Zookeeper - Where do I find the "real" version of a running instance of Zookeeper?

Question

I recently installed a new ZK node w/ Exhibitor, it started fine. When I do a telnet localhost 2181 and then run a stats to see the version, even though I installed 3.4.11, I keep seeing 3.4.5 build in the output. I tried to find where does ZooKeeper read the version number but it's just a .jar and some lib files. Do you know where can I get the "real" version I'm supposed to be running? Thanks!

This is what I see when doing telnet:

myserver:/tmp/zookeeper # telnet localhost 2181
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
stats
Zookeeper version: 3.4.5-1392090, built on 09/30/2012 17:52 GMT
Clients:
 /127.0.0.1:53133[0](queued=0,recved=1,sent=0)

Latency min/avg/max: 0/0/0
Received: 41
Sent: 40
Connections: 1
Outstanding: 0
Zxid: 0x0
Mode: standalone
Node count: 4
Connection closed by foreign host.

Running process (ps aux | grep zookeeper) shows:

myuser    19002  0.9  1.2 2618596 49596 ?       Sl   14:02   0:00 /usr/pkgs/java/1.8.0.92/bin/java -Dzookeeper.log.dir=/var/run/zookeeper/log -Dzookeeper.root.logger=WARN,ROLLINGFILE -cp /opt/zookeeper-server/default/bin/../build/classes:/opt/zookeeper-server/default/bin/../build/lib/*.jar:/opt/zookeeper-server/default/bin/../lib/slf4j-log4j12-1.6.1.jar:/opt/zookeeper-server/default/bin/../lib/slf4j-api-1.6.1.jar:/opt/zookeeper-server/default/bin/../lib/netty-3.10.5.Final.jar:/opt/zookeeper-server/default/bin/../lib/log4j-1.2.16.jar:/opt/zookeeper-server/default/bin/../lib/jline-0.9.94.jar:/opt/zookeeper-server/default/bin/../lib/exhibitor-1.6.0.jar:/opt/zookeeper-server/default/bin/../lib/audience-annotations-0.5.0.jar:/opt/zookeeper-server/default/bin/../zookeeper-3.4.11.jar:/opt/zookeeper-server/default/bin/../src/java/lib/*.jar:/var/run/zookeeper/conf: -server -Xmx1g -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.local.only=false org.apache.zookeeper.server.quorum.QuorumPeerMain /var/run/zookeeper/conf/zoo.cfg

Answer 1

ZooKeeper supports four letter commands, assuming you're running ZooKeeper on localhost:

$ echo "status" | nc  localhost 2181 | head -n 1
Zookeeper version: 3.4.9-3--1, built on Fri, 24 May 2019 08:57:53 +0100

using some bash magic, you can filter out the main version:

$ echo "status" | nc  localhost 2181 | head -n 1 | awk '{ print $3}' | cut -d "-" -f 1

Answer 2

cat zookeeper-server.log | grep zookeeper.version

.... INFO Server environment:zookeeper.version=3.5.7-f0fdd52973d373ffd9c86b81d99842dc2c7f660e, built on 02/10/2020 11:30 GMT (org.apache.zookeeper.server.ZooKeeperServer) .....