Open Stack

Hello everyone,

I have cinder installed on my controller node, can anyone explain to me 
how a VM becomes aware of the volume ?

After all a VM is launched on a node different than the controller one 
so if the VM wants to store something on the Volume, does it have to 
send the data to the controller node which in his turn will save the 
data on the volume using cinder or is there a direct connection between 
the VM and the volume after allocation, if yes, is this connection on 
the hypervisor level or what level exaclty?

Thanks, really appreciate it if you can help me out there !

Best regards
Fellow Stacker