Exam KCNA topic 1 question 36 discussion

Probes are used to determine if a container is running correctly and if it is ready to serve traffic. Kubernetes supports three types of probes: Liveness Probe Readiness Probe Startup Probe

Within Kubernetes, a "probe" refers to a diagnostic mechanism used by the kubelet to check the health of containers running within pods.Probes are configured within the PodSpec of Kubernetes pods and are used to determine if the containers within the pod are healthy and ready to serve traffic. There are three types of probes: Liveness Probe: Determines if the container is still running and healthy. If the liveness probe fails, Kubernetes restarts the container. Readiness Probe: Determines if the container is ready to serve traffic. If the readiness probe fails, the pod is removed from load balancers, and no traffic is routed to it. Startup Probe: Similar to the liveness probe, but only runs during the initial startup of a container. It helps delay the liveness and readiness probes until the application inside the container has started.

Think of a probe in Kubernetes like a heart rate monitor attached to a patient in a hospital. Just as the heart rate monitor continuously checks the patient's heart rate to ensure they are alive and functioning correctly, Kubernetes probes continuously monitor the health of containers to ensure they are running and capable of serving traffic. If the heart rate monitor detects irregularities or a lack of heartbeat, medical staff take action to revive or stabilize the patient. Similarly, if Kubernetes probes detect issues with a container, Kubernetes takes action to restart or replace the container, ensuring the application remains available and responsive.