Configuration Management and Feature Flags

A service is code plus configuration: database URLs, timeouts, log levels, feature flags, and kill switches.

In microservices, configuration spreads across many services, environments, and regions. Some values also need to change at runtime without a deploy.

Good configuration management separates code changes from behavior changes, so teams can adjust safely and quickly.

This chapter covers static and dynamic configuration, environment-based config, centralized config services, feature flags, and the flag debt caused by forgotten temporary flags.