Docker - Creating An Alpine Image With Ansible

As I am experimenting with Docker images and finding the right combination which works well for me the majority of the time. I have finally put together a simple Dockerfile which uses Alpine Linux as the base image and installs Ansible. Why Ansible in a Docker image? Because for me it allows me to get around BASH and use a desired state methodology. Now this may not be for everyone but it works really well for me. Especially when I am using this base image to do additional complex configuration either during the image creation or during the spin-up of a container which may require custom provisioning. So, with this all being said you will find the very simple Dockerfile below which will install Ansible for us.

Dockerfile

FROM alpine:3.4

MAINTAINER Larry Smith Jr. <[email protected]>

RUN apk update && \
apk add --no-cache ansible && \
rm -rf /tmp/* && \
rm -rf /var/cache/apk/*

To build your image simply create the Dockerfile above and then build the image:

docker build -t alpine-ansible .

So why Alpine Linux? Because it is small… How small? Let’s compare a few base images.

Ubuntu 14.04

ubuntu 14.04 b1719e1db756 34 hours ago 188 MB

Ubuntu 16.04

ubuntu 16.04 45bc58500fa3 34 hours ago 126.9 MB

Debian Jessie

debian jessie a24c3183e910 33 hours ago 123 MB

Alpine 3.4

alpine 3.4 7d23b3ca3463 28 hours ago 4.799 MB

Now let’s look at what a Ubuntu image looks like with Ansible installed:

mrlesmithjr/ubuntu-ansible latest 69c2195ca7d7 31 hours ago 242.2 MB

As you can see, installing Ansible added about ~120MB to our base image. Now let’s see what an Alpine image looks like with Ansible installed:

mrlesmithjr/alpine-ansible latest 5291ba47263e 26 hours ago 65.01 MB

Wow…We have only increased our Alpine base image by ~60MB… This cuts out almost half of the size of even a Debian or Ubuntu base image.

So there you have it…

Now you can leverage my pre-build Alpine image with Ansible installed in a new Dockerfile to create a new image for another app:

Dockerfile

FROM mrlesmithjr/alpine-ansible

...

Or, even build your own image now.

I will be creating another post in the near future on how to build additional images for apps which will leverage this Alpine image with Ansible.

Enjoy!