What is an Ansible inventory?

An inventory is the list of managed hosts Ansible operates on, organized into groups. It can hold connection details and variables per host or group. Playbooks target groups or hosts from the inventory using the hosts directive.

INI or YAML — which inventory format should I use?

INI is concise and great for simple static inventories. YAML is more expressive for nested groups and complex variable structures. Both are equivalent in capability; this builder generates either from the same data.

What are group variables and children?

Group variables apply to every host in a group, so you set common values like ansible_user once. Children let a group contain other groups, building a hierarchy — for example a production group whose children are webservers and databases.

What is ansible_host used for?

ansible_host overrides the address Ansible connects to, letting the inventory name be a friendly alias while the actual connection uses an IP or different hostname. Other connection vars include ansible_user, ansible_port, and ansible_ssh_private_key_file.

How do I use the generated inventory?

Save it to a file such as inventory.ini or inventory.yml and pass it with ansible-playbook -i inventory.ini site.yml. You can also set it as the default inventory in ansible.cfg so the flag is not needed.

Ansible Inventory File Builder

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Build a correct Ansible inventory, INI or YAML

The inventory tells Ansible which hosts to manage and how to reach them. Getting the group, variable, and children syntax right by hand is fiddly — especially across the INI and YAML formats. This builder lets you model groups, hosts, variables, and hierarchy once and emit either format cleanly.

How it works

In INI format, hosts are listed under a [group] header, group variables go in a [group:vars] section, and nested groups are declared in [group:children]. Per-host variables follow the host name on the same line as key=value pairs. This is the layout Ansible’s ini inventory plugin parses.

In YAML format, everything nests under the implicit all group: all → children → <group> → hosts/vars/children. Each host becomes a mapping whose values are its connection variables. The builder quotes any YAML scalar that could be misread as a number or boolean, so a value like ansible_port: "2222" stays a string when intended.

Tips and notes

Use ansible_host to keep readable inventory aliases while connecting to real IPs.
Define shared settings such as ansible_user once as a group var rather than repeating them per host.
Build hierarchy with children groups (e.g. a production group whose children are webservers and databases) to target broad or narrow sets in playbooks.
Validate the result with ansible-inventory -i <file> --list to confirm Ansible parses it as you expect.