Certified Kubernetes Application Developer (CKAD) Practice Test

Which of the following best describes a 'failureThreshold' in the context of probes?

1. The number of times a probe must fail before the container is restarted

2. The number of successful checks required for a container to be considered healthy

3. The maximum amount of time a probe can run

4. The frequency at which a probe runs

The correct answer is: The number of times a probe must fail before the container is restarted

The definition of 'failureThreshold' in the context of Kubernetes probes specifically relates to determining when a container should be restarted due to failures in the probe checks. The 'failureThreshold' is the number of consecutive failures that are permitted before the system considers the container unhealthy and initiates a restart. This mechanism helps ensure that transient failures do not lead to unnecessary restarts of a container. In a practical scenario, if a probe consistently fails as per the specified failureThreshold, this indicates a more significant issue with the application or service running in the container. Thus, once the failure count reaches the designated threshold, the Kubernetes system initiates a restart of the container to attempt recovery. Other options such as the number of successful checks needed for health confirmation, maximum duration a probe can run, or the frequency of probe execution describe different aspects of health checks in Kubernetes and do not directly relate to the failure threshold concept.