Ansible Roles - Role Defaults

1. Introduction

In Ansible, roles are a way to organize playbooks and reuse code. Role defaults are variables defined within the role that provide default values for those variables. This lesson will delve into how to define and use role defaults effectively.

2. Key Concepts

• Roles: A method for organizing Ansible code.
• Defaults: Predefined variable values within a role.
• Overriding: Users can override defaults by providing their own values.

3. Defining Defaults

Defaults are defined in a `defaults/main.yml` file within a role. This file should contain key-value pairs that represent the default settings for the role.

# roles/my_role/defaults/main.yml
my_variable: "default_value"
my_other_variable: 42
            

4. Using Defaults

To use the defined defaults in your role, you reference them in your tasks or templates using the variable name. If a user specifies a value for the variable, that value will take precedence over the default.

# roles/my_role/tasks/main.yml
- name: Display variable value
  debug:
    msg: "The value is {{ my_variable }}"
            

If my_variable is not explicitly set by the user, it will default to "default_value".

5. Best Practices

• Always define meaningful defaults that provide a good starting point for users.
• Document your defaults clearly to help users understand their purpose.
• Use descriptive variable names to avoid confusion.
• Consider using ansible-lint to check for common issues in your roles.

6. FAQ