Since configuration info is stored in a znode, you could access it using a simple get operation. The getconfig operation is basically doing just that. So if you have a 3.5 server and a 3.4 client, the client should be able to read the list of servers and get notified when the list changes by setting a watch.
The 3.5 client has an updateServerList operation, which allows to create a zk handle with one list and later update the list. Thanks, Alex On Thu, Jan 5, 2017 at 12:41 PM, Shawn Heisey <[email protected]> wrote: > On 1/5/2017 11:19 AM, Washko, Daniel wrote: > > Thanks for the reply Shawn. I would like to clarify something though. > > Right now, the Dynamic Reconfiguration of Zookeeper works for > > Zookeeper – that is adding/removing nodes automatically without having > > to reconfigure each zookeeper node manually. Once Zookeeper is out of > > Alpha then Solr will be updated to take advantage of the Dynamic > > Reconfiguration capability of Zookeeper and auto-discover any changes. > > Is that correct? > > I am not sure whether my understanding is correct, but if it is, then I > don't think a zookeeper 3.4.x client (like the one in Solr) will notice > that the server list (with servers running 3.5.x) has changed. > Depending on exactly how the membership changed, the SolrCloud instance > might not be able to maintain a viable ZK quorum. If it loses quorum, > SolrCloud goes read-only. > > After ZK 3.5 goes through the beta phase and reaches stable, then Solr > will get the upgrade, and we will make sure that the dynamic > reconfiguration works. It's a feature that we definitely want, though > we may wait for the second or third stable release before we upgrade to > be absolutely certain that it's solid. > > There are a couple of questions I do not know the answer to: 1) Whether > any code changes will be required in Solr to take advantage of dynamic > reconfiguration after the dependency upgrade. 2) Whether a Solr > instance with the 3.5 client could be told about only one ZK server, > then discover the whole cluster and connect to all the servers. Can a > more knowledgeable member of this community answer these questions for me? > > Thanks, > Shawn > >
