Understanding Ansible Inventory Files

What is an Inventory?

Ansible inventory is the list of servers, devices, and hosts that Ansible manages. Inventories can be static or dynamic. They may be written in INI or YAML format

Basic Inventory Example

[webservers]
web1.example.com
web2.example.com

[databases]
db1.example.com

Run:

ansible webservers -i hosts -m ping

Inventory with Variables

[webservers]
web1 ansible_host=192.168.1.10
web2 ansible_host=192.168.1.11

[webservers:vars]
ansible_user=ubuntu

YAML Inventory Example

all:
  children:
    web:
      hosts:
        web1:
          ansible_host: 192.168.1.10
        web2:
          ansible_host: 192.168.1.11

Useful Inventory Commands

List inventory:

ansible-inventory -i hosts --list

Visualize hosts:

ansible-inventory -i hosts --graph

Best Practices

• Group servers by function.
• Use group variables.
• Separate production and development inventories.
• Consider dynamic inventory for cloud environments