Writing your first playbook

Agenda

What is a playbook?
What are we Automating
What makes up a playbook
Roles and Sharing Automation

What are you automating?

What OS? What kinds of security measures are on the managed node?
Ansible will do what you tell it to.

What is a playbook?

A set of instructions to do something on a remote host(s)

What makes up a playbook?

Header
Tasks
Handlers


---
- hosts: webservers
  vars:
    http_port: 80
    max_clients: 200
  remote_user: root
  tasks:
  - name: ensure apache is at the latest version
    yum:
      name: httpd
      state: latest

Forming a task

Starts with a name
The module and specific arguments
Your variables can be used in arguments

Conditionals

Yes, you can use them in playbooks

Some of the most popular are:

When Statement
Register

When Statement


tasks:
  - name: "shut down Debian flavored systems"
    command: /sbin/shutdown -t now
    when: ansible_facts['os_family'] == "Debian"

Using Loops

Loops can be used to save some typing.
Short handed task writing to automate your keystrokes

Loop Example


- name: add several users
  user:
    name: "{{ item }}"
    state: present
    groups: "wheel"
  loop:
     - testuser1
     - testuser2

Handlers

The quicker restarter, the cleanup crew.
Regardless of how many tasks notify a handler, it will run only ONCE.

What a handler looks like


- name: restart apache
      service:
        name: httpd
        state: restarted

Notifying a handler


- name: write the apache config file
    template:
      src: /srv/httpd.j2
      dest: /etc/httpd.conf
    notify:
    - restart apache

Roles and Sharing Automation

What are roles?
Playbook vs Role

Roles are ways of automatically loading certain vars_files, tasks, and handlers based on a known file structure. Grouping content by roles also allows easy sharing of roles with other users.

Imagine you need to provision a server for a web app and coworker needs a db machine. At the end of the day, both machines are doing different jobs but if you are a part of a large organization, you might have a standard image.

Using roles, you can write a provisioning role that provisions the machine exactly as your organization outlines it and then share that role with a co-worker and it will work exactly the same way.

Playbooks and roles are different, playbooks is the larger picture, provisioning the machine AND installing the app while roles are small bite size chunks of automation. ONLY provisioning the machine or ONLY installing nginx.

Ansible Galaxy

What is it?
How can I use it?
https://galaxy.ansible.com/