linuxexpert-practice-labs/labs/ex294/1-1-inventories-and-modules/README.md

EX294 1.1: Inventories, modules and ad hoc commands

Write an inventory with two groups, reach every host with the ping module, install a package with an ad hoc command, and pick hosts with a pattern.

Before you start

This VM is the control node. The lab installs ansible-core and creates the user greg (password Lab-Pass-1), who has an SSH key. Work as greg (su - greg as root), in /home/greg/ansible: its ansible.cfg reads the inventory file inventory, which doesn't exist yet, and logs in as ansible. Answers go in /root/lab-answers/<task>, which the lab creates; write them as root.

The managed nodes node1, node2 and node3 (10.99.1.11 to .13) are AlmaLinux 10 containers with their own users and packages, reached over SSH by name. On each, the user ansible accepts greg's key and may use sudo without a password. For a root shell on a node, sudo podman exec -it node1 bash.

Tasks

1. Write the inventory /home/greg/ansible/inventory with node1 and node2 in the group webservers and node3 in dbservers, and show it as a tree.
2. Run the ping module against every host; each must answer pong.
3. Install the tree package on the webservers with an ad hoc command, then run the same command again: the first run says CHANGED, the second SUCCESS. ansible webservers -a 'rpm -q tree' finds it.
4. List the hosts matched by all:!dbservers without running anything, and write the hosts it shows to /root/lab-answers/4.

Hints

• ansible-inventory -i inventory --graph.
• ansible all -m ansible.builtin.ping.
• ansible webservers -m ansible.builtin.dnf -a 'name=tree state=present' needs -b to become root.
• --list-hosts; quote the pattern so the shell leaves the ! alone. Root can run Ansible from greg's project too: cd /home/greg/ansible && ansible ... >/root/lab-answers/4.