The _dynk8s-provisioner_ only needs writable storage to store copies of
the AWS SNS notifications it receives for debugging purposes. We don't
need to keep these around indefinitely, so using ephemeral node-local
storage is sufficient. I actually want to get rid of that "feature"
anyway...
I guess I thought `defaultBackend` was scoped to the TLS host, but it
appears to be global, across all Ingress resources in the cluster.
Thus, it really doesn't make any sense for any Ingress to have a default
backend, and certainly not the dynk8s provisioner.