Article 16: Resilience Patterns in Microservices

1. Objective

Learn how to make microservices resilient to failures using proven patterns.

2. Key Concepts

• Resilience
• Fault tolerance
• Graceful degradation

3. Why Resilience Is Needed

Failures are inevitable:

• Network issues
• Service crashes
• Slow responses

4. Key Resilience Patterns

• Circuit Breaker
• Retry
• Timeout
• Bulkhead
• Fallback

5. Circuit Breaker Pattern

Request -> Circuit Breaker -> Service
           (open / closed)

6. Hands-On: Resilience4j Example

@CircuitBreaker(name = "orderService", fallbackMethod = "fallback")
public String callService() {
    return restTemplate.getForObject(url, String.class);
}

public String fallback(Exception e) {
    return "Fallback response";
}

7. Retry & Timeout

• Retry transient failures
• Always configure timeouts

8. Common Mistakes

• Infinite retries
• No fallbacks
• Ignoring timeout configuration

9. Interview Notes

• Circuit breaker prevents cascading failures
• Resilience improves system stability

10. Summary

Resilience patterns keep systems alive under failure.

11. What’s Next

Containerize and deploy microservices.