spec: https://review.opendev.org/#/c/650188/
Agreements from the room[1]: * new config option 'using_shared_disk_provider' (just an example name) on the compute level to ignore the DISK_GB reporting from the driver * new config option 'sharing_disk_aggregate' (just an example name) on the compute level to tell nova compute what is the UUID of the placement aggregate that contains the sharing DISK_GB providers in placement. * the "using_shared_disk_provider" flag necessarly has to be explicit since if not, it would be a chicken-and-egg problem on a greenfields install as the shared RP wouldn't be created * deployer needs to create the sharing disk RP and report inventory / traits on it * deployer needs to define the placement aggregate and add the sharing disk RP into it * when compute restarts and sees that 'using_shared_disk_provider' = True in the config, it adds the its compute RP to the aggregate defined in 'sharing_disk_aggregate' Then if it sees that the root RP still has DISK_GB inventory then trigger a reshape * os-hypervisor API response (in a new microversion) will have a link to the sharing disk RP if the compute is so configured.
TODO: * tpatil to update the spec