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), Alpine (3).
  20
  21 - Ansible: usually the latest version (I didn't pin any specific 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   - `williamyeh/ansible:alpine3`
  35
  36 - Onbuild series (*recommended for common cases*):
  37
  38   - `williamyeh/ansible:debian8-onbuild`
  39   - `williamyeh/ansible:debian7-onbuild`
  40   - `williamyeh/ansible:ubuntu14.04-onbuild`
  41   - `williamyeh/ansible:ubuntu12.04-onbuild`
  42   - `williamyeh/ansible:centos7-onbuild`
  43   - `williamyeh/ansible:centos6-onbuild`
  44   - `williamyeh/ansible:alpine3-onbuild`
  45
  46
  47 ## For the impatient
  48
  49 Here comes a simplest working example for the impatient.
  50
  51 First, choose a base image you'd like to begin with. For example, `williamyeh/ansible:ubuntu14.04-onbuild`.
  52
  53 Second, put the following `Dockerfile` along with your playbook directory:
  54
  55 ```
  56 FROM williamyeh/ansible:ubuntu14.04-onbuild
  57
  58 # ==> Specify requirements filename;  default = "requirements.yml"
  59 #ENV REQUIREMENTS  requirements.yml
  60
  61 # ==> Specify playbook filename;      default = "playbook.yml"
  62 #ENV PLAYBOOK      playbook.yml
  63
  64 # ==> Specify inventory filename;     default = "/etc/ansible/hosts"
  65 #ENV INVENTORY     inventory.ini
  66
  67 # ==> Executing Ansible (with a simple wrapper)...
  68 RUN ansible-playbook-wrapper
  69 ```
  70
  71 Third, `docker build .`
  72
  73 Done!
  74
  75 For more advanced usage, the role in Ansible Galaxy [`williamyeh/nginx`](https://galaxy.ansible.com/list#/roles/2245) demonstrates how to perform a simple smoke test (*configuration needs test, too!*) on a variety of (*containerized*) Linux distributions via [CircleCI](https://circleci.com/)'s Ubuntu 12.04 and [Travis CI](https://travis-ci.org/)’s Ubuntu 14.04 worker instances.
  76
  77
  78
  79
  80 ## Why yet another Ansible image for Docker?
  81
  82 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?
  83
  84 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:
  85
  86 - *Base OS image* - It provides only `centos:centos7` and `ubuntu:14.04`.  Insufficent for me.
  87
  88 - *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.
  89
  90 Therefore, I built these Docker images on my own.
  91
  92 **NOTE:** [`ansible/ansible-docker-base`](https://github.com/ansible/ansible-docker-base) announced in September 2015: “Ansible no longer maintains images in Dockerhub directly.”
  93
  94 ### Comparison: image size
  95
  96 ```
  97 REPOSITORY                    TAG                   VIRTUAL SIZE
  98 ---------------------------   -------------------   ------------
  99 ansible/centos7-ansible       stable                367.5 MB
 100 ansible/ubuntu14.04-ansible   stable                286.6 MB
 101
 102 williamyeh/ansible            alpine3-onbuild        66.4 MB
 103 williamyeh/ansible            centos6-onbuild       264.2 MB
 104 williamyeh/ansible            centos7-onbuild       275.3 MB
 105 williamyeh/ansible            debian7-onbuild       134.4 MB
 106 williamyeh/ansible            debian8-onbuild       178.3 MB
 107 williamyeh/ansible            ubuntu12.04-onbuild   181.9 MB
 108 williamyeh/ansible            ubuntu14.04-onbuild   238.3 MB
 109 ```
 110
 111
 112 ## Usage
 113
 114 Used mostly as a *base image* for configuring other software stack on some specified Linux distribution(s).
 115
 116 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:
 117
 118 ```ruby
 119 # Vagrantfile
 120
 121 Vagrant.configure(2) do |config|
 122
 123     # ==> Choose a Vagrant box to emulate Linux distribution...
 124     config.vm.box = "ubuntu/trusty64"
 125     #config.vm.box = "ubuntu/precise64"
 126     #config.vm.box = "debian/jessie64"
 127     #config.vm.box = "debian/wheezy64"
 128     #config.vm.box = "bento/centos-7.1"
 129     #config.vm.box = "bento/centos-6.7"
 130     #config.vm.box = "maier/alpine-3.1.3-x86_64"
 131
 132
 133     # ==> Executing Ansible...
 134     config.vm.provision "ansible" do |ansible|
 135         ansible.playbook = "playbook.yml"
 136     end
 137
 138 end
 139 ```
 140
 141 Virtual machines can emulate a variety of Linux distributions with good quality, at the cost of runtime overhead.
 142
 143
 144 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:
 145
 146
 147 ```dockerfile
 148 # Dockerfile
 149
 150 # ==> Choose a base image to emulate Linux distribution...
 151 FROM williamyeh/ansible:ubuntu14.04
 152 #FROM williamyeh/ansible:ubuntu12.04
 153 #FROM williamyeh/ansible:debian8
 154 #FROM williamyeh/ansible:debian7
 155 #FROM williamyeh/ansible:centos7
 156 #FROM williamyeh/ansible:centos6
 157 #FROM williamyeh/ansible:alpine3
 158
 159
 160 # ==> Copying Ansible playbook...
 161 WORKDIR /tmp
 162 COPY  .  /tmp
 163
 164 # ==> Creating inventory file...
 165 RUN echo localhost > inventory
 166
 167 # ==> Executing Ansible...
 168 RUN ansible-playbook -i inventory playbook.yml \
 169       --connection=local --sudo
 170 ```
 171
 172 You may also work with `onbuild` series, which take care of many routine steps for you:
 173
 174 ```dockerfile
 175 # Dockerfile
 176
 177 # ==> Choose a base image to emulate Linux distribution...
 178 FROM williamyeh/ansible:ubuntu14.04-onbuild
 179 #FROM williamyeh/ansible:ubuntu12.04-onbuild
 180 #FROM williamyeh/ansible:debian8-onbuild
 181 #FROM williamyeh/ansible:debian7-onbuild
 182 #FROM williamyeh/ansible:centos7-onbuild
 183 #FROM williamyeh/ansible:centos6-onbuild
 184 #FROM williamyeh/ansible:alpine3-onbuild
 185
 186
 187 # ==> Specify requirements filename;  default = "requirements.yml"
 188 #ENV REQUIREMENTS  requirements.yml
 189
 190 # ==> Specify playbook filename;      default = "playbook.yml"
 191 #ENV PLAYBOOK      playbook.yml
 192
 193 # ==> Specify inventory filename;     default = "/etc/ansible/hosts"
 194 #ENV INVENTORY     inventory.ini
 195
 196 # ==> Executing Ansible (with a simple wrapper)...
 197 RUN ansible-playbook-wrapper
 198 ```
 199
 200
 201
 202 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!
 203
 204 If better OS emulation (virtualization) isn't required, the Docker approach (containerization) should give you a more efficient Ansible experience.
 205
 206
 207
 208 ## License
 209
 210 Author: William Yeh <william.pjyeh@gmail.com>
 211
 212 Licensed under the Apache License V2.0. See the [LICENSE file](LICENSE) for details.