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
  91 ### Comparison: image size
  92
  93 ```
  94 REPOSITORY                    TAG                   VIRTUAL SIZE
  95 ---------------------------   -------------------   ------------
  96 ansible/centos7-ansible       stable                367.5 MB
  97 ansible/ubuntu14.04-ansible   stable                286.6 MB
  98
  99 williamyeh/ansible            centos6-onbuild       264.2 MB
 100 williamyeh/ansible            centos7-onbuild       275.3 MB
 101 williamyeh/ansible            debian7-onbuild       134.4 MB
 102 williamyeh/ansible            debian8-onbuild       178.3 MB
 103 williamyeh/ansible            ubuntu12.04-onbuild   181.9 MB
 104 williamyeh/ansible            ubuntu14.04-onbuild   238.3 MB
 105 ```
 106
 107
 108 ## Usage
 109
 110 Used mostly as a *base image* for configuring, with Ansible, other software stack on some specified Linux distribution.
 111
 112 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:
 113
 114 ```ruby
 115 # Vagrantfile
 116
 117 Vagrant.configure(2) do |config|
 118
 119     # ==> Choose a Vagrant box to emulate Linux distribution...
 120     config.vm.box = "ubuntu/trusty64"
 121     #config.vm.box = "hashicorp/precise64"
 122     #config.vm.box = "chef/debian-7.8"
 123     #config.vm.box = "chef/centos-7.0"
 124     #config.vm.box = "chef/centos-6.6"
 125
 126
 127     # ==> Executing Ansible...
 128     config.vm.provision "ansible" do |ansible|
 129         ansible.playbook = "playbook.yml"
 130     end
 131
 132 end
 133 ```
 134
 135 Virtual machines can emulate a variety of Linux distributions with good quality, at the cost of runtime overhead.
 136
 137
 138 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:
 139
 140
 141 ```dockerfile
 142 # Dockerfile
 143
 144 # ==> Choose a base image to emulate Linux distribution...
 145 FROM williamyeh/ansible:ubuntu14.04
 146 #FROM williamyeh/ansible:ubuntu12.04
 147 #FROM williamyeh/ansible:debian8
 148 #FROM williamyeh/ansible:debian7
 149 #FROM williamyeh/ansible:centos7
 150 #FROM williamyeh/ansible:centos6
 151
 152
 153 # ==> Copying Ansible playbook...
 154 WORKDIR /tmp
 155 COPY  .  /tmp
 156
 157 # ==> Creating inventory file...
 158 RUN echo localhost > inventory
 159
 160 # ==> Executing Ansible...
 161 RUN ansible-playbook -i inventory playbook.yml \
 162       --connection=local --sudo
 163 ```
 164
 165 Or, more simple with `onbuild` series:
 166
 167 ```dockerfile
 168 # Dockerfile
 169
 170 # ==> Choose a base image to emulate Linux distribution...
 171 FROM williamyeh/ansible:ubuntu14.04-onbuild
 172 #FROM williamyeh/ansible:ubuntu12.04-onbuild
 173 #FROM williamyeh/ansible:debian8-onbuild
 174 #FROM williamyeh/ansible:debian7-onbuild
 175 #FROM williamyeh/ansible:centos7-onbuild
 176 #FROM williamyeh/ansible:centos6-onbuild
 177
 178
 179 # ==> Specify requirements filename;  default = "requirements.yml"
 180 #ENV REQUIREMENTS  requirements.yml
 181
 182 # ==> Specify playbook filename;      default = "playbook.yml"
 183 #ENV PLAYBOOK      playbook.yml
 184
 185 # ==> Specify inventory filename;     default = "/etc/ansible/hosts"
 186 #ENV INVENTORY     inventory.ini
 187
 188 # ==> Executing Ansible...
 189 RUN ansible-playbook-wrapper
 190 ```
 191
 192
 193
 194 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!
 195
 196 If better OS emulation (virtualization) isn't required, the Docker approach (containerization) should give you a more efficient Ansible experience.
 197
 198
 199
 200 ## License
 201
 202 Author: William Yeh <william.pjyeh@gmail.com>
 203
 204 Licensed under the Apache License V2.0. See the [LICENSE file](LICENSE) for details.