If you read through the redis service example it might answer some of your quest...

If you read through the redis service example it might answer some of your questions:

http://docs.docker.io/en/latest/examples/running_redis_servi...

It shows how a container can be "linked" to another container with an alias, and that alias then causes environment variables within the container to point to the correct IP address and port:

    DB_NAME=/violet_wolf/db
    DB_PORT_6379_TCP_PORT=6379
    DB_PORT=tcp://172.17.0.33:6379
    DB_PORT_6379_TCP=tcp://172.17.0.33:6379
    DB_PORT_6379_TCP_ADDR=172.17.0.33
    DB_PORT_6379_TCP_PROTO=tcp