linuxexpert-practice-labs/labs/ex294/1-3-plays-and-playbooks/README.md

EX294 1.3: Plays and playbooks

Write a playbook with two plays, preview a change with check mode, and find a YAML mistake with a syntax check.

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 inventory, which has node1 in the group webservers and node2 in dbservers, and logs in as ansible. Answers go in /root/lab-answers/<task>, which the lab creates; write them as root.

The managed nodes node1 (10.99.1.11) and node2 (10.99.1.12) 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. They run no firewall. For a root shell on a node, sudo podman exec -it node1 bash.

Tasks

1. Write /home/greg/ansible/site.yml with one play that installs, starts and enables httpd and writes a home page, /var/www/html/index.html, on the webservers, and another play that installs mariadb-server on the dbservers. Run it twice: the second run shows changed=0 for every host, and curl http://node1 from the control node prints the page (open the firewall if one is running).
2. Change the page's text in site.yml and preview the change on node1 only, without making it: --check --diff --limit node1 shows the old and the new line, and curl http://node1 still prints the old text. Leave it that way.
3. Copy site.yml to /home/greg/ansible/broken.yml, break the indentation of one task there, and find the error with --syntax-check. Write the line number it names to /root/lab-answers/3.

Hints

• The plays are a YAML list: each starts with - name: and has hosts:, become: true and tasks:.
• ansible.builtin.dnf, ansible.builtin.copy with content: and dest:, and ansible.builtin.service with state: started and enabled: true.
• ansible-playbook site.yml --check --diff --limit node1.
• ansible-playbook broken.yml --syntax-check; look for "line N" in the error.