Details
Major Description
I would like to consider un-deprecating the SecondaryNameNode for 0.23, and amending the documentation to indicate that it is still the most trust-worthy way to run checkpoints, and while CN/BN may have some advantages, they're not battle hardened as of yet. The test coverage for the 2NN is far superior to the CheckpointNode or BackupNode, and people have a lot more production experience. Indicating that it is deprecated before we have expanded test coverage of the CN/BN won't send the right message to our users. (For comparison, look at what a mess we got into by prematurely deprecating the "old" MR API before the "new" API had feature parity and a few versions of bug fixes).