kubectl apply vs create in Kubernetes - Practice Questions

Challenge - 5 Problems

🧠 Conceptual

intermediate

Difference in behavior between kubectl create and kubectl apply

What happens if you run kubectl create on a resource that already exists in the cluster?

A It updates the existing resource with new changes.

B It deletes the old resource and creates a new one.

C It ignores the command and does nothing.

D It throws an error saying the resource already exists.

💡 Hint

Think about whether kubectl create is designed to add new resources or modify existing ones.

kubectl create is used to add new resources. If the resource already exists, it will not update it but instead return an error.

🧠 Conceptual

intermediate

Effect of kubectl apply on existing resources

What does kubectl apply do when the resource already exists in the cluster?

A It deletes the existing resource and creates a new one.

B It throws an error saying the resource already exists.

C It updates the existing resource with the changes from the configuration file.

D It ignores the changes and leaves the resource as is.

💡 Hint

Consider how kubectl apply helps keep resources in sync with configuration files.

kubectl apply updates existing resources by applying the changes from the configuration file, allowing incremental updates.

💻 Command Output

advanced

Output of kubectl create on existing resource

What is the output when you run kubectl create -f pod.yaml if the pod already exists?

Kubernetes

kubectl create -f pod.yaml

A error: pods "mypod" already exists

B pod/mypod created

C pod/mypod configured

D Warning: pod/mypod already exists, skipping creation

💡 Hint

Remember that kubectl create does not update existing resources.

When the resource exists, kubectl create returns an error indicating the resource already exists.

💻 Command Output

advanced

Output of kubectl apply on existing resource

What is the output when you run kubectl apply -f deployment.yaml if the deployment already exists and is updated?

Kubernetes

kubectl apply -f deployment.yaml

A deployment.apps/mydeployment configured

B deployment.apps/mydeployment unchanged

C error: deployment.apps "mydeployment" already exists

D deployment.apps/mydeployment created

💡 Hint

Think about how kubectl apply reports changes.

kubectl apply reports configured when it updates an existing resource.

✅ Best Practice

expert

Choosing between kubectl create and apply in CI/CD pipelines

In a continuous deployment pipeline, which command is best to use to ensure the cluster matches the desired state defined in configuration files?

A kubectl get, to verify resources before deployment.

B kubectl apply, because it can create or update resources to match the config files.

C kubectl delete followed by kubectl create, to always start fresh.

D kubectl create, because it ensures resources are only created once.

💡 Hint

Consider which command helps keep resources in sync with config files automatically.

kubectl apply is preferred in CI/CD because it can create new resources or update existing ones, ensuring the cluster matches the desired state.