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 most recent *stable* and *experimental* versions (I didn't pin any specific version).
  22
  23
  24 ## Images and tags
  25
  26 ### Stable series (installed from official PyPI repo):
  27
  28 - Normal series:
  29
  30   - `williamyeh/ansible:debian8`
  31   - `williamyeh/ansible:debian7`
  32   - `williamyeh/ansible:ubuntu14.04`
  33   - `williamyeh/ansible:ubuntu12.04`
  34   - `williamyeh/ansible:centos7`
  35   - `williamyeh/ansible:centos6`
  36   - `williamyeh/ansible:alpine3`
  37
  38 - Onbuild series (*recommended for common cases*):
  39
  40   - `williamyeh/ansible:debian8-onbuild`
  41   - `williamyeh/ansible:debian7-onbuild`
  42   - `williamyeh/ansible:ubuntu14.04-onbuild`
  43   - `williamyeh/ansible:ubuntu12.04-onbuild`
  44   - `williamyeh/ansible:centos7-onbuild`
  45   - `williamyeh/ansible:centos6-onbuild`
  46   - `williamyeh/ansible:alpine3-onbuild`
  47
  48 ### Experimental series (building from the git `master` source tree):
  49
  50 - Normal series:
  51
  52   - `williamyeh/ansible:master-debian8`
  53   - `williamyeh/ansible:master-debian7`
  54   - `williamyeh/ansible:master-ubuntu14.04`
  55   - `williamyeh/ansible:master-ubuntu12.04`
  56   - `williamyeh/ansible:master-centos7`
  57   - `williamyeh/ansible:master-centos6`
  58
  59 - Onbuild series (*recommended for common cases*):
  60
  61   - `williamyeh/ansible:master-debian8-onbuild`
  62   - `williamyeh/ansible:master-debian7-onbuild`
  63   - `williamyeh/ansible:master-ubuntu14.04-onbuild`
  64   - `williamyeh/ansible:master-ubuntu12.04-onbuild`
  65   - `williamyeh/ansible:master-centos7-onbuild`
  66   - `williamyeh/ansible:master-centos6-onbuild`
  67
  68
  69
  70 ## For the impatient
  71
  72 Here comes a simplest working example for the impatient.
  73
  74 First, choose a base image you'd like to begin with. For example, `williamyeh/ansible:ubuntu14.04-onbuild`.
  75
  76 Second, put the following `Dockerfile` along with your playbook directory:
  77
  78 ```
  79 FROM williamyeh/ansible:ubuntu14.04-onbuild
  80
  81 # ==> Specify requirements filename;  default = "requirements.yml"
  82 #ENV REQUIREMENTS  requirements.yml
  83
  84 # ==> Specify playbook filename;      default = "playbook.yml"
  85 #ENV PLAYBOOK      playbook.yml
  86
  87 # ==> Specify inventory filename;     default = "/etc/ansible/hosts"
  88 #ENV INVENTORY     inventory.ini
  89
  90 # ==> Executing Ansible (with a simple wrapper)...
  91 RUN ansible-playbook-wrapper
  92 ```
  93
  94 Third, `docker build .`
  95
  96 Done!
  97
  98 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.
  99
 100
 101
 102
 103 ## Why yet another Ansible image for Docker?
 104
 105 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?
 106
 107 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:
 108
 109 - *Base OS image* - It provides only `centos:centos7` and `ubuntu:14.04`.  Insufficent for me.
 110
 111 - *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.
 112
 113 Therefore, I built these Docker images on my own.
 114
 115 **NOTE:** [`ansible/ansible-docker-base`](https://github.com/ansible/ansible-docker-base) announced in September 2015: “Ansible no longer maintains images in Dockerhub directly.”
 116
 117 ### Comparison: image size
 118
 119 ```
 120 REPOSITORY                    TAG                   VIRTUAL SIZE
 121 ---------------------------   -------------------   ------------
 122 ansible/centos7-ansible       stable                367.5 MB
 123 ansible/ubuntu14.04-ansible   stable                286.6 MB
 124
 125 williamyeh/ansible            alpine3-onbuild        66.4 MB
 126 williamyeh/ansible            centos6-onbuild       264.2 MB
 127 williamyeh/ansible            centos7-onbuild       275.3 MB
 128 williamyeh/ansible            debian7-onbuild       134.4 MB
 129 williamyeh/ansible            debian8-onbuild       178.3 MB
 130 williamyeh/ansible            ubuntu12.04-onbuild   181.9 MB
 131 williamyeh/ansible            ubuntu14.04-onbuild   238.3 MB
 132 ```
 133
 134
 135 ## Usage
 136
 137 Used mostly as a *base image* for configuring other software stack on some specified Linux distribution(s).
 138
 139 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:
 140
 141 ```ruby
 142 # Vagrantfile
 143
 144 Vagrant.configure(2) do |config|
 145
 146     # ==> Choose a Vagrant box to emulate Linux distribution...
 147     config.vm.box = "ubuntu/trusty64"
 148     #config.vm.box = "ubuntu/precise64"
 149     #config.vm.box = "debian/jessie64"
 150     #config.vm.box = "debian/wheezy64"
 151     #config.vm.box = "bento/centos-7.1"
 152     #config.vm.box = "bento/centos-6.7"
 153     #config.vm.box = "maier/alpine-3.1.3-x86_64"
 154
 155
 156     # ==> Executing Ansible...
 157     config.vm.provision "ansible" do |ansible|
 158         ansible.playbook = "playbook.yml"
 159     end
 160
 161 end
 162 ```
 163
 164 Virtual machines can emulate a variety of Linux distributions with good quality, at the cost of runtime overhead.
 165
 166
 167 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:
 168
 169
 170 ```dockerfile
 171 # Dockerfile
 172
 173 # ==> Choose a base image to emulate Linux distribution...
 174 FROM williamyeh/ansible:ubuntu14.04
 175 #FROM williamyeh/ansible:ubuntu12.04
 176 #FROM williamyeh/ansible:debian8
 177 #FROM williamyeh/ansible:debian7
 178 #FROM williamyeh/ansible:centos7
 179 #FROM williamyeh/ansible:centos6
 180 #FROM williamyeh/ansible:alpine3
 181
 182
 183 # ==> Copying Ansible playbook...
 184 WORKDIR /tmp
 185 COPY  .  /tmp
 186
 187 # ==> Creating inventory file...
 188 RUN echo localhost > inventory
 189
 190 # ==> Executing Ansible...
 191 RUN ansible-playbook -i inventory playbook.yml \
 192       --connection=local --sudo
 193 ```
 194
 195 You may also work with `onbuild` series, which take care of many routine steps for you:
 196
 197 ```dockerfile
 198 # Dockerfile
 199
 200 # ==> Choose a base image to emulate Linux distribution...
 201 FROM williamyeh/ansible:ubuntu14.04-onbuild
 202 #FROM williamyeh/ansible:ubuntu12.04-onbuild
 203 #FROM williamyeh/ansible:debian8-onbuild
 204 #FROM williamyeh/ansible:debian7-onbuild
 205 #FROM williamyeh/ansible:centos7-onbuild
 206 #FROM williamyeh/ansible:centos6-onbuild
 207 #FROM williamyeh/ansible:alpine3-onbuild
 208
 209
 210 # ==> Specify requirements filename;  default = "requirements.yml"
 211 #ENV REQUIREMENTS  requirements.yml
 212
 213 # ==> Specify playbook filename;      default = "playbook.yml"
 214 #ENV PLAYBOOK      playbook.yml
 215
 216 # ==> Specify inventory filename;     default = "/etc/ansible/hosts"
 217 #ENV INVENTORY     inventory.ini
 218
 219 # ==> Executing Ansible (with a simple wrapper)...
 220 RUN ansible-playbook-wrapper
 221 ```
 222
 223
 224
 225 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!
 226
 227 If better OS emulation (virtualization) isn't required, the Docker approach (containerization) should give you a more efficient Ansible experience.
 228
 229
 230
 231 ## License
 232
 233 Author: William Yeh <william.pjyeh@gmail.com>
 234
 235 Licensed under the Apache License V2.0. See the [LICENSE file](LICENSE) for details.