Thanks for correcting me on the dynamic consensus membership change. Looks like the basic support was indeed there, but several important enhancements were needed (for correctness and usability).
- To make the "online" piece of the membership change work correctly we added support for LEARNER (PRE VOTER) role (where the new member enters in a non-voting mode till it's caught up). https://github.com/YugaByte/yugabyte-db/commit/909d26e31ecd0....
- Load Balancing (which uses the membership changes) is automatic. (https://github.com/YugaByte/yugabyte-db/commit/e4667eb7ec0e6...)
- Remote bootstrap (due to membership changes) also has undergone substantial changes given that YugaByte DB uses a customize/extended version of RocksDB as the storage engine and does a tighter coupling of Raft with RocksDB storage engine. (https://github.com/YugaByte/yugabyte-db/blob/master/docs/ext...)
- Dynamic Leader Balancing is also new-- it causes leadership to be proactively altered in a running system to ensure each node is the leader for a similar number of tablets.
regards, Kannan