CompTIA Cloud+ (CV0-004)DevOps FundamentalsHard
A development team wants the ability to instantly disable a newly released feature for all users if problems occur, without redeploying code or performing a full application rollback. Which technique should be implemented in the CI/CD pipeline?
- ABlue-green deployment
- BRolling update
- CFeature flag
- DImmutable infrastructure
Show answer & explanationAnswer & explanation
Correct answer: C. Feature flag
Feature flags allow specific features to be toggled on or off at runtime through configuration, enabling instant disabling of a problematic feature without any redeployment. Blue-green deployment, rolling updates, and immutable infrastructure all require some form of redeployment or environment switch to change behavior.
Why the other options are wrong
- A. Blue-green deployment requires switching entire environments, not simply toggling one feature off.
- B. Rolling updates gradually redeploy new instances, which still requires a deployment action.
- D. Immutable infrastructure requires replacing servers/images entirely rather than toggling a feature.
Feature Flag
A runtime configuration switch that enables or disables a specific application feature without requiring code redeployment.
- Allows instant rollback of a single feature
- Supports gradual feature rollout (feature flagging)
- Decouples deployment from feature release timing
Memory trick: A feature flag is a light switch on the wall you can flip off instantly, no rewiring needed.