This approach ensures idempotency and clarity. Specifying ‘state: present’ for an exact version guarantees the correct package is installed without unintended upgrades. The ‘service’ module correctly accepts both ‘state’ and ‘enabled’ parameters in a single, idempotent task. Using separate modules (yum, service) is preferred over shell commands for portability and error handling.

In Ansible variable precedence, `–extra-vars` (or `extra_vars`) has one of the highest priorities. It overrides most other variable sources, including role defaults (`defaults/main.yml`) and role vars (`vars/main.yml`). This allows for maximum flexibility and runtime overrides when executing playbooks.

`ansible-vault create` is the standard and most secure method for creating a new encrypted file from scratch. It prompts for a password (avoiding plaintext password files in the initial creation unless strictly necessary) and opens your configured editor, ensuring the sensitive data is never written to disk in plaintext during the creation process.

The `firewalld` module’s `immediate=yes` parameter is key. It applies the change to both the runtime configuration and the permanent configuration in a single, idempotent operation. This eliminates the need for a separate reload command and ensures the rule is active immediately and will persist after a reboot.

This is the standard, idempotent flow. The `filesystem` module creates the filesystem if it doesn’t exist. The `mount` module with `state: mounted` performs two actions: it adds an entry to `/etc/fstab` (`state: present` behavior) and ensures the filesystem is mounted at the time the task runs. This ensures persistence across reboots.

The `search` test is used to find a substring within a string. The `is search()` syntax is the correct Jinja2 test for this purpose. Using `==` checks for exact equality, `in` checks for a substring in a list/string but has different semantics, and checking the return code (`rc`) only confirms failure, not the specific error message.

The `.j2` extension is a common convention for Jinja2 template files. The `copy` module transfers files as-is, while the `template` module renders the Jinja2 templating syntax (like variables `{{ }}` and loops) before transferring the final content. Using `copy` on a `.j2` file would likely copy the un-rendered template syntax, leading to invalid configuration.

Both the `yum` and `package` modules accept a list directly for the `name` parameter. Providing the list variable (rendered with `{{ }}`) allows the module to install all packages in the list in a single transaction, which is more efficient and atomic than looping through them individually with `with_items`.

This mimics exception handling in programming. When a task in a `block` fails, execution jumps immediately to the `rescue` section. After the `rescue` section completes, the `always` section runs unconditionally. This structure is useful for error recovery (`rescue`) and cleanup operations (`always`).

This approach ensures idempotency and clarity. Specifying ‘state: present’ for an exact version guarantees the correct package is installed without unintended upgrades. The ‘service’ module correctly accepts both ‘state’ and ‘enabled’ parameters in a single, idempotent task. Using separate modules (yum, service) is preferred over shell commands for portability and error handling.0