Red Hat System Administration III: Linux Automation (AU294) – RHEL 10 — Lesson 2: Playbooks, Tasks, Modules, Variables, Facts, and Handlers

Learning Objectives

• Explain the structures, services, data, settings, roles, and dependencies governing YAML playbook structure and task sequencing.
• Implement and validate module selection, variables and facts, and handlers and idempotence using reviewable evidence.
• Evaluate the condition where a change succeeds in one environment but fails elsewhere because inventory, policy, version, or runtime assumptions differ and select a proportionate corrective response.

Detailed Topics

• YAML playbook structure applied to the course scenario, expected platform behavior, dependencies, controls, and evidence.
• task sequencing applied to the course scenario, expected platform behavior, dependencies, controls, and evidence.
• module selection applied to the course scenario, expected platform behavior, dependencies, controls, and evidence.
• variables and facts applied to the course scenario, expected platform behavior, dependencies, controls, and evidence.
• handlers and idempotence applied to the course scenario, expected platform behavior, dependencies, controls, and evidence.

Instructor Demonstration

The instructor traces a Linux operations team replacing manual server changes with controlled, reusable automation across a RHEL 10 estate. The walkthrough connects navigation, commands, configuration logic, system messages, and evidence captured in the RHEL automation design, playbook library, validation record, and operational handover portfolio. It also tests the exception where a change succeeds in one environment but fails elsewhere because inventory, policy, version, or runtime assumptions differ.

Hands-On Exercise

Complete a controlled Red Hat exercise covering Playbooks, Tasks, Modules, Variables, Facts, and Handlers and preserve the verified result in the RHEL automation design, playbook library, validation record, and operational handover portfolio.

1. Confirm scope, prerequisites, versions, identities, dependencies, and acceptance criteria.
2. Execute the workflow while recording commands, settings, outputs, events, and system messages.
3. Test normal behavior, one boundary condition, and the stated exception.
4. Document corrections, evidence, ownership, retest criteria, rollback, and handover actions.

Scenario Analysis

• Identify which object, service, policy, setting, or sequence most strongly influences YAML playbook structure.
• Compare two defensible responses and explain technical, security, operational, and support trade-offs.
• Determine how the RHEL automation design, playbook library, validation record, and operational handover portfolio should be approved, retained, retested, and updated.

Troubleshooting Guidance

Start where expected behavior first differs from the observed result. Check prerequisites, identity, configuration order, version compatibility, connectivity, status, resource limits, and evidence separately. Treat “a change succeeds in one environment but fails elsewhere because inventory, policy, version, or runtime assumptions differ” as a hypothesis until commands, logs, settings, and retest outcomes confirm the cause.

Validation Checklist

• Required platform components, identities, permissions, settings, and dependencies are present.
• The RHEL automation design, playbook library, validation record, and operational handover portfolio connects each conclusion to objective, reviewable evidence.
• Normal processing, a boundary condition, dependency behavior, and the stated exception were tested.
• Corrections, ownership, retest criteria, rollback, documentation, and operational handover are complete.

Lesson Outcome

Learners can apply Playbooks, Tasks, Modules, Variables, Facts, and Handlers, explain the resulting platform behavior, and defend the outcome through the RHEL automation design, playbook library, validation record, and operational handover portfolio.