[ZOOKEEPER-4567] Sometimes ruok closes the connection without returning anything

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 3.7.1
• Component/s: server

Environment

zookeeper:3.7.1 Docker image

• Assignee: Unassigned
• Reporter: Benoit Sigoure
• Created: 29/Jun/22 19:50
• Updated: 22/Jul/22 13:35

Description

$ while true; do echo -n .; res=`echo ruok | nc -v 127.0.0.1 2181 2>&1`; case $res in (*imok*) :;; (*) echo res=$res; break;; esac; done
......................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................res=Connection to 127.0.0.1 2181 port [tcp/*] succeeded! 

Server logs don't contain smoking guns:

[...]
2022-06-29 19:40:07,354 [myid:1] - INFO  [NIOWorkerThread-4:NIOServerCnxn@514] - Processing ruok command from /127.0.0.1:60440
2022-06-29 19:40:07,359 [myid:1] - INFO  [NIOWorkerThread-2:NIOServerCnxn@514] - Processing ruok command from /127.0.0.1:60442
2022-06-29 19:40:07,364 [myid:1] - INFO  [NIOWorkerThread-3:NIOServerCnxn@514] - Processing ruok command from /127.0.0.1:60444
2022-06-29 19:40:07,369 [myid:1] - INFO  [NIOWorkerThread-4:NIOServerCnxn@514] - Processing ruok command from /127.0.0.1:60446
2022-06-29 19:40:10,216 [myid:1] - INFO  [NIOWorkerThread-2:NIOServerCnxn@514] - Processing ruok command from /127.0.0.1:60490
2022-06-29 19:40:10,293 [myid:1] - INFO  [NIOWorkerThread-4:NIOServerCnxn@514] - Processing ruok command from /127.0.0.1:60516 

I can reproduce this consistently very easily.