DO092 – Developing Cloud-Native Applications with Microservices Architectures — Lesson 2: Microservices Boundaries, APIs, Data Ownership, and Integration Patterns

Learning Objectives

• Configure the main services, objects, and controls involved in service boundaries, API contracts, and data ownership.
• Apply integration patterns and distributed transactions while preserving reviewable technical evidence.
• Recognize and correct the risk where a valid command creates the wrong outcome because variables, identity, or sequencing are incorrect.

Detailed Topics

• service boundaries: 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.
• API contracts: 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.
• data ownership: 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.
• integration 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.
• distributed transactions: 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 microservices boundaries, apis, data ownership, and integration patterns by tracing the relevant architecture, commands, configuration, messages, and evidence. The walkthrough highlights how a valid command creates the wrong outcome because variables, identity, or sequencing are incorrect and shows how to isolate the cause without masking dependent issues.

Hands-On Exercise

Implement the core workflow and compare expected versus observed behavior for Microservices Boundaries, APIs, Data Ownership, and Integration Patterns. 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 service boundaries in the stated scenario.
• Compare two approaches for integration patterns 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 configuration, permissions, sequencing, and functional behavior separately, then correlate logs, events, commands, and configuration history. Do not accept the initial assumption that a valid command creates the wrong outcome because variables, identity, or sequencing are incorrect; confirm the cause with a reproducible retest.

Validation Checklist

• The required configuration, permissions, sequencing, and functional behavior 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 Microservices Boundaries, APIs, Data Ownership, and Integration Patterns, 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.