1. What is Envoy?
Ans:- Envoy is an open-source proxy designed for cloud-native applications, providing features like load balancing, service discovery, and observability.
2. What is the role of Envoy in microservices architectures?
Ans:- Envoy is often used as a sidecar proxy to manage communication between microservices, handling tasks like load balancing, retries, and timeouts.
3. Who maintains Envoy?
Ans:- Envoy is maintained by the Cloud Native Computing Foundation (CNCF) and has a vibrant open-source community.
4. What protocols does Envoy support?
Ans:- Envoy supports protocols such as HTTP/1.1, HTTP/2, gRPC, and TCP.
5. How does Envoy handle load balancing?
Ans:- Envoy employs various load balancing algorithms, including round-robin, least request, and random load balancing.
6. Can Envoy be used for WebSocket communication?
Ans:- Yes, Envoy supports WebSocket communication and can be configured accordingly.
7. What is the role of a filter in Envoy?
Ans:- Filters in Envoy allow users to modify and extend the behavior of the proxy, such as adding authentication or rate limiting.
8. How does Envoy support circuit breaking?
Ans:- Envoy has built-in support for circuit breaking, preventing cascading failures by breaking the circuit when a downstream service is failing.
9. What is the difference between Envoy and traditional load balancers?
Ans:- Envoy is more feature-rich and designed for modern microservices architectures, offering dynamic configuration and better observability.
10. How does Envoy support service discovery?
Ans:- Envoy integrates with service discovery systems like Consul or Kubernetes to dynamically discover and route traffic to available services.
11. What is the role of the control plane in Envoy?
Ans:- The control plane in Envoy is responsible for managing dynamic configuration and communicating changes to the proxy.
12. Can Envoy be used as an API Gateway?
Ans:- Yes, Envoy is often used as an API Gateway, providing features like rate limiting, authentication, and transformation.
13. How does Envoy handle retries in case of service failures?
Ans:- Envoy supports automatic retries with configurable retry policies to handle transient failures in downstream services.
14. What is the role of the Envoy xDS API?
Ans:- The xDS API (Discovery Service API) is used for dynamically configuring Envoy with information about clusters, routes, and listeners.
15. How does Envoy support mutual TLS (mTLS) authentication?
Ans:- Envoy can be configured to enforce mutual TLS authentication for secure communication between services.
16. Can Envoy be used with Kubernetes?
Ans:- Yes, Envoy can be integrated with Kubernetes as a sidecar proxy for communication between services.
17. How does Envoy handle rate limiting?
Ans:- Envoy supports rate limiting to control the amount of traffic allowed to a service based on specified policies.
18. What is the role of the Envoy Access Log Service (ALS)?
Ans:- ALS provides detailed access logs, allowing operators to monitor and analyze traffic patterns.
19. How does Envoy handle WebSocket communication?
Ans:- Envoy has native support for WebSocket communication, allowing it to handle bidirectional communication channels.
20. Can Envoy be used with gRPC services?
Ans:- Yes, Envoy is well-suited for managing communication with gRPC services and can handle features like load balancing and retries.
21. How does Envoy handle distributed tracing?
Ans:- Envoy can be configured to emit trace data to distributed tracing systems like Zipkin or Jaeger.
22. What is the role of Envoy in edge proxy scenarios?
Ans:- In edge proxy scenarios, Envoy can be used to manage traffic entering and leaving a network, providing features like TLS termination and rate limiting.
23. How does Envoy handle WebSockets and long-lived connections?
Ans:- Envoy supports WebSockets and long-lived connections efficiently, maintaining connection health and managing resources effectively.
24. What is the role of the Envoy Mobile project?
Ans:- Envoy Mobile extends Envoy’s capabilities to mobile devices, enhancing performance and observability for mobile applications.
25. How does Envoy support dynamic routing configurations?
Ans:- Envoy can dynamically update its routing configurations through the xDS API, allowing for flexible and scalable routing management.
26. Can Envoy be used in non-containerized environments?
Ans:- Yes, Envoy can be deployed in various environments, including virtual machines and bare-metal servers.
27. How does Envoy support health checking of services?
Ans:- Envoy performs health checking of services and dynamically adjusts routing based on the health status of the services.
28. What is the role of the Envoy Proxy Protocol?
Ans:- The Proxy Protocol allows Envoy to pass information about the original connection to the destination service.
29. How does Envoy handle security features like rate limiting and access control?
Ans:- Envoy provides security features through filters, allowing operators to configure rate limiting, access control, and other security policies.
30. What is the role of the Envoy Secret Discovery Service (SDS)?
Ans:- SDS is used to dynamically manage and distribute secrets, such as TLS certificates, to Envoy instances.
31. How does Envoy handle load balancing for gRPC services?
Ans:- Envoy provides advanced load balancing features for gRPC services, including weighted routing and connection pooling.
32. What is the role of the Envoy ALS gRPC API?
Ans:- The ALS gRPC API allows for programmatic access to Envoy’s access logs.
33. Can Envoy be used in conjunction with Istio?
Ans:- Yes, Envoy is the default proxy used in the Istio service mesh.
34. How does Envoy handle timeouts and retries in communication with downstream services?
Ans:- Envoy allows users to configure timeouts and retries, helping to ensure reliable communication with downstream services.
35. What is the role of the Envoy Proxy Lua filter?
Ans:- The Lua filter enables users to extend Envoy’s behavior by executing Lua scripts in the request and response processing pipeline.
36. How does Envoy support hot restarts for updates without downtime?
Ans:- Envoy supports hot restarts, allowing updates to be applied without downtime by seamlessly transitioning to a new Envoy process.
37. What is the purpose of the Envoy External Authorization filter?
Ans:- The External Authorization filter allows for delegating authorization decisions to an external service.
38. How does Envoy handle dynamic routing based on metadata?
Ans:- Envoy supports dynamic routing based on service metadata, allowing for flexible and fine-grained traffic management.
39. Can Envoy be used with OpenShift?
Ans:- Yes, Envoy can be integrated with OpenShift, providing a powerful proxy solution for communication between services.
40. How does Envoy handle protocol upgrades, such as HTTP/1.1 to HTTP/2?
Ans:- Envoy can be configured to handle protocol upgrades, allowing for seamless transitions between different versions.
41. What is the role of the Envoy StatsD filter?
Ans:- The StatsD filter allows for sending metrics to a StatsD server for monitoring and observability.
42. How does Envoy handle connection pooling for efficient resource utilization?
Ans:- Envoy supports connection pooling to efficiently manage resources and reduce latency in communication with downstream services.
43. What is the role of the Envoy ExtAuthz gRPC API?
Ans:- The ExtAuthz gRPC API allows for externalizing authorization decisions to an external service using gRPC.
44. How does Envoy handle WebSocket upgrades behind a load balancer?
Ans:- Envoy can be configured to handle WebSocket upgrades even when behind a load balancer.
45. Can Envoy be used as a standalone proxy without a service mesh?
Ans:- Yes, Envoy can be used as a standalone proxy to provide features like load balancing and security without a service mesh.
46. What is the role of the Envoy Bootstrap process?
Ans:- The Bootstrap process initializes and configures an Envoy instance, specifying parameters such as listening ports and upstream clusters.
47. How does Envoy handle route matching and path-based routing?
Ans:- Envoy supports powerful route matching capabilities, allowing for path-based routing and fine-grained control over traffic.
48. Can Envoy be used with cloud-native platforms other than Kubernetes?
Ans:- Yes, Envoy is a versatile proxy that can be used with various cloud-native platforms and environments.
49. How does Envoy handle dynamic updates to its configuration?
Ans:- Envoy dynamically updates its configuration through the xDS API, allowing for real-time adjustments.
50. What is the role of the Envoy Rate Limit service (RLS)?
Ans:- The Rate Limit service is used to perform rate limiting based on configured policies, preventing abuse and ensuring fair resource usage.
