“Brittle” means that if the node fails, your cluster cannot change until the node is back up. Single point of failure.
The whole point of Zookeeper is redundant protection against failure. So running a single Zookeeper node is just wrong. A Zookeeper ensemble needs to be an odd number of instances, because they will do majority voting. Three or five is a good number. Three works with one failure. Five works with one failure while you are upgrading the Zookeeper ensemble. We run a three node ensemble in test and a five node ensemble in prod. wunder Walter Underwood wun...@wunderwood.org http://observer.wunderwood.org/ (my blog) > On Feb 27, 2017, at 4:57 PM, Mike Thomsen <mikerthom...@gmail.com> wrote: > > It's a brittle ZK configuration. A typical ZK quorum is three nodes for > most production systems. One is fine, though, for development provided the > system it's on is not overloaded. > > On Mon, Feb 27, 2017 at 6:43 PM, Rick Leir <rl...@leirtech.com> wrote: > >> Hi Mike >> We are using a single ZK node, I think. What problems should we expect? >> Thanks -- Rick >> -- >> Sent from my Android device with K-9 Mail. Please excuse my brevity.
