
negative.code: ----
  
  <1> Other fields on the `DeploymentConfig` are omitted
  <2> The username to use with the service.
  <3> The passphrase to use with the service.
  <4> The database name.
  
  ====
  
  === External Database Environment Variables
  
  Using an external service in your application is just like using an internal
  service. Your application will be injected with environment variables for the
  service and the additional environment variables with the credentials described
  in the previous step. For example, a MySQL container receives the following
  environment variables:
  
  * `EXTERNAL_MYSQL_SERVICE_SERVICE_HOST`=[replaceable]#<IP_Address>#
  * `EXTERNAL_MYSQL_SERVICE_SERVICE_PORT`=[replaceable]#<Port_Number>#
  