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), CentOS (6)
  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   - `williamyeh/ansible:centos6`
  31
  32 - onbuild series:
  33
  34   - `williamyeh/ansible:debian8-onbuild`
  35   - `williamyeh/ansible:debian7-onbuild`
  36   - `williamyeh/ansible:ubuntu14.04-onbuild`
  37   - `williamyeh/ansible:ubuntu12.04-onbuild`
  38   - `williamyeh/ansible:centos6-onbuild`
  39
  40
  41 ## Why yet another Ansible image for Docker?
  42
  43 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?
  44
  45 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:
  46
  47 - *Base OS image* - It provides only `centos:centos7` and `ubuntu:14.04`.  Insufficent for me.
  48
  49 - *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.
  50
  51 Therefore, I built these Docker images on my own.
  52
  53
  54 ## Usage
  55
  56 Used mostly as a *base image* for configuring, with Ansible, other software stack on some specified Linux distribution.
  57
  58 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:
  59
  60 ```ruby
  61 # Vagrantfile
  62
  63 Vagrant.configure(2) do |config|
  64
  65     # ==> Choose a Vagrant box to emulate Linux distribution...
  66     config.vm.box = "ubuntu/trusty64"
  67     #config.vm.box = "hashicorp/precise64"
  68     #config.vm.box = "chef/debian-7.8"
  69     #config.vm.box = "chef/centos-6.6"
  70
  71
  72     # ==> Executing Ansible...
  73     config.vm.provision "ansible" do |ansible|
  74         ansible.playbook = "playbook.yml"
  75     end
  76
  77 end
  78 ```
  79
  80 Virtual machines can emulate a variety of Linux distributions with good quality, at the cost of runtime overhead.
  81
  82
  83 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:
  84
  85
  86 ```dockerfile
  87 # Dockerfile
  88
  89 # ==> Choose a base image to emulate Linux distribution...
  90 FROM williamyeh/ansible:ubuntu14.04
  91 #FROM williamyeh/ansible:ubuntu12.04
  92 #FROM williamyeh/ansible:debian8
  93 #FROM williamyeh/ansible:debian7
  94 #FROM williamyeh/ansible:centos6
  95
  96
  97 # ==> Copying Ansible playbook...
  98 WORKDIR /tmp
  99 COPY  .  /tmp
 100
 101 # ==> Creating inventory file...
 102 RUN echo localhost > inventory
 103
 104 # ==> Executing Ansible...
 105 RUN ansible-playbook -i inventory playbook.yml \
 106       --connection=local --sudo
 107 ```
 108
 109 Or, more simple with `onbuild` series:
 110
 111 ```dockerfile
 112 # Dockerfile
 113
 114 # ==> Choose a base image to emulate Linux distribution...
 115 FROM williamyeh/ansible:ubuntu14.04-onbuild
 116 #FROM williamyeh/ansible:ubuntu12.04-onbuild
 117 #FROM williamyeh/ansible:debian8-onbuild
 118 #FROM williamyeh/ansible:debian7-onbuild
 119 #FROM williamyeh/ansible:centos6-onbuild
 120
 121
 122 # ==> Specify playbook filename;   default = "playbook.yml"
 123 #ENV PLAYBOOK   playbook.yml
 124
 125 # ==> Specify inventory filename;  default = "/etc/ansible/hosts"
 126 #ENV INVENTORY  inventory.ini
 127
 128 # ==> Executing Ansible...
 129 RUN ansible-playbook-wrapper
 130 ```
 131
 132
 133
 134 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!
 135
 136 If better OS emulation (virtualization) isn't required, the Docker approach (containerization) should give you a more efficient Ansible experience.
 137
 138
 139
 140 ## License
 141
 142 Author: William Yeh <william.pjyeh@gmail.com>
 143
 144 Licensed under the Apache License V2.0. See the [LICENSE file](LICENSE) for details.