Comparison
Readiness probevsStartup probe
Readiness probe
the instance says "not yet" while the cache warms, so the load balancer keeps traffic off it until it is genuinely able to serve.
A health check whose failure means "stop sending traffic", without restarting the instance. This is the probe that may legitimately consider dependencies, since removing one instance from rotation is recoverable. Conflating it with liveness is one of the most common Kubernetes configuration mistakes.
Full entry →Startup probe
the application takes ninety seconds to warm up, and this is what stops the health checker killing it at thirty.
A health check that runs only during start-up, suspending the other probes until the process reports ready for the first time. It exists to solve one specific bug: a slow-starting application in a restart loop because its liveness check began before it was ever alive. Without it the only fix is a liveness delay long enough to also delay detection of genuine hangs for the rest of the workload's life.
Full entry →