What happens when a load balancer fails and how do you handle this condition?

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Load Balancers Interview Questions

  1. [JUNIOR] What is a load balancer and why is it used?
  2. [MID] What are the common load balancing algorithms and how do they work?
  3. [MID] What is the difference between Layer 4 and Layer 7 load balancing?
  4. [JUNIOR] What are the key benefits of using a load balancer?
  5. [JUNIOR] What is a health check and why is it important for load balancers?
  6. [MID] What are sticky sessions and when would you use them?
  7. [MID] How does a load balancer decide which server to route a request to?
  8. [SENIOR] How do you eliminate the load balancer itself as a single point of failure?
  9. [JUNIOR] What are the different types of load balancers?
  10. [JUNIOR] What is round-robin load balancing?
  11. [JUNIOR] Where are load balancers typically placed in a system architecture?
  12. [JUNIOR] What is a reverse proxy and how does it relate to load balancing?
  13. [MID] How does SSL/TLS termination work at a load balancer?
  14. [MID] What is the least connections algorithm and when is it preferred over round-robin?
  15. [MID] What is the difference between an Application Load Balancer (ALB) and a Network Load Balancer (NLB)?
  16. [SENIOR] What is the difference between active-active and active-passive failover for load balancers?
  17. [SENIOR] How does consistent hashing work and why is it preferred over simple IP hashing in distributed systems?
  18. [SENIOR] What happens when a load balancer fails and how do you handle this condition?
  19. [JUNIOR] What happens to a system if there is no load balancer?
  20. [JUNIOR] What is the difference between hardware and software load balancers?
  21. [MID] How does IP hash-based load balancing work and what are its use cases?
  22. [MID] What is weighted round-robin load balancing and when would you use it?
  23. [MID] What is the difference between active and passive health checks?
  24. [SENIOR] How should connection draining work when removing or failing over a backend server?
  25. [SENIOR] What are the trade-offs of performing SSL termination at the load balancer versus end-to-end encryption?
  26. [SENIOR] What is the relationship between load balancing and auto-scaling?
  27. [SENIOR] How would you design a load balancer to handle millions of requests per second?
  28. [JUNIOR] What is the difference between vertical scaling and horizontal scaling in the context of load balancing?
  29. [MID] How can load balancers be used to improve application security?
  30. [MID] Can load balancers handle WebSocket connections and how?
  31. [MID] What is the difference between session affinity and sticky sessions?
  32. [SENIOR] How do load balancers protect against DDoS attacks?
  33. [SENIOR] What is the difference between geo-load balancing and global server load balancing?
  34. [SENIOR] How do cookie-based sticky sessions compare to IP-based session persistence?
  35. [EXPERT] How do you design health checks that are fast and meaningful without causing cascading failures?
  36. [EXPERT] What are the challenges of load balancing gRPC and HTTP/2 connections compared to HTTP/1.1?
  37. [MID] What is the difference between an ingress controller and a load balancer?
  38. [EXPERT] How does a load balancer handle the thundering herd problem when a backend server recovers?
  39. [EXPERT] What are the challenges of maintaining session persistence across multiple load balancer instances?
  40. [EXPERT] How does a load balancer handle long-lived connections like server-sent events or WebSocket streams at scale?
  41. [EXPERT] How does the power-of-d-choices algorithm improve upon traditional least connections load balancing?
  42. [EXPERT] What are the implications of ECMP (Equal-Cost Multi-Path) routing for load balancer design?
  43. [EXPERT] How does anycast routing work in the context of global load balancing?