OOMKilled containers in Kubernetes - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Identify the cause of OOMKilled status

You run kubectl get pods and see a pod with status OOMKilled. What does this status mean?

A The pod was terminated because it used more memory than its limit.

B The pod was restarted due to a network failure.

C The pod completed successfully and exited normally.

D The pod was deleted manually by the user.

💡 Hint

Think about what OOM stands for in computing.

OOMKilled means the pod was killed by the system because it used more memory than allowed by its limit.

❓ Troubleshoot

intermediate

Diagnose memory limits causing OOMKilled

You have a pod that keeps restarting with OOMKilled status. Which command helps you check the memory limits set on the pod?

A kubectl describe pod <pod-name>

B kubectl logs <pod-name>

C kubectl get nodes

D kubectl exec <pod-name> -- free -m

💡 Hint

Look for resource limits in pod details.

kubectl describe pod shows detailed pod info including memory limits and usage events.

❓ Configuration

advanced

Correct memory limit configuration to avoid OOMKilled

Which YAML snippet correctly sets a memory limit of 512Mi to prevent OOMKilled errors?

Kubernetes

apiVersion: v1
kind: Pod
metadata:
  name: example-pod
spec:
  containers:
  - name: example-container
    image: nginx
    resources:

A

      requests:
        memory: 512

B

      limits:
        memory: "512Mi"

C

      limits:
        memory: 512

D

      requests:
        memory: "512Mi"

💡 Hint

Memory limits must include units and be under 'limits'.

Memory limits must be set under limits with units like Mi to be valid.

✅ Best Practice

advanced

Best practice to prevent OOMKilled in production pods

What is the best practice to avoid OOMKilled errors in production Kubernetes pods?

A Disable memory limits to let pods use unlimited memory.

B Set CPU limits only and ignore memory settings.

C Set very high memory limits without requests to avoid killing.

D Set both memory requests and limits based on real usage metrics.

💡 Hint

Think about balancing resource allocation and stability.

Setting both requests and limits based on actual usage helps the scheduler and prevents OOMKilled.

🔀 Workflow

expert

Sequence to troubleshoot OOMKilled pod

Arrange the steps in the correct order to troubleshoot an OOMKilled pod:

A 3,1,2,4

B 2,1,3,4

C 1,3,2,4

D 1,2,3,4

💡 Hint

Start with pod status, then check config, then logs, then fix.

First check pod events to confirm OOMKilled, then inspect resource limits, then logs for clues, finally adjust limits.