Redlock debates matter because ElastiCache is not a consensus system. Consistent hashing for sharding workers and ALB target stickiness—with DynamoDB conditional writes as the boring alternative.
Exactly-once is a myth end-to-end—but idempotent consumers plus event stores get you close. CQRS read models on DynamoDB streams, Kinesis, and EventBridge replay semantics.
Protobuf on the wire saves bytes; GraphQL saves round trips until resolvers N+1 your Aurora cluster. ALB gRPC, AppSync, and consumer-driven contracts with Pact.
C10k is solved until syscall overhead and context switches eat your Graviton cores. epoll, sendfile, and SO_REUSEPORT behaviors on EC2—and why Lambda caps concurrency differently.
Heap too small triggers G1 humongous allocations; too large balloons pause times on Graviton. Corretto on ECS/EKS/Lambda Java—when ZGC generational beats G1 for API heaps.
Consumer group rebalance storms stall processing longer than broker outages. This guide covers cooperative rebalancing, idempotent producers, and transactional reads on Amazon MSK—with when SQS FIFO is simpler.
Cluster upgrades and Karpenter consolidation look healthy in the console while PDB-blocked evictions freeze your node drain for 45 minutes. This guide wires minAvailable, maxUnavailable, and EKS managed node group semantics.
Ingesting every debug log to CloudWatch is how observability becomes a FinOps incident. Tail sampling with ADOT, Logs Insights, and Firehose to S3 for the long tail.
FIFO guarantees shrink throughput—and unbounded queues only move backpressure to your AWS bill. Ordering, flow control, and Amazon MQ dead-letter patterns vs Kinesis resharding.
Packet loss on mobile networks still punishes HTTP/1.1 head-of-line blocking—but HTTP/3 only helps if CloudFront terminates QUIC and your origin connection pools are sized for multiplexed streams. This guide connects Reno, Cubic, BBR, HPACK, and QUIC to ALB and CloudFront decisions.
Local JWT validation is fast until revocation lags bite you. When to introspect at Cognito, use API Gateway JWT authorizers, and add Verified Permissions for fine-grained authz.
Serializable sounds safest until your checkout times out under row locks. This guide maps READ COMMITTED, REPEATABLE READ, and SERIALIZABLE to RDS/Aurora defaults—and when DynamoDB conditional writes are the BASE alternative.
