DevOps Classroom notes 13/Feb/2026

Variables in Ansible

• Refer Here for official docs
• Ansible allows us to use variables which can be changed during execution.
• Variables can have default values
• Ansible allows to set variables from multiple places, ansible has precedence order.
• Where we can set ansible variables

Give me tabular summary of where we can set variables in ansible

• Ansible uses {{ variable_name }} to get the variable value.
• This syntax is inspired for jinja2 templates

Give me simple examples of jinja2 template expressions, i will be using them in ansible

Lets create a simple playbook

• The playbook is

---
- name: learning variables
  hosts: dev
  tasks:
    - name: var1
      ansible.builtin.debug:
        msg: Hello {{ var1  }}
    - name: var2
      ansible.builtin.debug:
        msg: Hello {{ var2 }}

• The inventory is

[dev]
localhost

• Lets execute the playbook without passing any values. The playbook execution fails
• lets execute the playbook by passing variable values using extravars

ansible-playbook -i hosts var_demo.yaml -e var1=sita  -e var2=geeta

• Now lets assign default values if variable is not defined

---
- name: learning variables
  hosts: dev
  tasks:
    - name: var1
      ansible.builtin.debug:
        msg: Hello {{ var1 | default(' ') }}
    - name: var2
      ansible.builtin.debug:
        msg: Hello {{ var2 | default(' ') }}

• using default expression works but defining that everytime is often missed.
• We can define variables in or around inventory files as well
• Inventory has host and group, we can define variable at group level or inventory level
• host level

[dev]
localhost var1=NA  var2=NA

• Playbook

---
- name: learning variables
  hosts: dev
  tasks:
    - name: var1
      ansible.builtin.debug:
        msg: Hello {{ var1  }}
    - name: var2
      ansible.builtin.debug:
        msg: Hello {{ var2 }}

• Group level vars

[dev]
localhost

[dev:vars]
var1=NA  
var2=NA

• If you have many variables to add, directly adding them to inventory is not a good idea

inventory/
├── hosts
├── group_vars/
│   ├── all.yml
│   ├── webservers.yml
│   └── dbservers.yml
└── host_vars/
    ├── web1.yml
    ├── web2.yml
    └── db1.yml

• Next topics
  • Ansible also has special variables list all ansible special variables with its purpose in tabular form
  • facts