Certified Kubernetes Application Developer (CKAD) Practice Test

The correct method to apply a configuration change to a Kubernetes resource is by using the command `kubectl apply -f <config-file>.yaml`. This command orchestrates the deployment of changes specified in the configuration file to the Kubernetes cluster.

When you use `kubectl apply`, Kubernetes handles the process of determining what changes need to be made to the existing resource. It performs a three-way merge of the existing live configuration, the last-applied configuration, and the new configuration defined in the specified file. This enables Kubernetes to understand both what has changed and what needs to be updated, making it the most efficient and effective way to manage configurations.

Additionally, this command is idempotent, meaning that if you apply the same configuration multiple times, it will not result in unintended changes, as Kubernetes will only make updates if there are actual differences.

This aspect of the command makes it suitable for continuous integration and deployment processes, as it allows developers to manage and evolve their application configurations seamlessly without disruptions.