OOMKilled containers in Kubernetes - Mini Project: Build & Apply

Understanding and Handling OOMKilled Containers in Kubernetes

📖 Scenario: You are managing a Kubernetes cluster running several containers. Some containers are unexpectedly stopping with the status OOMKilled, which means they ran out of memory and were terminated by the system.Your task is to identify these containers, set memory limits to prevent this, and verify the changes.

🎯 Goal: Learn how to detect OOMKilled containers, configure memory limits in pod specs, and confirm the containers run without being killed due to memory issues.

📋 What You'll Learn

Use kubectl commands to check pod status

Edit pod resource limits to set memory limits

Apply changes and verify pod status

Understand the meaning of OOMKilled in pod status

💡 Why This Matters

🌍 Real World

In real Kubernetes clusters, containers can be terminated if they use more memory than allowed. Setting memory limits helps keep the cluster stable and prevents one container from affecting others.

💼 Career

DevOps engineers and site reliability engineers often troubleshoot OOMKilled containers and configure resource limits to ensure applications run reliably in Kubernetes.

1

Check for OOMKilled containers

Run the command kubectl get pods to list all pods and then run kubectl describe pod myapp-pod to check the status of the pod named myapp-pod. Look for the term OOMKilled in the container status section.

Kubernetes

# Run kubectl commands to check pod status
# Your code here

Need a hint?

Use kubectl describe pod myapp-pod to see detailed container status including termination reasons.

2

Add memory limits to the pod configuration

Edit the pod configuration file myapp-pod.yaml to add a memory limit of 200Mi under resources.limits.memory for the container named myapp-container.

Kubernetes

kubectl get pods
kubectl describe pod myapp-pod
# Add memory limit 200Mi to myapp-container in myapp-pod.yaml
# Your code here

Need a hint?

Under the container spec, add resources: with limits: and set memory: "200Mi".

3

Apply the updated pod configuration

Run the command kubectl apply -f myapp-pod.yaml to update the pod with the new memory limits.

Kubernetes

kubectl get pods
kubectl describe pod myapp-pod

# Apply the updated pod configuration
# Your code here

Need a hint?

Use kubectl apply -f myapp-pod.yaml to update the pod with your changes.

4

Verify the pod is running without OOMKilled status

Run kubectl get pods and kubectl describe pod myapp-pod again to confirm the pod is running and the container status does not show OOMKilled.

Kubernetes

kubectl get pods
kubectl describe pod myapp-pod
# Check that OOMKilled is no longer in the container status
# Your code here

Need a hint?

Look for Status: Running and absence of OOMKilled in the container status.