What is the role of load balancers and health checks in maintaining service availability?

• A. They provide backup power to servers.
• B. They distribute traffic, detect unhealthy instances, and remove them from rotation to keep services responsive.
• C. They store user data for recovery.
• D. They encrypt data in transit but do not affect availability.

Answer: (B)

Load balancers maintain service availability by distributing traffic across multiple servers and by actively screening each server’s health. By spreading requests, they prevent any one server from becoming a bottleneck and help the system scale with demand. Health checks are automated probes that verify whether each instance can handle requests correctly and respond within acceptable timeframes. When a server fails a health check, it’s temporarily removed from the rotation so no traffic is sent to it, and requests are routed to healthy instances instead. This ongoing process keeps services responsive even if some components go down or are undergoing maintenance, reducing downtime and improving reliability. Encrypting data in transit or storing data are important for security and persistence, but they don’t directly ensure availability in the way load balancing and health checks do.