Explanation
= The conditions are sufficient for Kubernetes to dynamically provision a persistentVolume, because a storageClass defines the provisioner and parameters for creating a volume on-demand. A persistentVolumeClaim that specifies a storageClass triggers the dynamic provisioning process, and Kubernetes will automatically create and bind a persistentVolume that matches the request. This eliminates the need for manual intervention by cluster administrators to provision storage volumes. References:
* Dynamic Volume Provisioning | Kubernetes
* Persistent volumes and dynamic provisioning | Google Kubernetes Engine ...
* Dynamic Provisioning and Storage Classes in Kubernetes

https://docs.docker.com/engine/reference/commandline/swarm/

Explanation
Deleting the /var/lib/docker directory will not upgrade Docker Engine CE to Docker Engine EE. It will only remove all the data stored by Docker, such as images, containers, volumes, and networks. This can cause data loss and disrupt the running services. To upgrade from Docker Engine CE to Docker Engine EE, you need to follow the official instructions from Docker, which involve uninstalling the CE package and installing the EE package. You also need to have a valid license to use Docker Engine EE. References:
* Upgrading Docker CE to EE for the Impatient - Part I
* Install Docker Engine
* Moving from docker ce to docker-EE - Stack Overflow

Explanation
= A persistentVolumeClaim (PVC) is a request for storage by a user. It is similar to a Pod. Pods consume node resources and PVCs consume PV resources1. A PVC can specify a storage class, which is a way of requesting a certain quality of service for the volume2. If the storage class is empty, it means the PVC does not have any specific storage class requirements and can be bound to any PV that satisfies its size and access mode3.
However, if there is no existing PV that matches the PVC's requirements, the PVC remains unbound until a suitable PV becomes available. This can happen either by manual provisioning by an administrator or by dynamic provisioning using StorageClasses1. References:
* Persistent Volumes | Kubernetes
* Storage Classes | Kubernetes
* Configure a Pod to Use a PersistentVolume for Storage | Kubernetes