Load Balancing
load-balancing
System Design
DNS and Domain Routing
DNS (Domain Name System) is the phonebook of the internet. It translates human-readable domain names like 'google.com' into IP addresses that computers use to route traffic. This lesson explains how DNS resolution works, the hierarchy of DNS servers, common record types, and how DNS is used in system design for load balancing, failover, and global traffic routing.
Load Balancing Algorithms & Patterns
A load balancer is the traffic cop in front of every horizontally scaled service. This lesson covers the four scheduling algorithms you need to know (round-robin, least-connections, weighted, hash), the difference between Layer 4 and Layer 7 load balancing, how health checks pull dead nodes out of rotation, the role of sticky sessions and connection draining, and the tools (NGINX, HAProxy, ELB/ALB, Envoy) that implement all of this. By the end you can pick the right algorithm for a workload and explain to an interviewer exactly how a request finds its way from the load balancer to a healthy backend.