To horizontally scale a Tanzu Kubernetes cluster, the worker node count must be increased or decreased. This involves adjusting the number of worker nodes that are available to handle workloads, effectively distributing the load and improving performance as needed.

The Tanzu Kubernetes Grid Service supports Antrea and Calico as the container network interfaces (CNIs) for Tanzu Kubernetes clusters. This knowledge is based on VMware's official documentation, which specifies that Antrea and Calico are the supported CNIs for Tanzu Kubernetes clusters created by the Tanzu Kubernetes Grid Service.

Virtual machine images used to deploy Tanzu Kubernetes clusters are stored in the Content Library. The Content Library is a feature in VMware that allows users to store and manage VM templates, ISO images, and scripts, making it the suitable storage for VM images in this context.

Persistent volumes provide the capability to retain application state and data for containerized applications. Unlike ephemeral storage, which is temporary and tied to the lifecycle of a container, persistent volumes ensure that data is preserved across pod restarts and re-deployments. This retention is crucial for applications that need to maintain state, such as databases and stateful services.

The correct way to delete a Persistent Volume Claim is by using the kubectl delete persistentvolumeclaim command. This command is specifically designed for managing Kubernetes resources, including Persistent Volume Claims, and follows the proper protocol for deletion within a Kubernetes environment.