How does Envoy handle service discovery?

Envoy handles service discovery primarily through integrations with service registries, which allows it to dynamically discover and interact with backend services. This capability is crucial in modern microservices architectures, where services may frequently change, and a static configuration would quickly become outdated.

Service registries maintain an up-to-date inventory of available services and their endpoints. When Envoy connects to a service registry, it can automatically receive updates about service availability, which enables efficient request routing and load balancing. As new instances of services are added or removed, Envoy can respond to these changes without requiring manual intervention or a restart, leading to increased resilience and flexibility in service management.

Using static configurations, relying on manual updates, or hard-coding addresses lacks the agility and robustness needed in dynamic environments. Static configurations limit the ability to adapt to changes and do not account for service scaling or failure. Manual interventions can lead to errors and downtime, while hard-coded addresses can become obsolete as services change. Therefore, leveraging service registries is the most effective method for Envoy to perform service discovery.