Exec probe configuration in Kubernetes - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the result of this exec probe configuration?

Given the following Kubernetes pod YAML snippet, what will be the status of the exec probe if the command exits with code 1?

Kubernetes

livenessProbe:
  exec:
    command:
    - /bin/sh
    - -c
    - exit 1
  initialDelaySeconds: 5
  periodSeconds: 10

A The probe succeeds and the container continues running.

B The probe fails and the container is restarted.

C The probe is ignored because exit code 1 is treated as success.

D The pod enters CrashLoopBackOff immediately.

💡 Hint

Exec probes consider exit code 0 as success; any other code means failure.

In Kubernetes exec probes, the command's exit code 0 means success. Any non-zero exit code means the probe failed, causing the container to be restarted if it's a liveness probe.

❓ Configuration

intermediate

Identify the correct exec probe configuration to check a file exists

Which exec probe configuration correctly checks if the file /tmp/healthy exists inside the container?

A

exec:
  command:
  - test
  - -f
  - /tmp/healthy

B

exec:
  command:
  - ls
  - /tmp/healthy

C

exec:
  command:
  - echo
  - /tmp/healthy

D

exec:
  command:
  - cat
  - /tmp/healthy

💡 Hint

Use a command that returns exit code 0 if the file exists.

The 'test -f /tmp/healthy' command returns exit code 0 if the file exists, making it suitable for exec probes.

❓ Troubleshoot

advanced

Why does this exec probe always fail?

A pod has this exec probe: livenessProbe: exec: command: - /bin/false initialDelaySeconds: 5 periodSeconds: 10 Why does the container keep restarting?

A Because the exec probe command is missing arguments.

B Because the initialDelaySeconds is too short for the container to start.

C Because /bin/false always exits with code 1, causing probe failure.

D Because the probe type should be HTTP, not exec.

💡 Hint

Check the exit code behavior of /bin/false.

/bin/false is a command that always exits with code 1, so the exec probe always fails, causing container restarts.

🔀 Workflow

advanced

Order the steps to add an exec readiness probe to a deployment

Put these steps in the correct order to add an exec readiness probe that checks if a service is ready:

A 2,1,3,4

B 3,1,2,4

C 1,3,2,4

D 1,2,3,4

💡 Hint

You must edit before applying, and verify last.

First edit the YAML, then add the readinessProbe, apply changes, and finally verify pod status.

✅ Best Practice

expert

Which exec probe command is best for checking a web server health inside a container?

You want an exec probe to check if a web server inside the container is healthy by verifying port 8080 is open. Which command is best?

A

exec:
  command:
  - nc
  - -z
  - localhost
  - "8080"

B

exec:
  command:
  - curl
  - -I
  - http://localhost:8080/health

C

exec:
  command:
  - telnet
  - localhost
  - 8080

D

exec:
  command:
  - ping
  - localhost

💡 Hint

Use a command that checks if a port is open without requiring HTTP response.

'nc -z localhost 8080' checks if port 8080 is open and returns exit code 0 if yes, suitable for exec probes.