[DRBD-user] LINSTOR Satellite DRBD version check

[Robert Altnoeder]

On 11/30/18 2:25 PM, Roland Kammerer wrote:
> I don't think that is a good idea. Nobody starts up the satellite
> manually, it is started by systemd (or whatever flavor one prefers). And
> micro-packaging a linstor-satellite-drbd/linstor-satellite-nodrbd is a
> bad idea.

We'll figure out what alternatives there are and what the pros and cons are.

We could presumably run the check before attempting to deploy the first
resource that requires DRBD, and if the check failed, repeat the check
every time the DeviceManager retries the resource creation. Once the
check completes, it would not normally run again until the satellite is
restarted.

Another possibility would be to run the check whenever a DRBD-related
operation failed.

What I would like to avoid is running the check every time the
DeviceManager service modifies a resource, because since the check runs
an external command, it can potentially introduce high latency.

> The controller has all the knowledge whether a given satellite needs
> DRBD or not. And depending on that, the controller should initiate that
> check.


The Satellite should be able to do that autonomously on the Satellite
side with the information received from the Controller (storage pools,
specifically), that would avoid any additional processing load on the
Controller when it connects to Satellites.

br,
Robert