Should leader automatically commit a uniform membership if the last config is a joint config?

[drmingdrmer]

If a 2-phase membership change did not finish, i.e., a joint config is left in raft log.
Should a new leader detect this and commit a uniform membership config?

• Pros: Auto commit uniform config will leave a clean env for user. This is what the etcd-raft does.

• Cons: joint config is not actually special at all. Not treat it as a special case just generalize raft algo: it can be used to setup a two-DC cluster: [{a,b,c}, {x,y,z}] and a quorum is union of all majority in every DC, e.g. [{a,b}, {y,z}] is a quorum. Further more, in a three-DC cluster, it impl a hierarchical quorum, just like zookeeper does.