Ansible for Beginners

Contents

1. Why Ansible?
2. Installation and Basic setup
3. Basic Modules
4. Basic of Playbooks

Why Ansible

1. Simple to use
2. Leverages Python
3. Modular
4. Open Source
5. Support multi tier deployment

Ansible: fictional machine capable of instantaneous or superluminal communication.

Installation

1. Using APT (On Ubuntu)
   • $sudo apt-add-repository ppa:ansible/ansible
   • $sudo apt-get update
   • $sudo apt-get install ansible
2. Using YUM/DNF (On RHEL/CentOS/Fedora)
   • $sudo yum install ansible
3. Using PIP (On Mac OS/Other Linux distros)
   • $sudo easy_install pip
   • $sudo pip install ansible

Inventory file

mail.example.com

[webservers]
foo.example.com
bar.example.com

• Default file is /etc/ansible/hosts

SSH-Keys

1. Generate SSH key using $ssh-keygen
2. Make sure you have access to remote system
3. Add your public key (~/.ssh/id_rsa.pub) into remote ~/.ssh/authorized_keys file

Test your setup

1. $ansible all -m ping
2. $ansible all -m ping -u root -k
3. $ansible all -m ping -K
4. $ansible all -m ping -f 10

Modules

1. Libraries that can be executed directly on remote hosts or through Playbooks.
2. User can also write their own modules
3. Two types of modules:
   • Core Modules
   • Extras Modules

Command Modules

• $ansible all -m command -a "ls"
• $ansible all -m command -a "df -h"
• $ansible all -m shell -a "ls"
• $ansible all -m shell -a "ls | grep txt"
• $ansible all -m shell -a "apt-get update"

System Modules:

• $ansible all -m ping
• $ansible all -m setup
• $ansible all -m hostname -a "name=web01"
• $ansible all -m service -a "name=nginx state=started"
• $ansible all -m user -a "name=jsmith generate_ssh_key=yes ssh_key_bits=2048 ssh_key_file=.ssh/id_rsa"

File Modules:

• $ansible all -m copy -a "src=/srv/myfiles/foo.conf dest=/etc/foo.conf"
• $ansible all -m find -a "paths=/tmp patterns=*.old"
• $ansible all -m stat -a "path=/path/to/something checksum_algorithm=sha256"

Source Control Modules:

• $ansible all -m git -a "repo=git://git@github.com/mylogin/hello.git dest=/home/mylogin/hello"
• $ansible all -m git -a "repo=git://foosball.example.org/path/to/repo.git dest=/srv/checkout clone=no update=no"

Packaging Modules:

• $ansible all -m apt -a "name=htop update_cache=yes"
• $ansible all -m apt -a "name=htop state=latest"
• $ansible all -m apt -a "name=htop state=absent"
• $ansible all -m apt -a "upgrade=dist"

Playbooks

Basic Playbook nginx.yml example:

---
- hosts: local
tasks:
  - name: Install Nginx
    apt: pkg=nginx state=installed update_cache=true

To run Playbook : $ansible-playbook -b nginx.yml

Handlers

---
- hosts: local
tasks:
  - name: Install Nginx
    apt: pkg=nginx state=installed update_cache=true
    notify:
      - Start Nginx
handlers:
  - name: Start Nginx
    service: name=nginx state=started

Demo Time

Do it yourself

References

1. http://docs.ansible.com/ansible
2. https://serversforhackers.com/an-ansible-tutorial
3. http://wiki.glitchdata.com/index.php?title=Ansible_Training