🛠️ Advanced Fault Tolerance in Distributed Systems

Welcome back to The Code Hut Distributed Systems series! In this post, we’ll explore advanced fault tolerance techniques, including retries, circuit breakers, and recovery strategies for distributed systems.

⚠️ Why Fault Tolerance Matters

Distributed systems are prone to partial failures, network issues, and service outages. Fault tolerance ensures your system continues to operate and recover gracefully.

1. 🔁 Retry Strategies

• 🔹 Simple Retry: Retry a failed operation a fixed number of times.
• ⏳ Exponential Backoff: Increase the wait time between retries to reduce load.
• 🎲 Jitter: Add randomness to backoff to avoid thundering herd problems.

💻 Java Example: Retry with Exponential Backoff

int retries = 5;
long wait = 100; // initial backoff in ms

for (int i = 0; i < retries; i++) {
    try {
        remoteService.call();
        break; // success
    } catch (Exception e) {
        Thread.sleep(wait);
        wait *= 2; // exponential backoff
    }
}

2. 🛡️ Circuit Breakers

Circuit breakers prevent cascading failures by stopping requests to failing services.

• 🔒 Closed: Requests flow normally.
• ⛔ Open: Requests are blocked due to failures.
• ⚖️ Half-Open: Test the service with limited requests before fully closing.

💻 Java Example: Circuit Breaker with Resilience4j

CircuitBreaker circuitBreaker = CircuitBreaker.ofDefaults("service");

Supplier decorated = CircuitBreaker
    .decorateSupplier(circuitBreaker, () -> remoteService.call());

Try result = Try.ofSupplier(decorated);

3. 🏗️ Bulkheads

Isolate failures by limiting resources for each service or component, preventing one failure from affecting the entire system.

4. 🔧 Recovery Techniques

• 🛠️ Fallback methods when service calls fail
• 🌱 Graceful degradation of features
• 🔄 State reconciliation after failures

Next in the Series

In the next post, we’ll cover Testing Strategies for distributed systems, ensuring reliability and correctness under complex scenarios.

Label for this post: Distributed Systems