I also don't really know why you would need a single host being "preferred" as leader. I think the safest (and the best practice) is to make sure all your ZooKeeper servers are the same in terms of networking / performance / etc.
Not knowing your goals, maybe the Observer feature is also something you can take a look into: https://zookeeper.apache.org/doc/r3.6.3/zookeeperObservers.html Best regards, Mate On Mon, Jun 20, 2022 at 9:57 AM Enrico Olivelli <eolive...@gmail.com> wrote: > George, > really, it should not be a problem which is the leader. it is > automatically chosen. > Each node should be ideally as powerful as the other peers. > > why do you need this "preferred leader" ? > I am afraid that you have some flaw in your design > > Enrico > > Il giorno lun 20 giu 2022 alle ore 05:39 Kezhu Wang <kez...@gmail.com> > ha scritto: > > > > Hi, > > > > I think this could be achieved with help from `reconfig`[1]: > > * Configs all nodes with `standaloneEnabled=false`, > `reconfigEnabled=true`. > > * Starts node-2 as sole quorum participant. > > * Now node-2 is the leader. You will see "No server failure will be > > tolerated. You need at least 3 servers”. > > * Starts node-1 and node-3 with all quorum. > > * `zkCli.sh config` shows only node-2 for now. > > * `zkCli.sh reconfig -add node-1,node-2` will add both node-1, node-3 to > > quorum. > > * According to `Leader.tryToCommit`[2], node-2 will be the leader due to > > old leadership in old quorum and voter in new quorum. > > > > node-2 is the leader in whole progress. > > > > [1]: https://zookeeper.apache.org/doc/current/zookeeperReconfig.html > > [2]: > > > https://github.com/apache/zookeeper/blob/b4f9aab099880ba8ef08eaff697debe6cdeae057/zookeeper-server/src/main/java/org/apache/zookeeper/server/quorum/Leader.java#L950 > > > > Best, > > Kezhu Wang > > > > On June 19, 2022 at 23:00:59, Heller, George A III CTR (USA) ( > > george.a.heller2....@mail.mil.invalid) wrote: > > > > We have 3 Zookeeper nodes and would like node 2 to always be the leader > > unless node 2 goes down. IF node 2 goes down, then either node 1 or node > 3 > > would be the leader. > > > > > > > > Can this be done? If so, how would this be done? >
