Add a Docker example for running Riak.

docs/sources/examples/index.rst

@@ -22,3 +22,4 @@ Contents:
    couchdb_data_volumes
    postgresql_service
    mongodb
+   running_riak_service

docs/sources/examples/running_riak_service.rst

@@ -0,0 +1,151 @@
+:title: Running a Riak service
+:description: Build a Docker image with Riak pre-installed
+:keywords: docker, example, package installation, networking, riak
+
+Riak Service
+==============================
+
+.. include:: example_header.inc
+
+The goal of this example is to show you how to build a Docker image with Riak
+pre-installed.
+
+Creating a ``Dockerfile``
++++++++++++++++++++++++++
+
+Create an empty file called ``Dockerfile``:
+
+.. code-block:: bash
+
+    touch Dockerfile
+
+Next, define the parent image you want to use to build your image on top of.
+We’ll use `Ubuntu <https://index.docker.io/_/ubuntu/>`_ (tag: ``latest``),
+which is available on the `docker index <http://index.docker.io>`_:
+
+.. code-block:: bash
+
+    # Riak
+    #
+    # VERSION       0.1.0
+
+    # Use the Ubuntu base image provided by dotCloud
+    FROM ubuntu:latest
+    MAINTAINER Hector Castro hector@basho.com
+
+Next, we update the APT cache and apply any updates:
+
+.. code-block:: bash
+
+    # Update the APT cache
+    RUN sed -i.bak 's/main$/main universe/' /etc/apt/sources.list
+    RUN apt-get update
+    RUN apt-get upgrade -y
+
+After that, we install and setup a few dependencies:
+
+- ``curl`` is used to download Basho's APT repository key
+- ``lsb-release`` helps us derive the Ubuntu release codename
+- ``openssh-server`` allows us to login to containers remotely and join Riak
+  nodes to form a cluster
+- ``supervisor`` is used manage the OpenSSH and Riak processes
+
+.. code-block:: bash
+
+    # Install and setup project dependencies
+    RUN apt-get install -y curl lsb-release supervisor openssh-server
+
+    RUN mkdir -p /var/run/sshd
+    RUN mkdir -p /var/log/supervisor
+
+    RUN locale-gen en_US en_US.UTF-8
+
+    ADD supervisord.conf /etc/supervisor/conf.d/supervisord.conf
+
+    RUN echo 'root:basho' | chpasswd
+
+Next, we add Basho's APT repository:
+
+.. code-block:: bash
+
+    RUN curl -s http://apt.basho.com/gpg/basho.apt.key | apt-key add --
+    RUN echo "deb http://apt.basho.com $(lsb_release -cs) main" > /etc/apt/sources.list.d/basho.list
+    RUN apt-get update
+
+After that, we install Riak and alter a few defaults:
+
+.. code-block:: bash
+
+    # Install Riak and prepare it to run
+    RUN apt-get install -y riak
+    RUN sed -i.bak 's/127.0.0.1/0.0.0.0/' /etc/riak/app.config
+    RUN echo "ulimit -n 4096" >> /etc/default/riak
+
+Almost there. Next, we add a hack to get us by the lack of ``initctl``:
+
+.. code-block:: bash
+
+    # Hack for initctl
+    # See: https://github.com/dotcloud/docker/issues/1024
+    RUN dpkg-divert --local --rename --add /sbin/initctl
+    RUN ln -s /bin/true /sbin/initctl
+
+Then, we expose the Riak Protocol Buffers and HTTP interfaces, along with SSH:
+
+.. code-block:: bash
+
+    # Expose Riak Protocol Buffers and HTTP interfaces, along with SSH
+    EXPOSE 8087 8098 22
+
+Finally, run ``supervisord`` so that Riak and OpenSSH are started:
+
+.. code-block:: bash
+
+    CMD ["/usr/bin/supervisord"]
+
+Create a ``supervisord`` configuration file
++++++++++++++++++++++++++++++++++++++++++++
+
+Create an empty file called ``supervisord.conf``. Make sure it's at the same
+level as your ``Dockerfile``:
+
+.. code-block:: bash
+
+    touch supervisord.conf
+
+Populate it with the following program definitions:
+
+.. code-block:: bash
+
+    [supervisord]
+    nodaemon=true
+
+    [program:sshd]
+    command=/usr/sbin/sshd -D
+    stdout_logfile=/var/log/supervisor/%(program_name)s.log
+    stderr_logfile=/var/log/supervisor/%(program_name)s.log
+    autorestart=true
+
+    [program:riak]
+    command=bash -c ". /etc/default/riak && /usr/sbin/riak console"
+    pidfile=/var/log/riak/riak.pid
+    stdout_logfile=/var/log/supervisor/%(program_name)s.log
+    stderr_logfile=/var/log/supervisor/%(program_name)s.log
+
+Build the Docker image for Riak
++++++++++++++++++++++++++++++++
+
+Now you should be able to build a Docker image for Riak:
+
+.. code-block:: bash
+
+    docker build -t "<yourname>/riak" .
+
+Next steps
+++++++++++
+
+Riak is a distributed database. Many production deployments consist of `at
+least five nodes <http://basho.com/why-your-riak-cluster-should-have-at-least-
+five-nodes/>`_. See the `docker-riak <https://github.com/hectcastro /docker-
+riak>`_ project details on how to deploy a Riak cluster using Docker and
+Pipework.