Major Description
Spark has a hardcode list to contain known shuffle managers, which has two values now. It does not contain user's custom shuffle manager which is set through Spark config "spark.shuffle.manager".
We hit issue when set "spark.shuffle.manager" with our own shuffle manager plugin (Uber Remote Shuffle Service implementation, https://github.com/uber/RemoteShuffleService). Other users will hit same issue when they implement their own shuffle manager.
Need to add "spark.shuffle.manager" config value to the known managers list as well.
The know managers list is in code:
common/network-shuffle/src/main/java/org/apache/spark/network/shuffle/ExternalShuffleBlockResolver.java
private final List<String> knownManagers = Arrays.asList(
"org.apache.spark.shuffle.sort.SortShuffleManager",
"org.apache.spark.shuffle.unsafe.UnsafeShuffleManager");
