README.md

   1 Docker-Ansible base images
   2 ===================
   3
   4 [![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 playbook filename;   default = "playbook.yml"
  57 #ENV PLAYBOOK   playbook.yml
  58
  59 # ==> Specify inventory filename;  default = "/etc/ansible/hosts"
  60 #ENV INVENTORY  inventory.ini
  61
  62 # ==> Executing Ansible...
  63 RUN ansible-playbook-wrapper
  64 ```
  65
  66 Third, `docker build .`
  67
  68 Done!
  69
  70 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.
  71
  72
  73
  74
  75 ## Why yet another Ansible image for Docker?
  76
  77 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?
  78
  79 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:
  80
  81 - *Base OS image* - It provides only `centos:centos7` and `ubuntu:14.04`.  Insufficent for me.
  82
  83 - *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.
  84
  85 Therefore, I built these Docker images on my own.
  86
  87
  88 ### Comparison: image size
  89
  90 ```
  91 REPOSITORY                    TAG                   VIRTUAL SIZE
  92 ---------------------------   -------------------   ------------
  93 ansible/centos7-ansible       stable                367.5 MB
  94 ansible/ubuntu14.04-ansible   stable                286.6 MB
  95
  96 williamyeh/ansible            centos6-onbuild       264.2 MB
  97 williamyeh/ansible            centos7-onbuild       275.3 MB
  98 williamyeh/ansible            debian7-onbuild       134.4 MB
  99 williamyeh/ansible            debian8-onbuild       178.3 MB
 100 williamyeh/ansible            ubuntu12.04-onbuild   181.9 MB
 101 williamyeh/ansible            ubuntu14.04-onbuild   238.3 MB
 102 ```
 103
 104
 105 ## Usage
 106
 107 Used mostly as a *base image* for configuring, with Ansible, other software stack on some specified Linux distribution.
 108
 109 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:
 110
 111 ```ruby
 112 # Vagrantfile
 113
 114 Vagrant.configure(2) do |config|
 115
 116     # ==> Choose a Vagrant box to emulate Linux distribution...
 117     config.vm.box = "ubuntu/trusty64"
 118     #config.vm.box = "hashicorp/precise64"
 119     #config.vm.box = "chef/debian-7.8"
 120     #config.vm.box = "chef/centos-7.0"
 121     #config.vm.box = "chef/centos-6.6"
 122
 123
 124     # ==> Executing Ansible...
 125     config.vm.provision "ansible" do |ansible|
 126         ansible.playbook = "playbook.yml"
 127     end
 128
 129 end
 130 ```
 131
 132 Virtual machines can emulate a variety of Linux distributions with good quality, at the cost of runtime overhead.
 133
 134
 135 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:
 136
 137
 138 ```dockerfile
 139 # Dockerfile
 140
 141 # ==> Choose a base image to emulate Linux distribution...
 142 FROM williamyeh/ansible:ubuntu14.04
 143 #FROM williamyeh/ansible:ubuntu12.04
 144 #FROM williamyeh/ansible:debian8
 145 #FROM williamyeh/ansible:debian7
 146 #FROM williamyeh/ansible:centos7
 147 #FROM williamyeh/ansible:centos6
 148
 149
 150 # ==> Copying Ansible playbook...
 151 WORKDIR /tmp
 152 COPY  .  /tmp
 153
 154 # ==> Creating inventory file...
 155 RUN echo localhost > inventory
 156
 157 # ==> Executing Ansible...
 158 RUN ansible-playbook -i inventory playbook.yml \
 159       --connection=local --sudo
 160 ```
 161
 162 Or, more simple with `onbuild` series:
 163
 164 ```dockerfile
 165 # Dockerfile
 166
 167 # ==> Choose a base image to emulate Linux distribution...
 168 FROM williamyeh/ansible:ubuntu14.04-onbuild
 169 #FROM williamyeh/ansible:ubuntu12.04-onbuild
 170 #FROM williamyeh/ansible:debian8-onbuild
 171 #FROM williamyeh/ansible:debian7-onbuild
 172 #FROM williamyeh/ansible:centos7-onbuild
 173 #FROM williamyeh/ansible:centos6-onbuild
 174
 175
 176 # ==> Specify playbook filename;   default = "playbook.yml"
 177 #ENV PLAYBOOK   playbook.yml
 178
 179 # ==> Specify inventory filename;  default = "/etc/ansible/hosts"
 180 #ENV INVENTORY  inventory.ini
 181
 182 # ==> Executing Ansible...
 183 RUN ansible-playbook-wrapper
 184 ```
 185
 186
 187
 188 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!
 189
 190 If better OS emulation (virtualization) isn't required, the Docker approach (containerization) should give you a more efficient Ansible experience.
 191
 192
 193
 194 ## License
 195
 196 Author: William Yeh <william.pjyeh@gmail.com>
 197
 198 Licensed under the Apache License V2.0. See the [LICENSE file](LICENSE) for details.