Ansible

wp:Ansible_(software) is an open-source software platform for configuring and managing computers. It combines multi-node software deployment, ad hoc task execution, and configuration management. Written in Python, it is packaged by RedHat. As of July 2016, we're using Ansible 2.2.0

Ansible provides three main commands:

1. ansible-playbook - to execute an Ansible playbook on the specified systems
2. ansible - to execute an individual shell command or Ansible module on the specified systems
3. ansible-vault - (optional) to encrypt or decrypt YAML files that Ansible uses.

Modules

Ansible comes with over 200 modules that you should get familiar with in order to use the system effectively.

Example Commands

Note: control verbosity with -vvvv

1. ansible -c local -i ~/ansible_hosts -m ping all ping all the hosts in the inventory file
2. ansible -m setup wiki.example.com will show you all the ansible 'facts' (aka ansible_variables) about that host.
3. ansible all -m setup -a "filter=ansible_distribution*" use a filter action to see specific variables
4. ansible -m debug -a "var=hostvars['wiki.example.com']" localhost gives you the 'ansible hostvars'
5. ansible-playbook play1.yml play2.yml Run multiple playbooks
6. ansible-playbook -i production webservers.yml --tags ntp --list-tasks confirm what task names would be run if I ran this command and said "just ntp tasks"
7. ansible-playbook --list-tags launch.yml see what tags exist in my playbook (the tasks list shows more detail + the tags)
8. ansible-playbook -i production webservers.yml --limit boston --list-hosts confirm what hostnames might be communicated with if I said "limit to boston"
9. ~/bin/ansible/contrib/inventory/digital_ocean.py --list --pretty --api-token TOKEN_HERE use the DO api to list your droplets (dynamic inventory)
10. ansible-playbook -vvv launch.yml -l wiki.example.com --user=root -e do_name=wiki.example.com --start-at-task='remove empty wiki schema from database if it already exists' start at a particular point in the task list

Variables

You have 3 plays in one playbook. Will play 3 be able to reference facts registered in play 1?

facts, yes, play vars, no

vars associated to the host, persist, vars defined in the play, do not, set_facts, registered vars and gathered facts associate to the host so those do persist for the run

Playbooks

Ansible "Playbooks" use an easy and descriptive language based on YAML.

Targets

Ansible can deploy to virtualization environments and public and private cloud environments including VMWare, OpenStack, AWS, Eucalyptus Cloud, KVM, and CloudStack

Installation

The preferred way to install is to just git clone the source. Having the source makes it easy to upgrade, and it's self-contained, plus best of all you get all the examples and contribs. However, when I ran my first ansible-playbook digitalocean.yml, I got an error message

Traceback (most recent call last):
  File "/usr/local/bin/ansible-playbook", line 44, in <module>
    import ansible.constants as C
ImportError: No module named ansible.constants

Clearly ansible is falling back to the OS installed version. After I ran source ~/bin/ansible/hacking/env-setup, then I was able to run my ansible playbook

Ansible with MediaWiki

https://github.com/Orain I've cloned the 'ansible-playbook'

Ansible with Drupal

• Jeff Geerling (geerlingguy) has his code on github https://github.com/geerlingguy/drupal-vm, and also a website http://www.drupalvm.com/. He's the author of Ansible for DevOps. The only problem I see with his code is that it installs everything from his own 'roles' (individual components) via the sharing site/mechanism called Ansible Galaxy. So, for example, phpMyAdmin comes from https://github.com/geerlingguy/ansible-role-phpmyadmin This is good in that he can make his system work, but it's bad in that you're getting all your bits from him and can't tweak any of it without manually checking each role for the code and instructions behind it so you know what you can set via variables and such. I'd rather see each of these roles contained in the project, community sourced, installed via git.

geerlingguy.firewall
geerlingguy.git
geerlingguy.apache
geerlingguy.memcached
geerlingguy.mysql
geerlingguy.php
geerlingguy.php-pecl
geerlingguy.php-memcached
geerlingguy.php-mysql
geerlingguy.php-xdebug
geerlingguy.php-xhprof
geerlingguy.phpmyadmin
geerlingguy.composer
geerlingguy.drush
geerlingguy.daemonize
geerlingguy.mailhog
geerlingguy.java
geerlingguy.solr

• on Digital Ocean

Ansible in the cloud

Ansible has several core modules for working with various cloud providers. These include

• Amazon
• Digital Ocean http://docs.ansible.com/digital_ocean_module.html
• Linode http://docs.ansible.com/linode_module.html
• LXC

• OpenStack

Ansible on Fedora

The Fedora Project uses Ansible in it's Infrastructure team, and they publish their whole setup https://infrastructure.fedoraproject.org/cgit/ansible.git/tree/README

Ansible Docs

Some of the docs pages I've visited

• https://docs.ansible.com/ansible/playbooks_intro.html
• https://docs.ansible.com/ansible/intro_inventory.html
• http://docs.ansible.com/playbooks_best_practices.html
• http://docs.ansible.com/playbooks_loops.html
• https://docs.ansible.com/ansible/playbooks_conditionals.html
• https://docs.ansible.com/ansible/playbooks_startnstep.html
• https://docs.ansible.com/ansible/playbooks_roles.html#task-include-files-and-encouraging-reuse
• http://docs.ansible.com/YAMLSyntax.html
• https://docs.ansible.com/ansible/become.html
• https://docs.ansible.com/ansible/debug_module.html
• https://docs.ansible.com/ansible/playbooks_debugger.html (strategy:debug)
• https://docs.ansible.com/ansible/playbooks_conditionals.html#sts=The When Statement%C2%B6

Ansible References

• http://tjelvarolsson.com/blog/taking-the-effort-out-of-server-configuration-using-ansible/
• http://tjelvarolsson.com/blog/how-to-create-automated-and-reproducible-work-flows-for-installing-scientific-software/ < with Vagrant
• http://jpmens.net/2012/06/06/configuration-management-with-ansible/
• Jinja - the template engine for Ansible

Choosing which host(s) to operate on https://docs.ansible.com/ansible/intro_patterns.html