high availability

Enterprise loops pair these topics because they test L2 literacy plus vendor coordination together. The scored insight is that LACP spreads flows, not packets, and needs the switch to agree.

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.

Anti-affinity is binary and falls over at scale; topologySpreadConstraints give you numeric skew control across labeled domains. The subtle parts are eligibility filtering before the skew math, and the fact that Kubernetes never rebalances anything for you.

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.

Hard versus soft rules, topology keys, weights that lose to everything else, and the IgnoredDuringExecution half nobody remembers. Placement shapes blast radius only when paired with disruption budgets.