Open Stack

Hi Alan,
If you please could help me clarify this.

With regards,
Swogat Pradhan

On Fri, 26 May 2023, 10:09 am 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?
>
> 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
>>>>>
>>>>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.openstack.org/pipermail/openstack-discuss/attachments/20230528/16e2b03c/attachment.htm>