--sync_nodes=false gives user flexibility to add/remove nodes in the
cluster using REST api/kubectl cli and at the same time can use
cloud provider for other resources like persistent disks, etc.
During startup, if nodes have already been defined the controller
does not need to create them, just needs to keep them up to date.
When defining a static list, the controller would loop and fail
repeatedly if the node existed.
I don't know if we need to update the node during registration,
as long as the sync loop checks it later.
