Comparison
Layer 7 load balancingvsLoad balancer
Layer 7 load balancing
the proxy reads the request, routes on the path, retries the failed one on another backend and adds a trace header.
Distributing traffic per request at the application layer, which requires terminating and parsing the protocol. It buys path and header routing, per-request balancing, retries, timeouts, rewriting and observability, and it costs CPU, latency and the need to handle certificates. Nearly everything a service mesh or an ingress does that sounds clever is this distinction and nothing more.
Full entry →Load balancer
one address takes all the traffic and spreads it across the instances, skipping the ones failing their health check.
A component distributing requests across backends and removing unhealthy ones from rotation. Layer 4 balances connections and is fast and protocol-agnostic; layer 7 understands HTTP and can route, retry and rewrite. Its algorithm matters under uneven request costs: round robin sends work to a saturated instance, least-connections does not.
Full entry →