README.md

   1 Docker-Ansible base images
   2 ===================
   3
   4 [![Circle CI](https://circleci.com/gh/William-Yeh/docker-ansible.svg?style=shield)](https://circleci.com/gh/William-Yeh/docker-ansible) [![Build Status](https://travis-ci.org/William-Yeh/docker-ansible.svg?branch=master)](https://travis-ci.org/William-Yeh/docker-ansible)
   5
   6
   7 ## Summary
   8
   9 Repository name in Docker Hub: **[williamyeh/ansible](https://registry.hub.docker.com/u/williamyeh/ansible/)**
  10
  11 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.
  12
  13
  14
  15 ## Configuration
  16
  17 These are Docker images for [Ansible](https://github.com/ansible/ansible) software, installed in a selected Linux distributions.
  18
  19 - OS: Debian (jessie, wheezy), Ubuntu (trusty, precise), CentOS (7, 6)
  20
  21 - Ansible: usually the latest version.
  22
  23
  24 ## Images and tags
  25
  26 - normal series:
  27
  28   - `williamyeh/ansible:debian8`
  29   - `williamyeh/ansible:debian7`
  30   - `williamyeh/ansible:ubuntu14.04`
  31   - `williamyeh/ansible:ubuntu12.04`
  32   - `williamyeh/ansible:centos7`
  33   - `williamyeh/ansible:centos6`
  34
  35 - onbuild series:
  36
  37   - `williamyeh/ansible:debian8-onbuild`
  38   - `williamyeh/ansible:debian7-onbuild`
  39   - `williamyeh/ansible:ubuntu14.04-onbuild`
  40   - `williamyeh/ansible:ubuntu12.04-onbuild`
  41   - `williamyeh/ansible:centos7-onbuild`
  42   - `williamyeh/ansible:centos6-onbuild`
  43
  44
  45 ## For the impatient
  46
  47 Here comes a simplest working example for the impatient.
  48
  49 First, choose a base image you'd like to begin with. For example, `williamyeh/ansible:ubuntu14.04-onbuild`.
  50
  51 Second, put the following `Dockerfile` along with your playbook directory:
  52
  53 ```
  54 FROM williamyeh/ansible:ubuntu14.04-onbuild
  55
  56 # ==> Specify requirements filename;  default = "requirements.yml"
  57 #ENV REQUIREMENTS  requirements.yml
  58
  59 # ==> Specify playbook filename;      default = "playbook.yml"
  60 #ENV PLAYBOOK      playbook.yml
  61
  62 # ==> Specify inventory filename;     default = "/etc/ansible/hosts"
  63 #ENV INVENTORY     inventory.ini
  64
  65 # ==> Executing Ansible...
  66 RUN ansible-playbook-wrapper
  67 ```
  68
  69 Third, `docker build .`
  70
  71 Done!
  72
  73 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 [CircleCI](https://circleci.com/)'s and [Travis CI](https://travis-ci.org/)’s Ubuntu 12.04 worker instances.
  74
  75
  76
  77
  78 ## Why yet another Ansible image for Docker?
  79
  80 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?
  81
  82 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:
  83
  84 - *Base OS image* - It provides only `centos:centos7` and `ubuntu:14.04`.  Insufficent for me.
  85
  86 - *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.
  87
  88 Therefore, I built these Docker images on my own.
  89
  90 **NOTE:** [`ansible/ansible-docker-base`](https://github.com/ansible/ansible-docker-base) announced in September 2015: “Ansible no longer maintains images in Dockerhub directly.”
  91
  92 ### Comparison: image size
  93
  94 ```
  95 REPOSITORY                    TAG                   VIRTUAL SIZE
  96 ---------------------------   -------------------   ------------
  97 ansible/centos7-ansible       stable                367.5 MB
  98 ansible/ubuntu14.04-ansible   stable                286.6 MB
  99
 100 williamyeh/ansible            centos6-onbuild       264.2 MB
 101 williamyeh/ansible            centos7-onbuild       275.3 MB
 102 williamyeh/ansible            debian7-onbuild       134.4 MB
 103 williamyeh/ansible            debian8-onbuild       178.3 MB
 104 williamyeh/ansible            ubuntu12.04-onbuild   181.9 MB
 105 williamyeh/ansible            ubuntu14.04-onbuild   238.3 MB
 106 ```
 107
 108
 109 ## Usage
 110
 111 Used mostly as a *base image* for configuring, with Ansible, other software stack on some specified Linux distribution.
 112
 113 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:
 114
 115 ```ruby
 116 # Vagrantfile
 117
 118 Vagrant.configure(2) do |config|
 119
 120     # ==> Choose a Vagrant box to emulate Linux distribution...
 121     config.vm.box = "ubuntu/trusty64"
 122     #config.vm.box = "hashicorp/precise64"
 123     #config.vm.box = "chef/debian-7.8"
 124     #config.vm.box = "chef/centos-7.0"
 125     #config.vm.box = "chef/centos-6.6"
 126
 127
 128     # ==> Executing Ansible...
 129     config.vm.provision "ansible" do |ansible|
 130         ansible.playbook = "playbook.yml"
 131     end
 132
 133 end
 134 ```
 135
 136 Virtual machines can emulate a variety of Linux distributions with good quality, at the cost of runtime overhead.
 137
 138
 139 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:
 140
 141
 142 ```dockerfile
 143 # Dockerfile
 144
 145 # ==> Choose a base image to emulate Linux distribution...
 146 FROM williamyeh/ansible:ubuntu14.04
 147 #FROM williamyeh/ansible:ubuntu12.04
 148 #FROM williamyeh/ansible:debian8
 149 #FROM williamyeh/ansible:debian7
 150 #FROM williamyeh/ansible:centos7
 151 #FROM williamyeh/ansible:centos6
 152
 153
 154 # ==> Copying Ansible playbook...
 155 WORKDIR /tmp
 156 COPY  .  /tmp
 157
 158 # ==> Creating inventory file...
 159 RUN echo localhost > inventory
 160
 161 # ==> Executing Ansible...
 162 RUN ansible-playbook -i inventory playbook.yml \
 163       --connection=local --sudo
 164 ```
 165
 166 Or, more simple with `onbuild` series:
 167
 168 ```dockerfile
 169 # Dockerfile
 170
 171 # ==> Choose a base image to emulate Linux distribution...
 172 FROM williamyeh/ansible:ubuntu14.04-onbuild
 173 #FROM williamyeh/ansible:ubuntu12.04-onbuild
 174 #FROM williamyeh/ansible:debian8-onbuild
 175 #FROM williamyeh/ansible:debian7-onbuild
 176 #FROM williamyeh/ansible:centos7-onbuild
 177 #FROM williamyeh/ansible:centos6-onbuild
 178
 179
 180 # ==> Specify requirements filename;  default = "requirements.yml"
 181 #ENV REQUIREMENTS  requirements.yml
 182
 183 # ==> Specify playbook filename;      default = "playbook.yml"
 184 #ENV PLAYBOOK      playbook.yml
 185
 186 # ==> Specify inventory filename;     default = "/etc/ansible/hosts"
 187 #ENV INVENTORY     inventory.ini
 188
 189 # ==> Executing Ansible...
 190 RUN ansible-playbook-wrapper
 191 ```
 192
 193
 194
 195 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!
 196
 197 If better OS emulation (virtualization) isn't required, the Docker approach (containerization) should give you a more efficient Ansible experience.
 198
 199
 200
 201 ## License
 202
 203 Author: William Yeh <william.pjyeh@gmail.com>
 204
 205 Licensed under the Apache License V2.0. See the [LICENSE file](LICENSE) for details.