README.md

   1 Docker-Ansible base images
   2 ===================
   3
   4
   5 ## Summary
   6
   7 Repository name in Docker Hub: **[williamyeh/ansible](https://registry.hub.docker.com/u/williamyeh/ansible/)**
   8
   9 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.
  10
  11
  12
  13 ## Configuration
  14
  15 These are Docker images for [Ansible](https://github.com/ansible/ansible) software, installed in a selected Linux distributions.
  16
  17 - OS: Debian (jessie, wheezy), Ubuntu (trusty, precise).
  18
  19 - Ansible: usually the latest version.
  20
  21
  22 ## Images and tags
  23
  24 - normal series:
  25
  26   - `williamyeh/ansible:debian8`
  27   - `williamyeh/ansible:debian7`
  28   - `williamyeh/ansible:ubuntu14.04`
  29   - `williamyeh/ansible:ubuntu12.04`
  30
  31 - onbuild series:
  32
  33   - `williamyeh/ansible:debian8-onbuild`
  34   - `williamyeh/ansible:debian7-onbuild`
  35   - `williamyeh/ansible:ubuntu14.04-onbuild`
  36   - `williamyeh/ansible:ubuntu12.04-onbuild`
  37
  38
  39 ## Why yet another Ansible image for Docker?
  40
  41 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?
  42
  43 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:
  44
  45 - *Base OS image* - It provides only `centos:centos7` and `ubuntu:14.04`.  Insufficent for me.
  46
  47 - *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.
  48
  49 Therefore, I built these Docker images on my own.
  50
  51
  52 ## Usage
  53
  54 Used mostly as a *base image* for configuring, with Ansible, other software stack on some specified Linux distribution.
  55
  56 Take Debian/Ubuntu for example. To test an Ansible `playbook.yml` against a variety of Linux distributions, we may use [Vagrant](https://www.vagrantup.com/) as follows:
  57
  58 ```ruby
  59 # Vagrantfile
  60
  61 Vagrant.configure(2) do |config|
  62
  63     # ==> Choose a Vagrant box to emulate Linux distribution...
  64     config.vm.box = "ubuntu/trusty64"
  65     #config.vm.box = "hashicorp/precise64"
  66     #config.vm.box = "chef/debian-7.8"
  67
  68     # ==> Executing Ansible...
  69     config.vm.provision "ansible" do |ansible|
  70         ansible.playbook = "playbook.yml"
  71     end
  72
  73 end
  74 ```
  75
  76 Virtual machines can emulate a variety of Linux distributions with good quality, at the cost of runtime overhead.
  77
  78
  79 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:
  80
  81
  82 ```dockerfile
  83 # Dockerfile
  84
  85 # ==> Choose a base image to emulate Linux distribution...
  86 FROM williamyeh/ansible:ubuntu14.04
  87 #FROM williamyeh/ansible:ubuntu12.04
  88 #FROM williamyeh/ansible:debian8
  89 #FROM williamyeh/ansible:debian7
  90
  91
  92 # ==> Copying Ansible playbook...
  93 WORKDIR /tmp
  94 COPY  .  /tmp
  95
  96 # ==> Creating inventory file...
  97 RUN echo localhost > inventory
  98
  99 # ==> Executing Ansible...
 100 RUN ansible-playbook -i inventory playbook.yml \
 101       --connection=local --sudo
 102 ```
 103
 104 Or, more simple with `onbuild` series:
 105
 106 ```dockerfile
 107 # Dockerfile
 108
 109 # ==> Choose a base image to emulate Linux distribution...
 110 FROM williamyeh/ansible:ubuntu14.04-onbuild
 111 #FROM williamyeh/ansible:ubuntu12.04-onbuild
 112 #FROM williamyeh/ansible:debian8-onbuild
 113 #FROM williamyeh/ansible:debian7-onbuild
 114
 115
 116 # ==> Specify playbook filename;   default = "playbook.yml"
 117 #ENV PLAYBOOK   playbook.yml
 118
 119 # ==> Specify inventory filename;  default = "/etc/ansible/hosts"
 120 #ENV INVENTORY  inventory.ini
 121
 122 # ==> Executing Ansible...
 123 RUN ansible-playbook-wrapper
 124 ```
 125
 126
 127
 128 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!
 129
 130 If better OS emulation (virtualization) isn't required, the Docker approach (containerization) should give you a more efficient Ansible experience.
 131
 132
 133
 134 ## License
 135
 136 Author: William Yeh <william.pjyeh@gmail.com>
 137
 138 Licensed under the Apache License V2.0. See the [LICENSE file](LICENSE) for details.