You now understand load balancing.
Load balancers distribute traffic across multiple servers.
Algorithms: Round Robin, Weighted, Least Connections, IP Hash, Random. Choose based on your use case.
Layer routes on IP/port. Layer routes on HTTP content.
Health checks detect failed servers. Active (ping) or Passive (monitor errors).
Avoid making the load balancer a SPOF. Use Active-Passive or Active-Active setups.
Load balancers appear in every system design. Draw them between clients and application servers.