Inventory and ad-hoc commands

Not running Starting usually ~20 s

Step 5 of 5 · summary · 3 min

Summary

The inventory is a list of machines: the name in Ansible, the address ansible_host, the user ansible_user and groups; ansible.cfg in the directory says where the inventory is.
UNREACHABLE! means SSH did not connect and the module never ran: look for the cause in the name, the address, the user and the key.
The ad-hoc command ansible <machines> -m <module> -a '…' does one job on every machine: CHANGED — it changed something, SUCCESS — there was nothing to change, and command always answers CHANGED.
-b runs the module as root through sudo, ansible_connection=local runs it on this machine without SSH.
app1 at the start of the lesson was out of reach because of its inventory line: the machine did not know the address app1.lab.test, and deploy had no key.

Ubuntu 24.04