Certified Kubernetes Application Developer (CKAD) Practice Test

The property used to define a readiness probe in a pod specification is correctly identified as spec.containers.*.readinessProbe. Readiness probes are essential in Kubernetes as they determine when a pod is ready to start accepting traffic. This is crucial for maintaining the health and reliability of applications running within containers.

When the readiness probe fails, the endpoints controller removes the pod's IP address from the list of endpoints, meaning that the pod will not receive any traffic until the probe indicates that it is ready again. This helps to prevent requests from being sent to containers that are not fully initialized or are experiencing issues.

The other options do not define readiness probes. For example, startupProbe is used to manage the startup lifecycle of a pod, and healthCheck is not a valid configuration in the Kubernetes specification. There is also no property called readinessConfig within the pod specification, further reinforcing that the correct property for specifying readiness probes is indeed readinessProbe. Understanding this distinction is critical for proper application deployment and management in Kubernetes environments.