Hi Alan,
So, can I include the cinder-netapp-storage.yaml file in the central site and then use the new backend to add storage to edge VM's?
I believe it is not possible right?? as the cinder volume in the edge won't have the config for the netapp.

With regards,
Swogat Pradhan

On Thu, May 25, 2023 at 2:17 AM Alan Bishop <abishop@redhat.com> wrote:


On Wed, May 24, 2023 at 3:15 AM Swogat Pradhan <swogatpradhan22@gmail.com> wrote:
Hi,
I have a DCN setup and there is a requirement to use a netapp storage device in one of the edge sites.
Can someone please confirm if it is possible?

I see from prior email to this list that you're using tripleo, so I'll respond with that in mind.

There are many factors that come into play, but I suspect the short answer to your question is no.

Tripleo's DCN architecture requires the cinder-volume service running at edge sites to run in active-active
mode, where there are separate instances running on three nodes in to for the service to be highly
available (HA).The problem is that only a small number of cinder drivers support running A/A, and NetApp's
drivers do not support A/A.

It's conceivable you could create a custom tripleo role that deploys just a single node running cinder-volume
with a NetApp backend, but it wouldn't be HA.

It's also conceivable you could locate the NetApp system in the central site's controlplane, but there are
extremely difficult constraints you'd need to overcome:
- Network latency between the central and edge sites would mean the disk performance would be bad.
- You'd be limited to using iSCSI (FC wouldn't work)
- Tripleo disables cross-AZ attachments, so the only way for an edge site to access a NetApp volume
would be to configure the cinder-volume service running in the controlplane with a backend availability
zone set to the edge site's AZ. You mentioned the NetApp is needed "in one of the edge sites," but in
reality the NetApp would be available in one, AND ONLY ONE edge site, and it would also not be available
to any instances running in the central site.

Alan
 
And if so then should i add the parameters in the edge deployment script or the central deployment script.
Any suggestions?

With regards,
Swogat Pradhan