Dynamic Cluster Membership about openraft HOT 5 CLOSED

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from openraft.

You have initialized the cluster twice with different config, which result in a brain split state.

To incrementally setup a cluster, just call Raft::initialize({0:BasicNode}) on node-0.
Then call Raft::add_learner({1:BasicNode}) on node-0 to add node-1 to the cluster.
Then call Raft::change_membership(...) to make node-1 a voter.

Or setup a cluster in oneshot: call Raft:initialize({0:BasicNode, 1:BasicNode...}) on node-0;

Refer to:
https://docs.rs/openraft/latest/openraft/docs/faq/index.html#how-to-initialize-a-cluster

from openraft.

@drmingdrmer First off, thank you for being so responsive :)

Also, I saw your conversation on Discord with diptanuc - that helped quite a bit.

However, my only point of confusion is that if I want to start two nodesindependently of one another - seed_node (node 0) and node 1, how do I start them? The independently is important to me here

I can start node 0 using initialize but then how do I start node 1 in a way that does not cause brain split and allow node 1 to communicate with node 0 to allow itself to be registered as part of the cluster?

All the examples I've seen just use add_learner on the seed node to add a new node assuming that the seed node already knows what nodes it wants to add. But what do I do if I want nodes to be able to start independently of the seed node and then send a message to the seed node to allow themselves to be discovered?

from openraft.

First of all, IMHO, two independent nodes just means brain split. They are equivalent concept, because these two nodes can propose different logs and there is no consensus between them.

Because they have different data, you can not add node-1 with non-empty data(i.e., node-1 has already proposed logs and applied) to the seed node node-0 without losing node-1's data.

If what you want is to let seed node-0 to discover another empty node to join into the cluster, it is not about Raft.
There should be registry service let node-1 to register itself and so that seed node-0 will discover such candidate nodes.

from openraft.

Closing this issue.

@redixhumayun
If you have any further question, please feel free to reopen it:)

from openraft.