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Hi Alan,
Thanks for your clarification, the way you suggested will solve my issue.
But i already have a netapp backend in my central site and to add another
backend should i follow this documentation:
https://access.redhat.com/documentation/en-us/red_hat_openstack_platform/17.0/html/custom_block_storage_back_end_deployment_guide/ref_configuration-sample-environment-file_custom-cinder-back-end

And should i remove the old netapp environment file and use the new custom
environment file created using the above mentioned guide??

I already have a prod workload in the currently deployed netapp and I do
not want to cause any issues in that netapp storage.


With regards,
Swogat Pradhan

On Tue, May 30, 2023 at 8:43 PM Alan Bishop <abishop at redhat.com> wrote:

>
>
> On Thu, May 25, 2023 at 9:39 PM Swogat Pradhan <swogatpradhan22 at gmail.com>
> wrote:
>
>> Hi Alan,
>> My netapp storage is located in edge site itself.
>> As the networks are routable my central site is able to reach the netapp
>> storage ip address (ping response is 30ms-40ms).
>> Let's say i included the netapp storage yaml in central site deployment
>> script (which is not recommended) and i am able to create the volumes as it
>> is reachable from controller nodes.
>> Will i be able to mount those volumes in edge site VM's?? And if i am
>> able to do so, then how will the data flow?? When storing something in the
>> netapp volume will the data flow through the central site controller and
>> get stored in the storage space?
>>
>
> A cinder-volume service running in the central site's controplane will be
> able to work with a netapp backend that's physically located at an edge
> site. The good news is the c-vol service will be HA because it will be
> controlled by pacemaker running on the controllers.
>
> In order for VMs at the edge site to access volumes on the netapp, you'll
> need to set the CinderNetappAvailabilityZone [1] to the edge site's AZ.
>
> [1]
> https://opendev.org/openstack/tripleo-heat-templates/src/branch/stable/wallaby/deployment/cinder/cinder-backend-netapp-puppet.yaml#L43
>
> To attach a netapp volume, nova-compute at the edge will interact with
> cinder-volume in the controlplane, and cinder-volume will in turn interact
> with the netapp. This will happen over central <=> edge network
> connections. Eventually, nova will directly connect to the netapp, so all
> traffic from the VM to the netapp will occur within the edge site. Data
> will not flow through the cinder-volume service, but there are restrictions
> and limitations:
> - Only that one edge site can access the netapp backend
> - If the central <=> edge network connection then you won't be able to
> attach or detach a netapp volume (but active connections will continue to
> work)
>
> Of course, there are operations where cinder services are in the data path
> (e.g. creating a volume from an image), but not when a VM is accessing a
> volume.
>
> Alan
>
>
>> With regards,
>> Swogat Pradhan
>>
>> On Fri, 26 May 2023, 10:03 am Alan Bishop, <abishop at redhat.com> wrote:
>>
>>>
>>>
>>> On Thu, May 25, 2023 at 12:09 AM Swogat Pradhan <
>>> swogatpradhan22 at gmail.com> wrote:
>>>
>>>> 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?
>>>>
>>>
>>> Where is the NetApp physically located? Tripleo's DCN architecture
>>> assumes the storage is physically located at the same site where the
>>> cinder-volume service will be deployed. If you include the
>>> cinder-netapp-storage.yaml environment file in the central site's
>>> controlplane, then VMs at the edge site will encounter the problems I
>>> outlined earlier (network latency, no ability to do cross-AZ attachments).
>>>
>>>
>>>> I believe it is not possible right?? as the cinder volume in the edge
>>>> won't have the config for the netapp.
>>>>
>>>
>>> The cinder-volume services at an edge site are meant to manage storage
>>> devices at that site. If the NetApp is at the edge site, ideally you'd
>>> include some variation of the cinder-netapp-storage.yaml environment file
>>> in the edge site's deployment. However, then you're faced with the fact
>>> that the NetApp driver doesn't support A/A, which is required for c-vol
>>> services running at edge sites (In case you're not familiar with these
>>> details, tripleo runs all cinder-volume services in active/passive mode
>>> under pacemaker on controllers in the controlplane. Thus, only a single
>>> instance runs at any time, and pacemaker provides HA by moving the service
>>> to another controller if the first one goes down. However, pacemaker is not
>>> available at edge sites, and so to get HA, multiple instances of the
>>> cinder-volume service run simultaneously on 3 nodes (A/A), using etcd as a
>>> Distributed Lock Manager (DLM) to coordinate things. But drivers must
>>> specifically support running A/A, and the NetApp driver does NOT.)
>>>
>>> Alan
>>>
>>>
>>>> With regards,
>>>> Swogat Pradhan
>>>>
>>>> On Thu, May 25, 2023 at 2:17 AM Alan Bishop <abishop at redhat.com> wrote:
>>>>
>>>>>
>>>>>
>>>>> On Wed, May 24, 2023 at 3:15 AM Swogat Pradhan <
>>>>> swogatpradhan22 at 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
>>>>>>
>>>>>
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