How does Envoy implement policy enforcement?

Envoy implements policy enforcement predominantly by ensuring that all requests adhere to defined security and routing policies. This is crucial for maintaining the integrity, security, and performance of microservices in a distributed system. When Envoy handles inbound and outbound traffic, it evaluates requests against the set policies to determine whether to allow or deny them, based on criteria such as authentication, authorization, and service-specific rules.

By integrating policy checks throughout the request and response lifecycle, Envoy allows operators to enforce rules consistently across services, ensuring compliance and reducing the risk of unauthorized access or data breaches. This capability is essential in modern cloud-native environments where services need to communicate securely and efficiently.

In contrast, the other options do not align with how Envoy is designed to operate. Logging requests without filtering would fail to enforce any security measures. Allowing all requests regardless of established policies would undermine the entire purpose of implementing security and routing policies. Lastly, enforcing policies only on error responses would be inadequate, as it would leave numerous requests unchecked until a problem arises, rather than preventing potential issues in the first place.