[DRBD-user] Why to specify node type?

[kvaps]

Hi, I still not get in why do we need to create special types of nodes
in linstor, and do we need it?

As can I see linstor supports next types of the nodes:

 - Controller
 - Auxiliary
 - Combined
 - Satellite

As can I see following the official documentation, there is written
that you have to create special Controller node in the Linstor for the
Proxmox plugin, and Combined node for the OpenStack's Cinder.

My question is why do we need to specify Controller as a node if
everything can work and without this.

Why Auxiliary node type is needed for?

Thank you in advance!

- kvaps