Linux Foundation Kubernetes Application Developer CKAD Question # 4 Topic 1 Discussion

Solution:

To have Kubernetes automatically restart a pod when an endpoint returns an HTTP 500 on the /healthz endpoint, you will need to configure liveness and readiness probes on the pod.

First, you will need to create a livenessProbe and a readinessProbe in the pod's definition yaml file. The livenessProbe will check the /healthz endpoint, and if it returns an HTTP 500, the pod will be restarted. The readinessProbe will check the /started endpoint, and if it returns an HTTP 500, the pod will not receive traffic.

Here's an example of how you can configure the liveness and readiness probes in the pod definition yaml file:

apiVersion: v1

kind: Pod

metadata:

name: probe-pod

spec:

containers:

- name: probe-pod

image:

ports:

- containerPort: 8080

livenessProbe:

httpGet:

path: /healthz

port: 8080

initialDelaySeconds: 15

periodSeconds: 10

failureThreshold: 3

readinessProbe:

httpGet:

path: /started

port: 8080

initialDelaySeconds: 15

periodSeconds: 10

failureThreshold: 3

The httpGet specifies the endpoint to check and the port to use. The initialDelaySeconds is the amount of time the pod will wait before starting the probe. periodSeconds is the amount of time between each probe check, and the failureThreshold is the number of failed probes before the pod is considered unresponsive.

You can use kubectl to create the pod by running the following command:

kubectl apply -f .yaml

Once the pod is created, Kubernetes will start monitoring it using the configured liveness and readiness probes. If the /healthz endpoint returns an HTTP 500, the pod will be restarted. If the /started endpoint returns an HTTP 500, the pod will not receive traffic.

Please note that if the failure threshold is set to 3, it means that if the probe fails 3 times consecutively it will be considered as a failure.

The above configuration assumes that the application is running on port 8080 and the endpoints are available on the same port.