[SPARK-26380] ExternalShuffleBlockResolver should not block shuffle managers by name.

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Incomplete
• Affects Version/s: 2.3.2
• Component/s: Shuffle, Spark Core
• Labels: bulk-closed
• Assignee: Unassigned
• Reporter: Peiyu Zhuang
• Created: 17/Dec/18 08:24
• Updated: 25/May/21 01:49
• Resolved: 25/May/21 01:39

Description

We configure a shuffle manager that is compatible with the original Spark shuffle manager (but with other network/storage implementation) in our environment.  It doesn't require any modification to Spark source code and It works fine until we enable dynamic allocation.  The problem is that in ExternalShuffleBlockResolver class it checks the name of the shuffle manager class and raise an UnsupportedOperationException if shuffle manager is not SortShuffleManager or UnsafeShuffleManager.
Since shuffle manager is totally configurable, I think user should be able to decide which shuffle manager to use when dynamic allocation is enabled.
Maybe we could change UnsupportedOperationException to a warning log telling user that the shuffle manager they are using may not be compatible with dynamic allocation and give them detail reasons why. On the other hand, user may still choose to use their own shuffle manager while knowing the risk behind it.