Question 1

Correct answer: A

A.

The provided Ansible playbook snippet demonstrates the correct usage of the with_first_found lookup to deploy environment-specific configuration files based on the environment variable. It first sets the 'env' variable to the value of the 'ENVIRONMENT' environment variable. Then, it uses with_first_found to look for the configuration file specific to the current environment in the 'configs/{{ env }}/config.yml' path. If the file is found, it is deployed to '/etc/myapp/config.yml'. If not found, it falls back to the default configuration file in 'configs/default/config.yml'.

Line-by-Line Code Explanation

1. - hosts: all

    Specifies the target hosts for the playbook.

    all means the playbook will apply to all hosts listed in the inventory file.

2. vars:

    Declares variables used within the playbook.

    Variables can be static or dynamically populated using lookups or other Ansible constructs.

3. env: "{{ lookup('env', 'ENVIRONMENT') }}"

    Defines a variable env using the lookup plugin.

    lookup('env', 'ENVIRONMENT') fetches the value of the ENVIRONMENT environment variable from the system running the playbook.

        Example: If ENVIRONMENT is set to production, then env will be production.

    If ENVIRONMENT is not set, env will be empty.

4. tasks:

    Lists the actions (tasks) that Ansible will perform on the target hosts.

5. - name: Deploy environment-specific config

    Provides a human-readable description of the task for logging and readability.

6. ansible.builtin.template:

    Specifies the template module (part of Ansible's core modules).

    This module processes a Jinja2 template file (src) and writes the rendered output to a destination file (dest) on the target host.

7. src: "{{ item }}"

    Indicates the source file for the template module.

    item is dynamically populated by the with_first_found loop.

        Ansible will search for files in the order specified in the loop and use the first one that exists.

8. dest: /etc/myapp/config.yml

    Specifies the destination path where the rendered template will be copied on the target host.

    In this case, it will save the configuration file to /etc/myapp/config.yml.

9. with_first_found:

    A looping construct that takes a list of file paths.

    The template module will use the first file in the list that exists on the Ansible controller (or in the repository).

10. - "configs/{{ env }}/config.yml"

    The first file path in the with_first_found list.

    Uses the env variable to construct the path dynamically based on the environment.

        Example: If env is production, the path becomes configs/production/config.yml.

11. - "configs/default/config.yml"

    A fallback file path if the environment-specific file does not exist.

    Ensures that the playbook still completes successfully by using a default configuration.

Execution Flow

    Ansible resolves the value of env based on the ENVIRONMENT environment variable.

    It checks the paths in the with_first_found list, starting with configs/{{ env }}/config.yml.

    If the environment-specific file is found, it is used; otherwise, the default file is applied.

    The selected file is processed as a Jinja2 template and saved to /etc/myapp/config.yml on the target host.