Organizing with recommended labels in Kubernetes - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Purpose of the 'app.kubernetes.io/name' label

What is the main purpose of using the app.kubernetes.io/name label in Kubernetes resource manifests?

A To uniquely identify the name of the application across resources

B To specify the version of the application deployed

C To indicate the environment like production or staging

D To define the owner or team responsible for the resource

💡 Hint

Think about how you would find all resources belonging to the same application.

The app.kubernetes.io/name label is used to uniquely identify the application name. This helps group and select resources that belong to the same app.

💻 Command Output

intermediate

Output of label selector command

Given the following Kubernetes pods with labels:

pod1: app.kubernetes.io/name=frontend, app.kubernetes.io/version=1.0
pod2: app.kubernetes.io/name=backend, app.kubernetes.io/version=1.0
pod3: app.kubernetes.io/name=frontend, app.kubernetes.io/version=2.0

What is the output of the command kubectl get pods -l app.kubernetes.io/name=frontend?

A Only pod3 is listed

B pod1, pod2, and pod3 are listed

C Only pod1 is listed

D pod1 and pod3 are listed

💡 Hint

The label selector matches all pods with the specified label key and value.

The selector app.kubernetes.io/name=frontend matches both pod1 and pod3 because they share that label, regardless of version.

❓ Configuration

advanced

Correct label usage in Deployment manifest

Which option shows the correct way to add recommended labels to a Kubernetes Deployment manifest for an app named myapp version v2 owned by team devops?

A

metadata:
  labels:
    app.kubernetes.io/name: myapp
    app.kubernetes.io/version: v2
    app.kubernetes.io/managed-by: devops

B

metadata:
  labels:
    app.kubernetes.io/name: myapp
    app.kubernetes.io/version: v2
    app.kubernetes.io/part-of: devops

C

metadata:
  labels:
    app.kubernetes.io/name: myapp
    app.kubernetes.io/version: v2
    app.kubernetes.io/created-by: devops

D

metadata:
  labels:
    app.kubernetes.io/name: myapp
    app.kubernetes.io/version: v2
    app.kubernetes.io/owner: devops

💡 Hint

Check the official recommended labels for grouping and ownership.

The label app.kubernetes.io/part-of is used to indicate the higher-level group or team the app belongs to. managed-by, created-by, and owner are not standard recommended labels.

❓ Troubleshoot

advanced

Why does label selector fail to find pods?

You run kubectl get pods -l app.kubernetes.io/part-of=frontend but no pods are returned. You know pods exist with label app.kubernetes.io/part-of: frontend. What is the most likely cause?

A The label value in pods is uppercase <code>Frontend</code> instead of lowercase <code>frontend</code>

B The pods do not have the label <code>app.kubernetes.io/part-of</code>

C The pods are in a different namespace than the current kubectl context

D The label key is misspelled in the selector

💡 Hint

Label selectors only find resources in the current namespace by default.

By default, kubectl get pods -l searches only the current namespace. If pods with the label exist in another namespace, they won't be listed unless you specify --all-namespaces or switch namespaces.

✅ Best Practice

expert

Recommended label for tracking deployment instance

Which recommended Kubernetes label should you use to uniquely identify a specific deployment or release instance of an application?

A app.kubernetes.io/instance

B app.kubernetes.io/component

C app.kubernetes.io/managed-by

D app.kubernetes.io/version

💡 Hint

This label helps distinguish different deployments of the same app version.

The app.kubernetes.io/instance label is used to uniquely identify a deployment or release instance of an application, useful when multiple instances of the same app/version run.