readme.md

Lab: Using the set_fact Module in Ansible

Overview

In this lab, you will learn how to use the set_fact module in Ansible to dynamically define custom facts (variables) during playbook execution and utilize them in subsequent tasks. This approach is particularly useful for assigning or calculating values during runtime.

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Objectives

• Understand how to use the set_fact module.
• Dynamically define custom variables during playbook execution.
• Utilize the defined variables in subsequent tasks.

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Prerequisites

• Basic knowledge of Ansible playbooks and tasks.
• Ansible installed on your ansible machine.
• Access to target hosts in the webservers inventory group.

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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 facts_playbook.yml.

2. Define the play with the following content:

   ---
   - name: A play with custom variables (facts)
     hosts: webservers
     gather_facts: no

   Explanation:

   • gather_facts: no disables automatic fact-gathering, allowing you to define custom facts manually.

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Step 2: Define Facts Using the set_fact Module

1. Add tasks to define custom facts using the set_fact module. These facts can be static values or dynamically calculated.

     tasks:
       - name: Setting custom facts
         set_fact:
           fact_one: "Hello"
           fact_other: "Bye"
           john_fact: "Doe"

   Explanation:

   • fact_one, fact_other, and john_fact are custom variables that will be available for the remainder of the playbook.

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Step 3: Utilize Facts in Subsequent Tasks

1. Use the defined facts in tasks. For example, use the debug module to print their values:

       - name: Display john_fact
         debug:
           var: john_fact
   
       - name: Display fact_other
         debug:
           var: fact_other

   Explanation:

   • The debug module helps verify that the facts are set correctly and can display their values during playbook execution.

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Step 4: Execute the Playbook

1. Save the playbook as facts_playbook.yml.

2. Run the playbook using the following command:

   ansible-playbook facts_playbook.yml

3. Observe the output. The values of john_fact and fact_other will be displayed as defined in the set_fact module.

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Conclusion

In this lab, you’ve learned how to use the set_fact module to dynamically define and utilize custom variables during playbook execution. This powerful feature allows you to create flexible and dynamic playbooks tailored to specific scenarios or conditions. Keep practicing with set_fact to enhance your Ansible automation skills! 👏