Agent error: Communication failed: timed out

Troubleshooting
1

Hello, i am unable to scan services from a newly installed Agent. Both CheckMK Server and monitored host are in the same Network, CheckMK Rule in Windows Firewall exists and is enabled. Both machines can reach each other via ping.

CMK version: Checkmk Managed Services Edition 2.2.0p21
OS version: Windows Server 2016

Error message: [agent]: Communication failed: timed out

Output of “cmk --debug -vvn hostname”: (If it is a problem with checks or plugins)

OMD[medianet_mon01]:~$ cmk --debug -vvn HOSTNAME
Checkmk version 2.2.0p21
+ FETCHING DATA
  Source: SourceInfo(hostname='HOSTNAME', ipaddress='IPADDR', ident='agent', fetcher_type=<FetcherType.TCP: 8>, source_type=<SourceType.HOST: 1>)
[cpu_tracking] Start [7faf8ecd6450]
Read from cache: AgentFileCache(HOSTNAME, path_template=/omd/sites/medianet_mon01/tmp/check_mk/cache/{hostname}, max_age=MaxAge(checking=0, discovery=90.0, inventory=90.0), simulation=False, use_only_cache=False, file_cache_mode=6)
Not using cache (does not exist)
[TCPFetcher] Execute data source
Connecting via TCP to IPADDR:6556 (5.0s timeout)
Closing TCP connection to IPADDR:6556
[cpu_tracking] Stop [7faf8ecd6450 - Snapshot(process=posix.times_result(user=0.0, system=0.0, children_user=0.0, children_system=0.0, elapsed=5.0))]
+ PARSE FETCHER RESULTS
  HostKey(hostname='HOSTNAME', source_type=<SourceType.HOST: 1>)  -> Not adding sections: TimeoutError('timed out')
Received no piggyback data
[cpu_tracking] Start [7faf8e1f3b10]
value store: synchronizing
Trying to acquire lock on /omd/sites/medianet_mon01/tmp/check_mk/counters/HOSTNAME
Got lock on /omd/sites/medianet_mon01/tmp/check_mk/counters/HOSTNAME
value store: loading from disk
Releasing lock on /omd/sites/medianet_mon01/tmp/check_mk/counters/HOSTNAME
Released lock on /omd/sites/medianet_mon01/tmp/check_mk/counters/HOSTNAME
[cpu_tracking] Stop [7faf8e1f3b10 - Snapshot(process=posix.times_result(user=0.0, system=0.0, children_user=0.0, children_system=0.0, elapsed=0.0))]
[agent] TimeoutError('timed out')(!!), execution time 5.0 sec | execution_time=5.000 user_time=0.000 system_time=0.000 children_user_time=0.000 children_system_time=0.000 cmk_time_agent=5.000
2

Did you try with telnet to port 6556 from CheckMk server to the host?

3

Also does not work, timeout. Windows Firewall has been disabled. According to netstat -aon the machine is listening on port 6556.

4

Try deleting TLS registration to ensure it hasn’t a previously registration to other checkmk server.

“C:\Program Files (x86)\checkmk\service\cmk-agent-ctl.exe” delete-all --enable-insecure-connections

Also, you can make a traceroute from checkmk to host to verify the traffic.

if you make a telnet to port 6556 directly on host, it respond?

1 Like
5

Also check your central firewalls and IPS.