[Question] Clarification about starting a single-node cluster with raft-non-voter=true

[wellescastro]

Hi! I noticed that if I start a single-node cluster with raft-non-voter=true, the cluster starts appropriately electing the very same node, while I expect it not to work since I'm telling that the node is not a voter. Do you know if this is expected? Is it the 'raft-non-voter' argument being ignored since it would mean an invalid scenario?

This is what I executed in my machine:
.\rqlited.exe -node-id "testDatabase1" -http-addr "127.0.0.1:9501" -raft-addr "127.0.0.1:9502" -raft-non-voter=true testDatabase1

[otoolep]

That's interesting, I would need to check. I don't think I've ever tested that scenario (since it shouldn't really be sensible). I can check in a few days, as I'm traveling at the moment.

[otoolep]

I looked at the code to refresh my memory.

Operating as a "read-only node" (non-voting) is a cluster-joining -time thing. If you're not joining a cluster, and have no pre-existing state, the raft-non-voter is ignored and the node comes up as a single-node system. You weren't far off with your guess, it's just the parameter is ignored "by accident" when launching a single node.

I think this is confusing, and if someone tries to launch a single-node system from scratch, but with -raft-non-voter=true they are almost certainly confused. I'm going to change the code and have rqlited exit if asked to start in this meaningless configuration.

[otoolep]

I looked at the code to refresh my memory.

Operating as a "read-only node" (non-voting) is a cluster-joining -time thing. If you're not joining a cluster, and have no pre-existing state, the raft-non-voter is ignored and the node comes up as a single-node system. You weren't far off with your guess, it's just the parameter is ignored "by accident" when launching a single node.

I think this is confusing, and if someone tries to launch a single-node system from scratch, but with -raft-non-voter=true they are almost certainly confused. I'm going to change the code and have rqlited exit if asked to start in this meaningless configuration.

[otoolep]

I looked at the code to refresh my memory.

Operating as a "read-only node" (non-voting) is a cluster-joining -time thing. If you're not joining a cluster, and have no pre-existing state, the raft-non-voter is ignored and the node comes up as a single-node system. You weren't far off with your guess, it's just the parameter is ignored "by accident" when launching a single node.

I think this is confusing, and if someone tries to launch a single-node system from scratch, but with -raft-non-voter=true they are almost certainly confused. I'm going to change the code and have rqlited exit if asked to start in this meaningless configuration.

[wellescastro]

Oh ok, thanks for the enlightenment.

I think this is confusing, and if someone tries to launch a single-node system from scratch, but with -raft-non-voter=true they are almost certainly confused. I'm going to change the code and have rqlited exit if asked to start in this meaningless configuration.

I believe the change makes sense. Since I opened this issue just as a question, should I close it? thanks one more time.

[otoolep]

I'll close it once I make the code change.

[otoolep]

rqlited will now exit with this error if an attempt is made to launch a brand-new, standalone node, which isn't also instructed to join an existing cluster:

[rqlited] 2023/03/27 10:03:00 clustering failure: cannot create a new non-voting node without joining it to an existing cluster

[otoolep]

I don't think this issue warrants an immediate release, so the change will be in the next release.

Thanks for your help improving rqlite.

[wellescastro]

That's great, my pleasure. Thanks for quickly tackling this case.