readme.md

Lab Instructions: Using Conditionals in Ansible Playbooks

Overview

In this lab, you will learn how to use conditionals in an Ansible playbook. Specifically, you will understand how the when clause can be used to control the execution of tasks based on the value of a variable.

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Objectives

• Learn how to use the when clause to implement conditionals.
• Create a task that executes only under specific conditions.

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Prerequisites

• Basic understanding of Ansible playbooks.
• Ansible installed on your ansible machine.
• Access to target hosts in your inventory.

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Duration

Estimated Time: 20 minutes

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Instructions

Step 1: Set Up the Ansible Playbook

1. Create a new YAML file named conditional_playbook.yml.

2. Define the play's name, target hosts (all in this case), and whether to gather facts:

   ---
   - name: A conditional play
     hosts: all
     gather_facts: no

   Explanation:

   • hosts: all targets all hosts in the inventory.
   • gather_facts: no skips automatic fact gathering to keep the playbook simple.

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Step 2: Define a Variable

1. In the vars section, define a variable named epic and assign it a boolean value:

     vars:
       epic: true

   Explanation:

   • The variable epic will be used to control the execution of tasks.

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Step 3: Add a Conditional Task

1. Under the tasks section, add a task that prints a message "Hello A" if the variable epic is true:

     tasks:
       - name: Task A
         debug:
           msg: "Hello A"
         when: epic

   Explanation:

   • The when clause ensures the task runs only when the condition (epic: true) is met.

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Step 4: Execute the Playbook

1. Save the conditional_playbook.yml file.

2. Run the playbook using the following command:

   ansible-playbook conditional_playbook.yml

3. Observe the output. The task "Task A" will execute only if epic is set to true.

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Conclusion

In this lab, you've learned how to use conditionals in Ansible playbooks, progressing from simple boolean checks to complex production-ready logic.

What you learned:

• Basic when clause usage
• OS-specific conditional logic
• Environment-based configurations
• Complex multi-condition logic
• Real-world business logic implementation

Key Conditional Patterns:

• Single condition: when: variable
• Multiple conditions: when: condition1 and condition2
• List conditions: when: variable in ["value1", "value2"]
• Complex logic: when: (condition1 or condition2) and condition3

These patterns form the foundation for building sophisticated, environment-aware automation! 👏