What resources in Kubernetes are necessary to deploy an application?

The following main resources are usually defined for deploying an application in Kubernetes:

• Pod — the smallest deployable unit containing one or more containers.
• Deployment — manages the creation and updating of Pods, providing declarative updates to applications.
• Service — provides stable network access to Pods, load balancing.
• ConfigMap and Secret — for passing configuration data and secrets to containers.
• PersistentVolumeClaim (PVC) — for attaching persistent storage to Pods.

Most often, a Deployment is created to manage the lifecycle of Pods and a Service for access. Additionally, ConfigMap, Secret, and PVC may be used depending on the application's requirements.