Software Architecture & Engineering

Historical OAuth 2.0 notes covering why OAuth is needed, the authorization flow, grant modes, token refresh, and scopes.

What a configuration center is, why it is needed, storage, client notification, service discovery, caching, canary release, and an example configuration-center database design.

What load balancing is, why it is needed, common algorithms, hardware/software/DNS choices, L2/L3/L7 approaches, and client-side versus server-side load balancing.

What a service registry is, why it is needed, server-side and client-side design, service discovery and routing, registry components, and ZooKeeper versus Eureka.

What an API gateway is, why it is needed, request forwarding and filtering, I/O models, common gateway components, BFF, and gateway aggregation.

What monitoring is, why microservices need it, and the three parts: logs, metrics, and tracing.

What tracing is, why it is needed, Span/Trace/Annotation data, sampling, collection approaches, storage, display, and common tracing components.

What fault tolerance is, service avalanche, and common techniques including timeouts, retries, rate limiting, circuit breaking, isolation, and degradation.

What log monitoring is, why it is needed, logging strategy, collection, aggregation, indexing and storage, analysis, and ELK.

What metrics monitoring is, why it is needed, what to monitor, how to collect and store metrics, alerting, and common metrics components.