Druid Zookeeper Connection Error with Kafka Datasource

Hello,

I am using druid 0.21.0 and i am getting following error. My zookeeper working. I can send data from kafka but druid always getting error and can't read data from kafka. Thanks for help.

2021-05-06T11:20:10,613 WARN [main-SendThread(localhost:2181)] org.apache.zookeeper.ClientCnxn - Session 0x0 for server localhost/:2181, unexpected error, closing socket connection and attempting reconnect
java.lang.IllegalArgumentException: Unable to canonicalize address localhost/:2181 because it's not resolvable
at org.apache.zookeeper.SaslServerPrincipal.getServerPrincipal(SaslServerPrincipal.java:65) ~[zookeeper-3.4.14.jar:3.4.14-4c25d480e66aadd371de8bd2fd8da255ac140bcf]
at org.apache.zookeeper.SaslServerPrincipal.getServerPrincipal(SaslServerPrincipal.java:41) ~[zookeeper-3.4.14.jar:3.4.14-4c25d480e66aadd371de8bd2fd8da255ac140bcf]
at org.apache.zookeeper.ClientCnxn$SendThread.startConnect(ClientCnxn.java:1001) ~[zookeeper-3.4.14.jar:3.4.14-4c25d480e66aadd371de8bd2fd8da255ac140bcf]
at org.apache.zookeeper.ClientCnxn$SendThread.run(ClientCnxn.java:1060) [zookeeper-3.4.14.jar:3.4.14-4c25d480e66aadd371de8bd2fd8da255ac140bcf]

Start with the Druid 0.21.0 Kafka datasource setup and the reported ZooKeeper stack trace. Check how the connection to localhost:2181 is configured and determine whether the failure is reproducible in Druid or the ZooKeeper client. Done requires a confirmed root cause and a clear fix or configuration guidance.

Written by the indexing model from the issue text.