: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 `_ (tag: ``latest``),
which is available on the `docker index `_:
.. 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
directory 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 "/riak" .
Next steps
++++++++++
Riak is a distributed database. Many production deployments consist of `at
least five nodes `_. See the `docker-riak `_ project details on how to deploy a Riak cluster using Docker and
Pipework.