What does dynamic configuration enable in Envoy?

Dynamic configuration in Envoy allows for updating routing and service definitions at runtime without requiring a restart of the service. This capability is crucial for modern microservices architectures, where applications need to adapt to changes in traffic patterns, service availability, and other operational conditions on-the-fly.

By supporting dynamic configuration, Envoy can apply changes to its routing rules, cluster definitions, and other settings immediately, ensuring that services can respond to changes and optimize performance without downtime. This is especially beneficial in environments where continuous deployment and scaling are common, as it allows developers to make adjustments and improvements without disrupting ongoing operations. The flexibility provided by dynamic configuration is a key feature that enhances the resilience and adaptability of applications using Envoy.

The other options do not reflect the functionality of dynamic configuration: restarting the service for updates implies a static configuration approach, while limiting the number of service instances and providing fixed configurations does not take advantage of the dynamic capabilities that Envoy offers.