Feature flags in Kubernetes - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

What is the primary purpose of feature flags in Kubernetes?

Feature flags are used in Kubernetes to:

A Increase the CPU and memory limits of pods dynamically

B Automatically scale pods based on network traffic

C Control the rollout of new features without redeploying the entire application

D Encrypt data stored in Kubernetes secrets

💡 Hint

Think about how you can enable or disable features without changing the app code or redeploying.

Feature flags allow toggling features on or off dynamically, enabling safer rollouts and testing without full redeployment.

💻 Command Output

intermediate

What is the output of this kubectl command?

Given a ConfigMap named feature-flags with a key newUI set to true, what does this command output?

kubectl get configmap feature-flags -o jsonpath='{.data.newUI}'

A false

B Error: configmap not found

C null

D true

💡 Hint

Check the key value inside the ConfigMap data field.

The command extracts the value of the newUI key from the ConfigMap data, which is true.

❓ Configuration

advanced

Which YAML snippet correctly defines a ConfigMap for feature flags with 'betaFeature' enabled?

Select the valid Kubernetes ConfigMap YAML that sets a feature flag betaFeature to enabled.

A

apiVersion: v1
kind: ConfigMap
metadata:
  name: feature-flags
data:
  - betaFeature: enabled

B

apiVersion: v1
kind: ConfigMap
metadata:
  name: feature-flags
data:
  betaFeature: enabled

C

apiVersion: v1
kind: ConfigMap
metadata:
  name: feature-flags
features:
  betaFeature: enabled

D

apiVersion: v1
kind: ConfigMap
metadata:
  name: feature-flags
spec:
  betaFeature: enabled

💡 Hint

ConfigMap data must be under the data field as key-value pairs.

Option B correctly uses the data field with key-value pairs. Other options misuse fields or structure.

🔀 Workflow

advanced

What is the correct sequence to update a feature flag in a running Kubernetes cluster?

Put these steps in the correct order to update a feature flag stored in a ConfigMap:

A 1,4,2,3

B 4,1,3,2

C 1,2,4,3

D 2,1,4,3

💡 Hint

Think about editing first, then saving, verifying, and finally ensuring pods use the new config.

You first edit the ConfigMap, save changes, verify the update, then ensure pods reload the new config.

❓ Troubleshoot

expert

Why might a pod not reflect a changed feature flag in a ConfigMap immediately?

You updated a feature flag in a ConfigMap, but the pod still behaves as if the old flag is active. What is the most likely reason?

A The pod has not been restarted or does not watch for ConfigMap changes

B The ConfigMap was deleted accidentally

C The feature flag key was misspelled in the ConfigMap

D The pod's CPU limit is too low to apply changes

💡 Hint

Consider how pods get updated ConfigMap data during runtime.

Pods do not automatically reload ConfigMap changes unless they watch for updates or are restarted.