Hello Ratis community, I am trying to understand what is the proper way to initialize a Ratis group. My expectation is that the group itself should maintain the list of peers through configuration changes and the raft log, and thus setting the list of peers is required only during the initial group setup. However, what I observe in tests is that the initial list of peers passed to addGroup request is restored only when the corresponding configuration change has been committed by Ratis. More specifically, I see the following behavior: * Create a Raft server S1, initialize a group G1 [peers: S1. S2]. I get a reply that the group was successfully added, but the configuration change is not committed because S2 does not exist and thus no leader can be elected * I stop the server S1 and then restart it with RECOVERY startup option. The group G1 is restored, but it is restored with the empty peers list
I was wondering whether this is an expected behavior? I fully understand that subsequent configuration changes must go through regular raft protocol, but I would expect that the initial configuration setup is 'committed' unconditionally and can be reset with the FORMAT startup option if required. If this is an expected behavior, I was wondering what is the suggested way to do the initial group setup? The potential issue I have in mind is as follows: let's say I am setting up a 3-node cluster with a proper initial configuration, and addGroup request succeeds on all nodes, but shortly after one of the nodes gets disconnected and restarted. The two remaining nodes will be able to commit the proposed configuration, however, the third node will restart with an empty peers list, so it will require another addGroup request to join the cluster. Or am I missing something? Thank you, Alexey
