Playbooks in Ansible

• Playbooks require you to describe the following important details
  • hosts: where (on which nodes) do you want to run the playbook
  • become: Do you need sudo permissions to execute the automation.
  • tasks: Descriptive way of automating stuff in ansible

---
hosts: all
become: yes
tasks:
  - name: update packages and install git
    apt:
      name: git
      update: yes
      state: present

• Modules: Atomic unit of automation in ansible.
• Refer Here for official documentation.
• Ansible Module will have parameters
  • Some Paramaters are optional and remaining are mandatory
  • Optional Parameters might have default value.
  • In every modules documentation

Example: Write an Ansible Playbook to install git, tree and nano on nodes

• Manual Steps:

# Ubuntu
sudo apt-get update 
sudo apt-get install git -y
sudo apt-get install tree -y
sudo apt-get install nano -y

# Redhat
sudo yum install git -y
sudo yum install tree -y
sudo yum install nano -y

• Ensure the commands are working manually
• Playbook:

---
- hosts: all
  become: yes
  tasks:
    - name: Install git
      apt:
        name: git
        update_cache: yes
        state: present
    - name: Install tree
      apt:
        name: tree
        state: present
    - name: Install nano
      apt:
        name: nano
        state: present
        

• Ansible has a command line for executing playbooks ansible-playbook

ansible-playbook --help
ansible-playbook -i <inventory path> <path to playbook>

• When you run ansible-playbook
  • Playbook recap: with the status of execution on the node. Changed = ansible did some work
• Ansible is trying to maintain state.
• When ansible playbook is failed on a particular node, it will not continue execution by default.
• Whenever executing ansible, ensure you set verbosity while developing playbooks

ansible-playbook -vvv <playbook>
ansible-playbook -vv <playbook>
ansible-playbook -v <playbook>

• Exercise: Write an ansible playbook to install java8, java9 and java 11 on ubuntu machines.