How can you ensure that the execution of an Ansible role does not change the system state upon re-runs?

To ensure that executing an Ansible role does not change the system state during repeated runs, it is necessary to ensure the role's idempotency. Idempotency means that running the role again will not change the system if it is already in the desired state.

How to do this:

• Use Ansible modules that are idempotent by default (e.g., file, package, service).
• Check conditions before making changes using parameters like creates, when, and others.
• Test the role multiple times and verify that no changes occur in subsequent runs (the Ansible output should not show changed: true).

Example:

- name: Install nginx
  apt:
    name: nginx
    state: present

If nginx is already installed, rerunning this task will not change the system or show any changes.