Ansible concepts

Ansible is a program used to automate setup/updates to several remote machines at once. Plays, variables, tasks, files, etc are divided into various YAML files, and organized into roles. The basic file structure looks like the following:

   site.yml
   role_A.yml
   roles/
      common/
        ...
      role_A/
         files/
         templates/
         tasks/
         handlers/
         vars/
         defaults/
         meta/

The syntax of these yaml files, whether task, playbooks etc, looks roughly like the following:

---
- name: Test Connectivity
  hosts: bsd:linux
  tasks:
     - name:     echo "string" test
       raw:      echo "test"

Each controlled machine is added to a configurable nested ini-style hosts file. Each of these machines is expected to have either an ssh-server (with keys already exchanged), or winrm.

[bsd]
  192.168.1.2:22
  192.168.1.3:22
  [bsd:vars]
  ansible_python_interpreter=/usr/local/bin/python2
[arch]
  192.168.1.4:22
  192.168.1.5:22

Playbooks are run from the command-line. Each task in a play is run on all machines. If a single task fails, the remainder of the tasks in that play are not run on that host.

ansible all -m ping
ansible all -m win_ping
ansible -m setup <hostname>    # get all variables/facts
ansible-playbook myy_play.yml  # run playbook