linuxexpert-practice-labs/labs/ex294/7-1-common-modules/README.md

EX294 7.1: Commonly used modules

Set up a web server with the core modules, make a command task run only once, and read a package's version from the package facts.

Before you start

This VM is the control node. The lab creates the user greg (password Lab-Pass-1) with an SSH key, and installs ansible-core. Work as greg, in /home/greg/ansible: its ansible.cfg reads the inventory inventory (group nodes), logs in as devops and becomes root. No collections are installed beyond ansible-core's own.

The managed nodes node1 (10.99.1.11) and node2 (10.99.1.12) are AlmaLinux 10 containers reached over SSH by name. On each, devops has greg's key and passwordless sudo. node1 runs firewalld, which lets in only SSH. For a root shell on a node, sudo podman exec -it node1 bash.

Tasks

1. Write /home/greg/ansible/web.yml, which installs, starts and enables httpd on node1, deploys its home page /var/www/html/index.html, and opens node1's firewall for it (firewalld keeps running). Then curl http://node1/ on the control node prints the page, and a second run of web.yml reports changed=0.
2. Write /home/greg/ansible/dd.yml, whose command task creates /root/swapfile (16 MiB of zeros) on every node with dd, and make it run only once: a second run of dd.yml reports ok for it, not changed.
3. Write /home/greg/ansible/sshver.yml, which prints the installed version of openssh-server on every node without running rpm.

Hints

• ansible.builtin.dnf, copy, service; ansible.posix.firewalld needs ansible-galaxy collection install ansible.posix, with permanent: true and immediate: true.
• creates: makes a command skip once its file exists.
• ansible.builtin.package_facts, then debug with ansible_facts['packages']['openssh-server'][0]['version'].