load balancing

A staple of every networking round, and the follow-up is always about TLS termination. Knowing which layer sees what decides most of the answer.

X-Forwarded-For, PROXY protocol v1 and v2, and the trust boundaries between them. Get the layer wrong and your rate limiting, geo rules and audit trails all key off the balancer's address.

Multi-AZ is the answer and the reason matters more than the acronym. Each tier fails differently, and the database is the one where high availability means a failover with a real gap, not zero interruption.

One is layer 4 and regional, one is layer 7 and regional, one is layer 7 and global. Answer on those two axes and the choice makes itself, including when you need two of them together.

Service types choose how an application is exposed. Follow the actual traffic path: cloud controllers can target nodes or pods, and internal exposure differs from public exposure.

Three API servers behind one health-checked endpoint, etcd on its own quorum, leader election everywhere else. The scored part is naming what degrades quietly before anything alerts.