CKA Application Lifecycle 3

Question 1

You have a pod that must read a database password at startup. Which Kubernetes object is most appropriate for storing this credential?

Accepted Answer

Secret

Answer

Secrets are designed for sensitive data like passwords and are base64-encoded at rest; ConfigMaps are for non-sensitive configuration data.

Question 2

How do you inject all key-value pairs from a ConfigMap as environment variables into a container?

Accepted Answer

Use `envFrom.configMapRef` in the container spec

Answer

`envFrom.configMapRef` injects all keys from a ConfigMap as environment variables in one declaration, avoiding the need to reference each key individually.

Question 3

A pod mounts a Secret as a volume. The Secret is updated in the cluster. When will the pod see the updated values?

Accepted Answer

Within the kubelet sync period (typically up to 1 minute)

Answer

Kubelet periodically syncs mounted Secrets and ConfigMaps; changes propagate to the mounted volume within the kubelet's cache TTL, typically up to ~1 minute.

Question 4

What happens to environment variables in a running pod when a referenced ConfigMap is updated?

Accepted Answer

They update only after the pod is restarted

Answer

Environment variables are set at container startup and do not change during the container's lifetime; the pod must be restarted to pick up ConfigMap changes injected as env vars.

Question 5

You want to create a ConfigMap from a directory of config files. Which command accomplishes this?

Accepted Answer

kubectl create configmap myconfig --from-file=./config-dir/

Answer

`kubectl create configmap --from-file=<dir>` creates a ConfigMap where each file in the directory becomes a key (filename) with its contents as the value.

(CKA) Certified Kubernetes Administrator Practice Test

(CKA) Certified Kubernetes Administrator Practice Test

CKA Application Lifecycle 3