Distributed systems are inherently complex. Understanding core patterns helps you build systems that handle failures gracefully and scale effectively.
The Challenges
Distributed systems must handle:
- Network failures (partitions, latency)
- Node failures (crashes, restarts)
- Timing issues (clock skew, ordering)
- Partial failures (some nodes fail, others don't)
The CAP theorem:
You can only guarantee two of three:
- Consistency: All nodes see same data
- Availability: Every request gets a response
- Partition tolerance: System works despite network issues
In practice, you must handle partitions, so choose between CP or AP.
Consensus Patterns
Leader Election
Distributed Locking
Consistency Patterns
Eventual Consistency
Read-Your-Writes Consistency
Partitioning Patterns
Consistent Hashing
Failure Handling Patterns
Circuit Breaker
Bulkhead
Retry with Exponential Backoff
Saga Pattern
Conclusion
Distributed systems require thinking about failures at every level. Use consensus for coordination, understand consistency tradeoffs, and implement resilience patterns like circuit breakers and bulkheads.
Test failure scenarios aggressively. The patterns that seem theoretical become critical when systems fail at 3 AM.