DO092 – Developing Cloud-Native Applications with Microservices Architectures — Lesson 3: Containers, Configuration, Resilience, Security, and Observability

Learning Objectives

• Evaluate security, resilience, integration, and exception handling for containers, externalized configuration, and resilience patterns.
• Apply security and observability while preserving reviewable technical evidence.
• Recognize and correct the risk where the design works normally but fails under scale, dependency loss, policy enforcement, or integration delay.

Detailed Topics

• containers: apply the concept to an application architecture team evaluating how to decompose and modernize a traditional enterprise application, record the relevant settings or decisions, and explain the operational consequence.
• externalized configuration: apply the concept to an application architecture team evaluating how to decompose and modernize a traditional enterprise application, record the relevant settings or decisions, and explain the operational consequence.
• resilience patterns: apply the concept to an application architecture team evaluating how to decompose and modernize a traditional enterprise application, record the relevant settings or decisions, and explain the operational consequence.
• security: apply the concept to an application architecture team evaluating how to decompose and modernize a traditional enterprise application, record the relevant settings or decisions, and explain the operational consequence.
• observability: apply the concept to an application architecture team evaluating how to decompose and modernize a traditional enterprise application, record the relevant settings or decisions, and explain the operational consequence.

Instructor Demonstration

The instructor demonstrates containers, configuration, resilience, security, and observability by tracing the relevant architecture, commands, configuration, messages, and evidence. The walkthrough highlights how the design works normally but fails under scale, dependency loss, policy enforcement, or integration delay and shows how to isolate the cause without masking dependent issues.

Hands-On Exercise

Introduce a controlled boundary condition and test recovery for Containers, Configuration, Resilience, Security, and Observability. Add verified outcomes to the microservices suitability assessment, service-boundary map, architecture risks, and modernization roadmap.

1. Confirm the scope, versions, access, dependencies, and success criteria.
2. Perform the workflow while recording commands, settings, output, and platform events.
3. Test one expected case and one controlled exception specific to this lesson.
4. Retest the correction and document ownership, rollback, and follow-up actions.

Scenario Analysis

• Identify which dependency most strongly influences containers in the stated scenario.
• Compare two approaches for security and explain the security, reliability, and support trade-offs.
• Decide what evidence must be retained in the microservices suitability assessment, service-boundary map, architecture risks, and modernization roadmap before operational acceptance.

Troubleshooting Guidance

Begin with the first observable difference from the expected result. Check security, integration, boundary conditions, and resilience separately, then correlate logs, events, commands, and configuration history. Do not accept the initial assumption that the design works normally but fails under scale, dependency loss, policy enforcement, or integration delay; confirm the cause with a reproducible retest.

Validation Checklist

• The required security, integration, boundary conditions, and resilience were checked and recorded.
• The normal path and a course-specific exception were tested.
• The microservices suitability assessment, service-boundary map, architecture risks, and modernization roadmap links conclusions to commands, configuration, logs, or other objective evidence.
• Corrective actions, rollback steps, ownership, and handover notes are complete.

Lesson Outcome

Learners can apply Containers, Configuration, Resilience, Security, and Observability, explain the observed Red Hat platform behavior, and support the result with a reviewable microservices suitability assessment, service-boundary map, architecture risks, and modernization roadmap.