Single node event triggering

[hashicorp]

Single node event triggering

[mitchellh]

This orchestration of who does what is difficult from a Serf core perspective because there is no "ack" functionality yet for events. We've talked about it. I think that is the core thing needed here and I think it would be possible, but it would be dependent on that.

Other than that, there is no way to do this unless you put this "single node" coordination within your event handlers yourself. i.e. "your problem"

Thoughts, @armon?

[armon]

I think the issue is that having only a single node handle it requires a concensus algorithm. The reason is that you can think of the problem as needing to either elect a single leader to perform the action or you are acquiring a global mutex. In either case, we need some stronger consistency to support this. That said, I think this is something we want to support as well! No easy answers, but something we need to look at.

[zslayton]

@mitchellh, @armon -- That makes complete sense, thank you for your replies.

[crshovrd]

Since Serf doesn't support distributed locking yet, a work around I have is to use NFS and use the OS to help acquire a lock.

In the event that you need a better distributed locking mechanism, I suggest looking into Zookeeper.

[armon]

Serf's goal is to provide an available and network partition tolerant solution. As such, any features that require strong consistency are out of scope. Instead it makes sense to use Serf along side other tools that can provide strong consistency.