Hi Helix team, We have configured the Helix state model so that there can only be one master instance among the cluster participants. What is the recommended approach in Helix to allow only the master instance to edit a shared znode? We are trying to avoid split brain, i.e., many masters editing the same znode.
Looking at ZooKeeper features we have at least the following approaches: 1. Znode ACLs. Helix controller edits the ACL before electing new master. Only allow master node to edit the znode. 2. ZooKeeper session expiration: New master gets elected when old master's session expires. Old master can't make edits with an expired session. 3. Multi operation: Atomically check that node is still master and edit the znode. Does Helix provide any fencing mechanisms of its own? Best regards, Martin Yrjölä
