This post is part of a series.
Part 1 - A deep dive into connection management challenges.
Part 2 - The nuances of HTTP parsing and why it’s harder than it looks.
Part 3 - The intricacies of service discovery.
Part 4 - Why Load Balancing at Scale is Hard.
Load Balancing
One of the most critical roles for a reverse proxy is load balancing requests across different upstream hosts. From a list of upstream servers, the proxy must decide where each incoming request should go.
The primary goals of load balancing are:
Optimal resource utilization: Evenly distribute load to maintain consistent performance and avoid hotspots. Resilience: Ensure that the failure of a single server doesn’t cause outsized impact on capacity or latency. Operational simplicity: Simplify capacity planning, monitoring, and failover by evenly balancing load.
Round-robin might work fine at small scale, but as systems grow, load balancing becomes far more complex due to many real-world challenges.
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