This repository houses community-maintained external provisioners plus a helper library for building them. Each provisioner is contained in its own directory so for information on how to use one, enter its directory and read its documentation. The library is contained in the lib directory.
An external provisioner is a dynamic PV provisioner whose code lives out-of-tree/external to Kubernetes. Unlike in-tree dynamic provisioners that run as part of the Kubernetes controller manager, external ones can be deployed & updated independently.
External provisioners work just like in-tree dynamic PV provisioners. A StorageClass object can specify an external provisioner instance to be its provisioner like it can in-tree provisioners. The instance will then watch for PersistentVolumeClaims that ask for the StorageClass and automatically create PersistentVolumes for them. For more information on how dynamic provisioning works, see the docs or this blog post.
import (
"github.com/kubernetes-incubator/nfs-provisioner/lib/controller"
)You need to implement the Provisioner interface then pass your implementation to a ProvisionController and run the controller. The controller takes care of deciding when to call your implementation's Provision or Delete. The interface and controller are defined in the above package.
Note that because your provisioner needs to depend also on client-go and the library itself depends on a specific version of client-go, to avoid a dependency conflict you must ensure you use the exact same version of client-go as the library.
For a full guide on how to write an external provisioner using the library that demonstrates the above, see here.
If you want your provisioner to be compatible with users' RBAC/PSP/OpenShift authorization policies also consider reading this.