$ whoami

Lorenzo Fontana

Software Engineer / DevOps at Facile.it

https://github.com/fntlnz

https://twitter.com/fntlnz

http://engineering.facile.it

What is Ansible

Flexible agentless IT Automation tool that let's you automate everything in all your systems

Batteries included

Agentless

No remote agents needed, Ansible delivers all modules to remote systems and execute tasks as needed and clean up themeselves when complete.

Automate everything

• Provisioning
• Configuration management
• Application deployment
• Intra-service orchestration

Batteries included

• Thousands of modules
• Thousands of roles
• Well written and extensive documentation
• Support

Why Ansible

• Idempotent
• I don't need servers to manage my servers
• Leverages existing auth
• Only python needed
• No programming skills required
• Easy to adopt
• Extensible via modules
• Everything is a YAML file

Tasks

What does this do?

- name: Install gcc
  dnf: name=gcc state=latest

- name: Install cmake
  dnf: name=cmake state=latest
                        

Tasks combine an action (a module and its arguments) with a name, and optionally some other keywords

Yep, dnf is a module

Using a loop

- name: Install build dependencies
  dnf: name={{item}} state=latest
  with_items:
    - automake
    - gcc-c++
    - libtool
    - pkgconfig
    - unzip
    - gcc
    - make
    - cmake

with_items is one of those other keywords

Other modules

- name: Clone Neovim repository (nightly)
  git: repo=https://github.com/neovim/neovim.git
       dest=/tmp/neovim-checkout
       version=nightly
       depth=1

- name: make deps
  command: make deps
  args:
    chdir: /tmp/neovim-checkout
                    

Handlers

When something happen, do something

Handlers are tasks that do not run unless they are notified

- name: template configuration file
  template: src=nginx.conf dest=/usr/local/nginx/nginx.conf
  notify:
     - restart nginx
                        

handlers:
    - name: restart nginx
      service: name=nginx state=restarted
                        

Roles

Roles are unit of organization in Ansible. They contains tasks, handlers, templates, variables etc..

• Break up configuration into repeatable chunks
• Clean structure (next slide)
• Share them on Ansible Galaxy
• Reusable and recyclable

How a role looks like

roles/
    nginx/
        tasks/
            main.yml
        handlers/
            main.yml
        templates/
            nginx.conf
            mysite.conf
        files/
            bar.txt
            foo.sh
        vars/
            main.yml
        defaults/
            main.yml
            

Playbooks

A playbooks is a list of plays, a play is a mapping between a set of hosts and the tasks which run on those hosts to define the role that those systems will perform

All in one playbook

---
- hosts: webservers
  vars:
    http_port: 80
  remote_user: root
  tasks:
  - name: ensure nginx is at the latest version
    yum: name=nginx state=latest
  - name: write the nginx config file
    template: src=nginx.conf dest=/usr/local/nginx/nginx.conf
    notify:
    - restart nginx
  - name: ensure nginx is running (and enable it at boot)
    service: name=nginx state=started enabled=yes
  handlers:
    - name: restart nginx
      service: name=nginx state=restarted
                        

Not very reusable/extensible

Playbook using roles

---
- hosts: webservers
  vars:
    http_port: 80
  roles:
   - nginx
   - php-fpm

- hosts: dbservers
  roles:
   - mysql

How to run a playbook?

ansible-playbook myplaybook.yml -vvvv

Ad-hoc command

Do something really quick, but don't want to save for later

Run an aribrary command on all matching hosts

$ ansible dbservers -m command -a "whoami"

db02 | success | rc=0 >>
fntlnz

db01 | success | rc=0 >>
fntlnz

db03 | success | rc=0 >>
fntlnz

Ping all matching hosts

$ ansible dbservers -m ping 
db02 | success >> {
    "changed": false, 
    "ping": "pong"
}

db03 | success >> {
    "changed": false, 
    "ping": "pong"
}

db01 | success >> {
    "changed": false, 
    "ping": "pong"
}