Systems Architecture & Distributed Systems Topics
Large-scale distributed system design, service architecture, microservices patterns, global distribution strategies, scalability, and fault tolerance at the service/application layer. Covers microservices decomposition, caching strategies, API design, eventual consistency, multi-region systems, and architectural resilience patterns. Excludes storage and database optimization (see Database Engineering & Data Systems), data pipeline infrastructure (see Data Engineering & Analytics Infrastructure), and infrastructure platform design (see Cloud & Infrastructure).
Consensus and Coordination Algorithms
How independent nodes agree on shared state: Paxos and Raft, leader election, quorum reads and writes, distributed locks, coordination services such as ZooKeeper or etcd, and Byzantine fault tolerance for replicas that cannot be trusted. Covers split-brain avoidance, fencing tokens, and the cost of coordination on throughput and latency. Frames when consensus is required versus when it can be designed away.
Distributed Systems Security and Trust
Security problems that exist because a system is distributed: keeping trust state correct while it propagates across many services, clusters and regions. Covers credential, token and certificate revocation under eventual consistency and network partitions; fleet-wide rotation of signing keys, secrets and trust anchors without outages (key rollover and grace windows, canary rotation, recovery from a compromised root); distributed authorization (replicated policy decision points, cached decisions, fail-open versus fail-closed when an auth dependency degrades); propagating caller identity and permissions through service call chains; tamper-evident audit trails across services and regions (hash chains, Merkle proofs, ordering events with imperfect clocks); Byzantine and partially trusted participants; cross-cluster and cross-organization trust federation; securing shared distributed components such as caches and message brokers against injection, replay and cross-tenant access; protecting data in transit across region boundaries; and tenant isolation as a security blast-radius boundary. Steady-state mTLS, service-mesh identity and network segmentation mechanics are covered by zero-trust service-to-service security; single-system cryptography and KMS basics by applied cryptography.