Shawn, Thanks for this. I will try dig further into the ZooKeeper documentation.
From a matter of perspective, however, I think what I am not clear on is having more than one ZK “server”, and when and why I would need more than one? Perhaps it is just terminology, but if I have three (3x) Solr instances (cores) running on three (3x) separate physical servers (different hardware), and I want to replicate shards between those three, do I have all three (3x) Solr instances (cores) taking to the same single (1x) ZooKeeper “server"? Or if I have three (3x) Solr instances (cores) replicating shards between them, do I also need three (3x) ZooKeeper “servers”, e.g., server.1, server.2, server.3, each “server” assigned to one specific Solr instance (core)? So while I understand this the might not be place to talk about configuring ZooKeeper per se, if its not too much trouble, can you please clarify if there is a many-to-one relationship between Solr and ZooKeeper (many Solr cores talking to one ZooKeeper “server”, which communicates between them), or there a one-to-one relationship (each Solr instance (core) talks to one ZooKeeper “server”). I hope that is clear and an easy question to answer? Once I understand that, I think I can figure this out with what I have found and been given. Thanks, Dave. > On Oct 20, 2023, at 4:47 PM, Shawn Heisey <elyog...@elyograg.org.INVALID> > wrote: > > On 10/20/23 13:34, David Filip wrote: >> Understand about redundancy and needing an odd number of nodes (I’ve used >> quorum in other (non-Solr) type of clusters, so I get it). >> So what I’ve done now is installed ZooKeeper on a separate (physical) node >> (so no longer using ZooKeeper bundled with Solr, since that was causing come >> confusion). >> So I’m trying to follow this document regarding how to set up the “Ensemble” >> for Solr: >> Setting Up an External ZooKeeper Ensemble | Apache Solr Reference Guide 6.6 >> <https://solr.apache.org/guide/6_6/setting-up-an-external-zookeeper-ensemble.html> >> solr.apache.org >> <https://solr.apache.org/guide/6_6/setting-up-an-external-zookeeper-ensemble.html> >> favicon.ico >> <https://solr.apache.org/guide/6_6/setting-up-an-external-zookeeper-ensemble.html> >> <https://solr.apache.org/guide/6_6/setting-up-an-external-zookeeper-ensemble.html> >> This includes the following “example” in zoo.cfg: >> |dataDir=/var/lib/zookeeperdata/1 clientPort=2181 initLimit=5 syncLimit=2 >> server.1=localhost:2888:3888 server.2=localhost:2889:3889 >> server.3=localhost:2890:3890| >> So assuming that I have three (3x) physical nodes — each running Solr 9.2 — >> and assuming that they are named: >> solr1.mydomain.com <http://solr1.mydomain.com> >> solr2.mydomain.com <http://solr2.mydomain.com> >> solr3.mydomain.com <http://solr.mydomain.com> > > This is getting into how to configure ZK, which is a completely separate > Apache project from Solr. My info here is from memory. > > Those names will only work if each ZK instance is on the same machine as a > Solr instance. ZK is completely separate from Solr, you do not tell it > anything about Solr. You also need the port numbers. If ZK will be on the > same machines as Solr, I would use something like this, and the ZK config > will be identical on all the ZK servers: > > dataDir=/path/to/some/data/directory > clientPort=2181 > initLimit=5 > syncLimit=2 > server.1=solr1.mydomain.com:2888:3888 > server.2=solr1.mydomain.com:2888:3888 > server.3=solr1.mydomain.com:2888:3888 > > You must ensure that the ZK servers can talk to each other on tcp ports 2888 > and 3888, and that each Solr server can reach all the ZK servers on port > 2181. For most purposes, you do not want to use localhost. > > Each server will have a file with its id number. I think it is named "myid" > in the data directory, but you should check ZK documentation to make sure. > > The -z option on the solr script would be something like this: > > solr1.mydomain.com:2181,solr2.mydomain.com:2181,solr3.mydomain.com/solr > > For redundancy purposes, every Solr server will need to talk to ALL of the ZK > servers, not just one. > > Adding a chroot (which is /solr in my example) is encouraged just in case you > might want to use your ZK install to coordinate software other than Solr or > for multiple SolrCloud clusters. The Solr reference guide has info about how > to create the chroot with a 'bin/solr zk' command. > > Thanks, > Shawn >
