What does Kubernetes use to manage the deployment of applications?

Kubernetes utilizes controllers to manage the deployment and lifecycle of applications. Controllers are key components within the Kubernetes architecture that continually monitor the state of the applications running in a cluster. They ensure that the current state of the system matches the desired state defined by the user. By doing this, controllers can perform tasks such as scaling applications up or down, rolling out updates, and maintaining the desired number of replicas. This ability to manage and adapt to changes in resources and application states is a fundamental aspect of Kubernetes, making controllers central to its operation.

In contrast, plugins extend the functionality of Kubernetes but do not directly manage application deployment. Services in Kubernetes facilitate networking and access to applications but are not responsible for the management processes. Handlers, while relevant in programming contexts, are not a specific component of Kubernetes for application management. Thus, the role of controllers in maintaining and optimizing deployments is what makes them the correct choice for this question.