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Merge pull request #2162 from dotcloud/links

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Links and Container Naming
This commit is contained in:
Michael Crosby
2013-10-28 19:24:10 -07:00
parent 76afb6e73d 7e8b2c3836
commit b038b0cd44
58 changed files with 5116 additions and 886 deletions
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docs/sources/api/docker_remote_api_v1.6.rst
+1
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@@ -151,6 +151,7 @@ Create a container
}
:jsonparam config: the container's configuration
:query name: container name to use
:statuscode 201: no error
:statuscode 404: no such container
:statuscode 406: impossible to attach (container not running)
docs/sources/commandline/cli.rst
+72 -7
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@@ -96,8 +96,8 @@ Examples:
.. _cli_build_examples:
Examples
~~~~~~~~
Examples:
~~~~~~~~~
.. code-block:: bash
@@ -430,7 +430,6 @@ Insert file from github
``logs``
--------
::
Usage: docker logs [OPTIONS] CONTAINER
@@ -510,6 +509,29 @@ Insert file from github
Usage: docker rm [OPTIONS] CONTAINER
Remove one or more containers
-link="": Remove the link instead of the actual container
Examples:
~~~~~~~~~
.. code-block:: bash
$ docker rm /redis
/redis
This will remove the container referenced under the link ``/redis``.
.. code-block:: bash
$ docker rm -link /webapp/redis
/webapp/redis
This will remove the underlying link between ``/webapp`` and the ``/redis`` containers removing all
network communication.
.. _cli_rmi:
@@ -533,7 +555,7 @@ Insert file from github
Run a command in a new container
-a=map[]: Attach to stdin, stdout or stderr.
-a=map[]: Attach to stdin, stdout or stderr
-c=0: CPU shares (relative weight)
-cidfile="": Write the container ID to the file
-d=false: Detached mode: Run container in the background, print new container id
@@ -549,14 +571,17 @@ Insert file from github
-u="": Username or UID
-dns=[]: Set custom dns servers for the container
-v=[]: Create a bind mount with: [host-dir]:[container-dir]:[rw|ro]. If "container-dir" is missing, then docker creates a new volume.
-volumes-from="": Mount all volumes from the given container.
-entrypoint="": Overwrite the default entrypoint set by the image.
-volumes-from="": Mount all volumes from the given container
-entrypoint="": Overwrite the default entrypoint set by the image
-w="": Working directory inside the container
-lxc-conf=[]: Add custom lxc options -lxc-conf="lxc.cgroup.cpuset.cpus = 0,1"
-sig-proxy=false: Proxify all received signal to the process (even in non-tty mode)
-expose=[]: Expose a port from the container without publishing it to your host
-link="": Add link to another container (name:alias)
-name="": Assign the specified name to the container. If no name is specific docker will generate a random name
Examples
~~~~~~~~
--------
.. code-block:: bash
@@ -604,6 +629,46 @@ working directory, by changing into the directory to the value
returned by ``pwd``. So this combination executes the command
using the container, but inside the current working directory.
.. code-block:: bash
docker run -p 127.0.0.0::80 ubuntu bash
This the ``-p`` flag now allows you to bind a port to a specific
interface of the host machine. In this example port ``80`` of the
container will have a dynamically allocated port bound to 127.0.0.1
of the host.
.. code-block:: bash
docker run -p 127.0.0.1:80:80 ubuntu bash
This will bind port ``80`` of the container to port ``80`` on 127.0.0.1 of your
host machine.
.. code-block:: bash
docker run -expose 80 ubuntu bash
This will expose port ``80`` of the container for use within a link
without publishing the port to the host system's interfaces.
.. code-block:: bash
docker run -name console -t -i ubuntu bash
This will create and run a new container with the container name
being ``console``.
.. code-block:: bash
docker run -link /redis:redis -name console ubuntu bash
The ``-link`` flag will link the container named ``/redis`` into the
newly created container with the alias ``redis``. The new container
can access the network and environment of the redis container via
environment variables. The ``-name`` flag will assign the name ``console``
to the newly created container.
.. _cli_search:
``search``
docs/sources/examples/index.rst
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@@ -1,6 +1,6 @@
:title: Docker Examples
:description: Examples on how to use Docker
:keywords: docker, hello world, node, nodejs, python, couch, couchdb, redis, ssh, sshd, examples, postgresql
:keywords: docker, hello world, node, nodejs, python, couch, couchdb, redis, ssh, sshd, examples, postgresql, link
.. _example_list:
@@ -24,3 +24,4 @@ to more substantial services like you might find in production.
postgresql_service
mongodb
running_riak_service
linking_into_redis
docs/sources/examples/linking_into_redis.rst
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@@ -0,0 +1,120 @@
:title: Linking to an Redis container
:description: Running redis linked into your web app
:keywords: docker, example, networking, redis, link
.. _linking_redis:
Linking Redis
=============
.. include:: example_header.inc
Building a redis container to link as a child of our web application.
Building the redis container
----------------------------
We will use a pre-build version of redis from the index under
the name ``crosbymichael/redis``. If you are interested in the
Dockerfile that was used to build this container here it is.
.. code-block:: bash
# Build redis from source
# Make sure you have the redis source code checked out in
# the same directory as this Dockerfile
FROM ubuntu
RUN echo "deb http://archive.ubuntu.com/ubuntu precise main universe" > /etc/apt/sources.list
RUN apt-get update
RUN apt-get upgrade -y
RUN apt-get install -y gcc make g++ build-essential libc6-dev tcl
ADD . /redis
RUN (cd /redis && make)
RUN (cd /redis && make test)
RUN mkdir -p /redis-data
VOLUME ["/redis-data"]
EXPOSE 6379
ENTRYPOINT ["/redis/src/redis-server"]
CMD ["--dir", "/redis-data"]
We need to ``EXPOSE`` the default port of 6379 so that our link knows what ports
to connect to our redis container on. If you do not expose any ports for the
image then docker will not be able to establish the link between containers.
Run the redis container
-----------------------
.. code-block:: bash
docker run -d -e PASSWORD=docker -name redis crosbymichael/redis --requirepass=docker
This will run our redis container using the default port of 6379 and using docker
as password to secure our service. By specifying the ``-name`` flag on run
we will assign the name ``redis`` to this container.
We can issue all the commands that you would expect; start, stop, attach, using the name.
The name also allows us to link other containers into this one. If you do not specify a
name on docker run, docker will automatically generate a name for your container.
Linking redis as a child
------------------------
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 service we did not use
the ``-p`` option to publish the redis port to the host system. Redis exposed port 6379
but we did not publish the port. This allows docker to prevent all network traffic to
the redis container except when explicitly specified within a link. This is a big win
for security.
Now lets start our web application with a link into redis.
.. code-block:: bash
docker run -t -i -link /redis:db -name webapp ubuntu bash
root@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
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
PWD=/
DB_ENV_PASSWORD=dockerpass
SHLVL=1
HOME=/
container=lxc
_=/usr/bin/env
root@4c01db0b339c:/#
When we inspect the environment of the linked container we can see a few extra environment
variables have been added. 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 child.
.. code-block:: bash
# The name of the child container
DB_NAME=/webapp/db
# The default protocol, ip, and port of the service running in the container
DB_PORT=tcp://172.17.0.8:6379
# A specific protocol, ip, and port of various services
DB_PORT_6379_TCP=tcp://172.17.0.8:6379
# Get environment variables of the container
DB_ENV_PASSWORD=dockerpass
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 and use the password
specified in the environment.