surahman commented on pull request #3725:
URL: https://github.com/apache/incubator-heron/pull/3725#issuecomment-965805550


   > One potential issue or design consideration... it seems to only make a 
single PVC for the entire topology. I was assuming it would be a PVC per pod. 
Here is the naming convention from the [Spark 
code](https://github.com/apache/spark/blob/de59e01aa4853ef951da080c0d1908d53d133ebe/resource-managers/kubernetes/core/src/main/scala/org/apache/spark/deploy/k8s/features/MountVolumesFeatureStep.scala#L76).
 It seems they have an index `$i` on the end as they loop through?
   
   The design is such that a single PVC is generated per dynamically 
allocated/backed volume for the entire `StatefulSet`. All of the `executor` 
pods will gain entries added for the `Volume Mounts` and the entire pod 
template will receive an entry for the shared `Volume`. Since it is a shared 
`Volume` for the `StatefulSet`, my assumption being this is to support amongst 
many other things, a shared disk between support containers makes perfect 
sense. You may allocate as many PVCs as you want for topology, though.
   


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