Core Architecture & Building Blocks of Load Balancers - Quiz New

Q1. Which of the following statements about active vs. passive health checks is correct? A) Passive checks proactively send pings to detect failures.
B) Active checks rely solely on observing real user traffic.
C) Passive checks can catch issues under load that basic active probes might miss.
D) Active checks remove the need for any fail-out threshold.

Q2. True or False: If a load balancer uses a 5-tuple hash, changing the source port on a new connection can lead to a different backend server. True
False

Q3. Which technique is MOST precise at ensuring each user is consistently routed to the same server in an HTTP-based application? A) IP Affinity (Client IP hashing)
B) Cookie-Based Session Persistence
C) Passive Health Checks
D) VRRP

Q4. True or False: Cookie-based persistence typically only works for HTTP(S) traffic and requires that the client accept cookies. True
False

Q5. Which of the following is a valid trade-off when choosing TLS termination at the load balancer (LB) versus TLS passthrough? A) Termination at the LB offers end-to-end encryption but limits the LB’s ability to inspect traffic.
B) Passthrough forces the LB to handle certificate management but allows deeper content inspection.
C) Termination at the LB enables content-based routing and offloads encryption from the backend servers.
D) Passthrough provides partial encryption and partial LB inspection capabilities.

Q6. True or False: In TLS passthrough mode, the load balancer can still insert HTTP cookies for session persistence. True
False

Q7. Which statement about graceful deregistration (connection draining) is FALSE? A) It stops sending new traffic to a server marked for removal.
B) It immediately drops all active connections on a deregistered server.
C) It allows existing sessions or connections to complete before fully removing a server.
D) It helps avoid disrupting users during scale-in or maintenance events.

Q8. True or False: A load balancer’s data plane handles real-time packet forwarding, while the control plane handles configuration, health checks, and server registration. True
False

Q9. In a dynamic auto-scaling scenario, how does a new server typically become available to receive traffic from the load balancer? A) The new server must manually inject itself into the load balancer’s data plane code.
B) An API call or service discovery mechanism notifies the LB’s control plane to register it.
C) The user must physically plug the server into the same VLAN as the LB.
D) The LB automatically scans all IP addresses in the subnet and picks new servers.

Q10. True or False: Session persistence can sometimes lead to imbalanced load if certain users have significantly heavier usage. True
False

Q11. Which of these is a main benefit of separating control plane and data plane in load balancers? A) It simplifies certificate installation on the servers.
B) It allows the data plane to continue forwarding traffic even if the control plane is busy or restarted.
C) It ensures no external dependencies are needed for traffic management.
D) It prohibits session stickiness from being configured.

Q12. True or False: VRRP (Virtual Router Redundancy Protocol) can be used in on-premises setups to enable a shared virtual IP between two load balancer nodes for high availability. True
False

Q13. Which statement BEST describes the concept of fail-out/fail-in thresholds in health checks? A) LB immediately removes a server after the first failed check.
B) LB requires multiple consecutive failures to mark a server unhealthy, and multiple consecutive successes to mark it healthy again.
C) LB only uses passive checks to decide if a server is healthy.
D) LB never reintegrates a server after it has failed a health check.

Q14. True or False: In an active/active LB HA setup using BGP anycast, multiple LB instances can advertise the same IP address, allowing traffic to be distributed among them. True
False

Q15. Which of the following is NOT a common session persistence technique? A) Client IP Affinity
B) HTTP Cookie-Based Affinity
C) Layer-4 5-Tuple Hashing
D) Custom Header/Token Affinity

Q16. True or False: If load balancers rely solely on passive health checks, a server that fails during a period of no traffic might stay in rotation undetected. True
False

Q17. Which is a potential drawback of cookie-based session persistence? A) It can lead to issues when multiple NATed clients share one IP.
B) It only provides connection stickiness for the duration of a single TCP connection.
C) It relies on the client’s browser to accept and return cookies.
D) It cannot be used on HTTP(S) protocols.

Q18. True or False: Session replication on the application side can sometimes remove the need for sticky sessions at the load balancer. True
False

Q19. When using a stateful (connection table-based) LB approach for flow hashing, what is one main drawback compared to a stateless hash? A) It cannot handle dynamic server membership at all.
B) It uses more memory to store active connection mappings.
C) It’s unable to do any health checks on backends.
D) It is incompatible with TLS termination.

Q20. True or False: In many cloud environments, the provider’s LB service handles the HA aspect behind the scenes, so you typically don’t configure VRRP or BGP yourself. True
False

system-design