- Added a doc about Links and Container Naming

docs/sources/use/index.rst

@@ -20,3 +20,4 @@ Contents:
    puppet
    host_integration
    working_with_volumes
+   working_with_links_names

docs/sources/use/working_with_links_names.rst

@@ -0,0 +1,98 @@
+:title: Working with Links and Names
+:description: How to create and use links and names
+:keywords: Examples, Usage, links, docker, documentation, examples, names, name, container naming
+
+.. _working_with_links_names:
+
+Working with Links and Names
+============================
+
+From version 0.6.5 you are able to ``name`` a container and ``link`` it to another
+container by referring its name. This will create a relation parent->child where
+the parent container can see all the important information about its child.
+
+.. _run_name:
+
+Container Naming
+----------------
+
+.. versionadded:: v0.6.5
+
+You can now name your container by using ``-name`` flag. If no name is provided,
+Docker will automatically generate a name which can be seen by typing: ``docker ps``.
+
+.. code-block:: bash
+
+    # format is "sudo docker run -name <container_name> <image_name> <command>"
+    $ sudo docker run -name test ubuntu /bin/bash
+
+.. _run_link:
+
+Links: service discovery for docker
+-----------------------------------
+
+.. versionadded:: v0.6.5
+
+Links allow containers to discover and securely communicate with each other by using the
+flag ``-link name:alias``. Inter-container communication can be disabled with the daemon
+flag ``-icc=false``. With this flag set to false, Container A cannot access Container B
+unless explicitly allowed via a link. This is a huge win for securing your containers.
+When two containers are linked together Docker creates a parent child relationship
+between the containers. The parent container will be able to access information via
+env variables of the child such as name, exposed ports, ip, and environment variables.
+
+When linking two containers Docker will use the exposed ports of the container to create
+a secure tunnel for the parent to access. If a database container only exposes port 8080
+then the linked container will only be allowed to access port 8080 and nothing else if
+inter-container communication is set to false.
+
+.. code-block:: bash
+
+    # Example: there is an image called redis-2.6 that exposes the port 6379 and starts redis-server.
+    # Let's name the container as "redis" based on that image and run it as daemon.
+    $ sudo docker run -d -name redis redis-2.6
+
+We can issue all the commands that you would expect using the name "redis"; start, stop,
+attach, using the name for our container. The name also allows us to link other containers
+into this one.
+
+Next, we can start a new web application that has a dependency on Redis and apply a link
+to connect both containers. If you noticed when running our Redis server we did not use
+the -p flag to publish the Redis port to the host system. Redis exposed port 6379 and
+this is all we need to establish a link.
+
+.. code-block:: bash
+
+    # Linking the redis container as a child
+    $ sudo docker run -t -i -link redis:db -name webapp ubuntu bash
+
+When you specified -link redis:db you are telling docker to link the container named redis
+into this new container with the alias db. Environment variables are prefixed with the alias
+so that the parent container can access network and environment information from the containers
+that are linked into it.
+
+If we inspect the environment variables of the second container, we would see all the information
+about the child container.
+
+.. code-block:: bash
+
+    $ sroot@4c01db0b339c:/# env
+
+    HOSTNAME=4c01db0b339c
+    DB_NAME=/webapp/db
+    TERM=xterm
+    DB_PORT=tcp://172.17.0.8:6379
+    DB_PORT_6379_TCP=tcp://172.17.0.8:6379
+    DB_PORT_6379_TCP_PROTO=tcp
+    DB_PORT_6379_TCP_ADDR=172.17.0.8
+    DB_PORT_6379_TCP_PORT=6379
+    PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
+    PWD=/
+    SHLVL=1
+    HOME=/
+    container=lxc
+    _=/usr/bin/env
+    root@4c01db0b339c:/#
+
+Accessing the network information along with the environment of the child container allows
+us to easily connect to the Redis service on the specific IP and port in the environment.