A PodDisruptionBudget is a floor, not a ceiling: it names how many replicas of a workload must stay available while something voluntarily takes the rest away. The thing doing the taking is usually kubectl drain, a node autoscaler, or an operator compacting nodes. ...
Anti-affinity is the scheduler rule that keeps replicas apart. Where affinity says “run me next to these pods”, anti-affinity says “keep me away from them”, and the reason is almost always failure domains: if all three replicas land on one node, one node failure is a full outage. ...
Readiness and liveness answer different operational questions. Readiness asks whether this container should contribute to a Pod that accepts ordinary Service traffic now. Liveness asks whether restarting this container is the configured recovery action. Both can use HTTP, but sharing a protocol does not make their meanings interchangeable. Define the action you want before choosing the condition that triggers it. ...
nginx passive upstream health uses outcomes of real requests to decide whether a peer should temporarily stop receiving traffic. max_fails sets an unsuccessful-attempt threshold, while fail_timeout supplies both the counting interval and the unavailability period. These settings do not schedule periodic application probes. Active checks require a supported checking capability and configuration beyond this passive request-outcome policy. ...