Ansible

• ad hoc task execution
• config mgt
• deployment and orchestration
• ssh based, daemonless
• built with python

command line

ansible all -i inventory -u root -m ping -vvv
# inventory, user root, module ping, very verbose
# copies file to server, exec file (with python), report result

ansible all -m apt -a "pkg=dead-parrot state=present"
# idempotent, run multiple times
# success reported along with {"changed": false} (or true)

All Ansible modules are idempotent, so they don’t make changes on a second application when not necessary

Playbook

- hosts: all
  user: root

  tasks:
    - name: install nginx
      apt: pkg=nginx state=latest

    - name: The home page is configured
      copy: src=... dest=/var/share/nginx/www/index.html

A set of Ansible instructions is called a “playbook”, where this contains a hostname, username and tasks in YAML format

• fabric - run commands only over ssh - not designed for idempotency
• salt - have to install daemons, tasks follow dependencies
• puppet, chef - daemon based, DSL