Docker-Ansible base images
===================
[](https://circleci.com/gh/William-Yeh/docker-ansible) [](https://travis-ci.org/William-Yeh/docker-ansible)
## Summary
Repository name in Docker Hub: **[williamyeh/ansible](https://registry.hub.docker.com/u/williamyeh/ansible/)**
This repository contains Dockerized [Ansible](https://github.com/ansible/ansible), published to the public [Docker Hub](https://registry.hub.docker.com/) via **automated build** mechanism.
## Configuration
These are Docker images for [Ansible](https://github.com/ansible/ansible) software, installed in a selected Linux distributions.
- OS: Debian (jessie, wheezy), Ubuntu (trusty, precise), CentOS (7, 6)
- Ansible: usually the latest version.
## Images and tags
- normal series:
- `williamyeh/ansible:debian8`
- `williamyeh/ansible:debian7`
- `williamyeh/ansible:ubuntu14.04`
- `williamyeh/ansible:ubuntu12.04`
- `williamyeh/ansible:centos7`
- `williamyeh/ansible:centos6`
- onbuild series:
- `williamyeh/ansible:debian8-onbuild`
- `williamyeh/ansible:debian7-onbuild`
- `williamyeh/ansible:ubuntu14.04-onbuild`
- `williamyeh/ansible:ubuntu12.04-onbuild`
- `williamyeh/ansible:centos7-onbuild`
- `williamyeh/ansible:centos6-onbuild`
## For the impatient
Here comes a simplest working example for the impatient.
First, choose a base image you'd like to begin with. For example, `williamyeh/ansible:ubuntu14.04-onbuild`.
Second, put the following `Dockerfile` along with your playbook directory:
```
FROM williamyeh/ansible:ubuntu14.04-onbuild
# ==> Specify playbook filename; default = "playbook.yml"
#ENV PLAYBOOK playbook.yml
# ==> Specify inventory filename; default = "/etc/ansible/hosts"
#ENV INVENTORY inventory.ini
# ==> Executing Ansible...
RUN ansible-playbook-wrapper
```
Third, `docker build .`
Done!
For more advanced usage, the role in Ansible Galaxy [`williamyeh/nginx`](https://galaxy.ansible.com/list#/roles/2245) also demonstrates how to do a simple integration test for a variety of Linux distributions on [Travis CI](https://travis-ci.org/)’s Ubuntu 12.04 worker instances.
## Why yet another Ansible image for Docker?
There has been quite a few Ansible images for Docker (e.g., [search](https://registry.hub.docker.com/search?q=ansible) in the Docker Hub), so why reinvent the wheel?
In the beginning I used the [`ansible/ansible-docker-base`](https://github.com/ansible/ansible-docker-base) created by Ansible Inc. It worked well, but left some room for improvement:
- *Base OS image* - It provides only `centos:centos7` and `ubuntu:14.04`. Insufficent for me.
- *Unnecessary dependencies* - It installed, at the very beginning of its Dockerfile, the `software-properties-common` package, which in turns installed some Python packages. I prefered to incorporate these stuff only when absolutely needed.
Therefore, I built these Docker images on my own.
### Comparison: image size
```
REPOSITORY TAG VIRTUAL SIZE
--------------------------- ------------------- ------------
ansible/centos7-ansible stable 367.5 MB
ansible/ubuntu14.04-ansible stable 286.6 MB
williamyeh/ansible centos6-onbuild 264.2 MB
williamyeh/ansible centos7-onbuild 275.3 MB
williamyeh/ansible debian7-onbuild 134.4 MB
williamyeh/ansible debian8-onbuild 178.3 MB
williamyeh/ansible ubuntu12.04-onbuild 181.9 MB
williamyeh/ansible ubuntu14.04-onbuild 238.3 MB
```
## Usage
Used mostly as a *base image* for configuring, with Ansible, other software stack on some specified Linux distribution.
Take Debian/Ubuntu/CentOS for example. To test an Ansible `playbook.yml` against a variety of Linux distributions, we may use [Vagrant](https://www.vagrantup.com/) as follows:
```ruby
# Vagrantfile
Vagrant.configure(2) do |config|
# ==> Choose a Vagrant box to emulate Linux distribution...
config.vm.box = "ubuntu/trusty64"
#config.vm.box = "hashicorp/precise64"
#config.vm.box = "chef/debian-7.8"
#config.vm.box = "chef/centos-7.0"
#config.vm.box = "chef/centos-6.6"
# ==> Executing Ansible...
config.vm.provision "ansible" do |ansible|
ansible.playbook = "playbook.yml"
end
end
```
Virtual machines can emulate a variety of Linux distributions with good quality, at the cost of runtime overhead.
Docker to be a rescue. Now, with these **williamyeh/ansible** series, we may test an Ansible `playbook.yml` against a variety of Linux distributions as follows:
```dockerfile
# Dockerfile
# ==> Choose a base image to emulate Linux distribution...
FROM williamyeh/ansible:ubuntu14.04
#FROM williamyeh/ansible:ubuntu12.04
#FROM williamyeh/ansible:debian8
#FROM williamyeh/ansible:debian7
#FROM williamyeh/ansible:centos7
#FROM williamyeh/ansible:centos6
# ==> Copying Ansible playbook...
WORKDIR /tmp
COPY . /tmp
# ==> Creating inventory file...
RUN echo localhost > inventory
# ==> Executing Ansible...
RUN ansible-playbook -i inventory playbook.yml \
--connection=local --sudo
```
Or, more simple with `onbuild` series:
```dockerfile
# Dockerfile
# ==> Choose a base image to emulate Linux distribution...
FROM williamyeh/ansible:ubuntu14.04-onbuild
#FROM williamyeh/ansible:ubuntu12.04-onbuild
#FROM williamyeh/ansible:debian8-onbuild
#FROM williamyeh/ansible:debian7-onbuild
#FROM williamyeh/ansible:centos7-onbuild
#FROM williamyeh/ansible:centos6-onbuild
# ==> Specify playbook filename; default = "playbook.yml"
#ENV PLAYBOOK playbook.yml
# ==> Specify inventory filename; default = "/etc/ansible/hosts"
#ENV INVENTORY inventory.ini
# ==> Executing Ansible...
RUN ansible-playbook-wrapper
```
With Docker, we can test any Ansible playbook against any version of any Linux distribution without the help of Vagrant. More lightweight, and more portable across IaaS, PaaS, and even CaaS (Container as a Service) providers!
If better OS emulation (virtualization) isn't required, the Docker approach (containerization) should give you a more efficient Ansible experience.
## License
Author: William Yeh <william.pjyeh@gmail.com>
Licensed under the Apache License V2.0. See the [LICENSE file](LICENSE) for details.
