Hello @usermk,
this is perfectly normal if your agent is configured to run via systemd, which is the default when installed on a system with systemd and no xinetd installed.
You see a message every time your monitoring-server connects to the hosts checkmk-agent (the lines containing “Started Checkmk agent”) and when that request is finished (the “Succeeded” lines).
In this case the host 81.61... should be your monitoring-server.
The default configuration is that your host is checked once every minute.
As far as i know there is currently no way to suppress these messages.
You can however migrate the checkmk-service (back) to xinetd, then you won’t have these messages in your syslog from systemd but then there could be messages from xinetd for the same reasons.
Again, this is perfectly normal and just a message that your monitoring-server is contacting your host.
Hope that helps.
Cheers,
Lorenz