> On July 29, 2020, 3:27 p.m., Qian Zhang wrote:
> > src/slave/csi_server.cpp
> > Lines 244-245 (patched)
> > <https://reviews.apache.org/r/72716/diff/2/?file=2236468#file2236468line244>
> >
> >     Do we have to use `started` and `initializationCallbacks`? Can we do 
> > the similar with 
> > https://github.com/apache/mesos/blob/1.10.0/src/csi/v1_volume_manager.cpp#L1336
> >  ?
> 
> Greg Mann wrote:
>     The reason it's more complicated here is because we may add more 
> "initialization logic" after server construction if publish/unpublish calls 
> are made before the server is started. So we need an approach which will 
> allow us to add more function calls which are executed during startup. I 
> explored another approach while coding but this is what I ended up settling 
> on, but I'm happy to explore other options if we can think of something 
> better.
> 
> Qian Zhang wrote:
>     I see currently you put the "initialization logic" (i.e. generate auth 
> token and intialize plugins) in the constructor of `CSIServerProcess`. Can we 
> instead do that in `CSIServerProcess::start()` and do the following in 
> `CSIServer::start()`.
>     ```
>     Future<Nothing> CSIServer::start()
>     {
>       started = process::dispatch(process.get(), &CSIServerProcess::start);
>       return started;
>     }
>     ```
>     
>     And then in `CSIServer::publishVolume` and `CSIServer::unpublishVolume` 
> we could do the following:
>     ```
>     Future<string> CSIServer::publishVolume(
>         const Volume::Source::CSIVolume& volume)
>     {
>       return started
>         .then(process::defer(
>           process.get(),
>           &CSIServerProcess::publishVolume,
>           volume));
>     }
>     ```
>     So any publish and unpublish volume calls can only be executed after CSI 
> server is started. HDYT?
> 
> Greg Mann wrote:
>     The reason I didn't follow this approach is that it doesn't guarantee 
> that the order of publish/unpublish calls would be maintained when 
> initializing, but maybe that's OK?
>     
>     I think that in our current implementation of `Future` in libprocess the 
> order would be maintained, but this isn't guaranteed by the interface. Am I 
> being too paranoid here? :-)
> 
> Qian Zhang wrote:
>     > it doesn't guarantee that the order of publish/unpublish calls would be 
> maintained when initializing
>     
>     Could you please elaborate a bit why this is a problem? In volume 
> manager, I see we already have a sequence per volume to make sure all CSI 
> gRPC calls on the same volume are processed in a sequential order.

Let's say the containerizer cleans up two orphan containers during recovery, 
'containerA' and 'containerB', and the csi isolator ends up calling 
`csiManager->unnPublish(pluginName, volumeForContainerA);` and then 
`csiManager->unPublish(pluginName, volumeForContainerB);`. At this point, the 
interface offered by the `Future` class does not guarantee that the 
continuation associated with the first `unPublish()` call will be executed 
before the continuation for the second `unPublish()` call. Does that make sense?


- Greg


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On Aug. 3, 2020, 6:58 p.m., Greg Mann wrote:
> 
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> https://reviews.apache.org/r/72716/
> -----------------------------------------------------------
> 
> (Updated Aug. 3, 2020, 6:58 p.m.)
> 
> 
> Review request for mesos, Andrei Budnik and Qian Zhang.
> 
> 
> Bugs: MESOS-10163
>     https://issues.apache.org/jira/browse/MESOS-10163
> 
> 
> Repository: mesos
> 
> 
> Description
> -------
> 
> Added implementation of the CSI server.
> 
> 
> Diffs
> -----
> 
>   src/CMakeLists.txt 4e15e3d99aa2cce2403fe07e762fef2fb4a27dea 
>   src/Makefile.am 447db323875e4cad46000977f4a61600baff8f89 
>   src/slave/csi_server.cpp PRE-CREATION 
> 
> 
> Diff: https://reviews.apache.org/r/72716/diff/4/
> 
> 
> Testing
> -------
> 
> Details at the end of this chain.
> 
> 
> Thanks,
> 
> Greg Mann
> 
>

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