Empty payload from controller

Troubleshooting
1

2.2.0p21
linux

Hello guys.

All of a sudden a host is reporting ‘Empty payload from controller’. No modification have been done on both the host and monitoring server.

Since the host is relatively new I have deleted it and added it again, however without success.

Tried re-installing the check-mk-agent, deleting all the files, removed the TLC registration, however without success.

The port is open and a connection is established, but the:

cmk --debug -vnn HOST

[agent] Empty payload from controller at IP:6556

On the host side the check_mk_agent returns all the data successfully, however running:

cmk-agent-ctl -vv dump


Caused by:
    Connection reset by peer (os error 104)

netstat -plan | grep 6556
tcp6 0 0 :::6556 :::* LISTEN 454235/cmk-agent-ct
tcp6 0 0 XXXXX:6556 XXXXXXX:50356 TIME_WAIT -

I am just out of ideas. Any hints will be greatly appreciated.

Thank you!

Marcus

2

The issue was related to a Kernel bug, killing check_mk agent. The kernel version is a CloudLinux one:

4.18.0-477

oom-kill:constraint=CONSTRAINT_MEMCG,nodemask=(null),cpuset=/,mems_allowed=0,oom_memcg=/system.slice/system-check\x2dmk\x2dagent.slice,task_memcg=/system.slice/system-check\x2dmk\x2dagent.slice,task=(mk_agent),pid=3031891,uid=0
May 8 13:11:30 local kernel: Memory cgroup out of memory: Killed process 3031891 ((mk_agent)) total-vm:261388kB, anon-rss:6096kB, file-rss:2092kB, shmem-rss:0kB, UID:0 pgtables:236kB oom_score_adj:0

Updating the kernel to 4.18.0-513 solved the issue.

All the best,

Marcus