linuxexpert-practice-labs/labs/linux-plus/4-1-1-ansible/README.md

Linux+ 4.1.1: Ansible

An inventory, ad hoc commands, and a playbook that installs a package, manages a file and starts a service, run until it changes nothing.

Before you start

The VM needs internet access. This one VM is both the control node and the managed host: Ansible reaches it over SSH at 127.0.0.1. The lab creates user alice (password Lab-Pass-1), who may use sudo with her password, installs at and stops and disables atd. Work as alice for the Ansible tasks (sudo -iu alice is fine). le-lab reset puts /etc/motd back.

Tasks

1. Install Ansible. As alice, set up key-based SSH from alice to [email protected], and write ~/ans/inventory.ini with a group lab that holds 127.0.0.1 with ansible_user=alice. Run the ping and setup modules against lab.
2. Write ~/ans/site.yml, a play for lab that becomes root and installs tree, writes /etc/motd with the content Managed by Ansible on <distribution> (from the facts), and makes atd run and start at boot. Run it with --check --diff first, then for real, then again to see everything ok. Finally change /etc/motd by hand, run the playbook once more, and watch it put the content back.

Hints

• ansible-core on RHEL relatives, ansible on Ubuntu.
• ssh-keygen; on one machine you can append your public key to ~/.ssh/authorized_keys yourself; ssh 127.0.0.1 true once to accept the host key.
• ansible lab -i inventory.ini -m ping, -m setup -a 'filter=ansible_distribution*'.
• ansible.builtin.package, ansible.builtin.copy with content:, ansible.builtin.service; become: true and -K for alice's sudo password; ansible-playbook --check --diff.