Dockerizing a Riak service

Dockerizing a Riak service

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:

$ touch Dockerfile

Next, define the parent image you want to use to build your image on top of. We’ll use Ubuntu (tag: trusty), which is available on Docker Hub:

# Riak
#
# VERSION       0.1.1

# Use the Ubuntu base image provided by dotCloud
FROM ubuntu:trusty
MAINTAINER Hector Castro hector@basho.com

After that, we install the curl which is used to download the repository setup script and we download the setup script and run it.

# Install Riak repository before we do apt-get update, so that update happens
# in a single step
RUN apt-get install -q -y curl && \
    curl -fsSL https://packagecloud.io/install/repositories/basho/riak/script.deb | sudo bash

Then we install and setup a few dependencies:

• supervisor is used manage the Riak processes
• riak=2.0.5-1 is the Riak package coded to version 2.0.5

# Install and setup project dependencies
RUN apt-get update && \
    apt-get install -y supervisor riak=2.0.5-1

RUN mkdir -p /var/log/supervisor

RUN locale-gen en_US en_US.UTF-8

COPY supervisord.conf /etc/supervisor/conf.d/supervisord.conf

After that, we modify Riak’s configuration:

# Configure Riak to accept connections from any host
RUN sed -i "s|listener.http.internal = 127.0.0.1:8098|listener.http.internal = 0.0.0.0:8098|" /etc/riak/riak.conf
RUN sed -i "s|listener.protobuf.internal = 127.0.0.1:8087|listener.protobuf.internal = 0.0.0.0:8087|" /etc/riak/riak.conf

Then, we expose the Riak Protocol Buffers and HTTP interfaces:

# Expose Riak Protocol Buffers and HTTP interfaces
EXPOSE 8087 8098

Finally, run supervisord so that Riak is started:

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:

touch supervisord.conf

Populate it with the following program definitions:

[supervisord]
nodaemon=true

[program:riak]
command=bash -c "/usr/sbin/riak console"
numprocs=1
autostart=true
autorestart=true
user=riak
environment=HOME="/var/lib/riak"
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:

$ docker build -t "<yourname>/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.