After Update: "[agent] Error establishing TLS connection" on all hosts

Troubleshooting
1

CMK version: 2.1.0p28.cee
OS version: RHEL 8.0

Error message:
We are currently running 2.1.0p28.cee and all hosts are registered using TLS. No issues at all. When I updated to 2.1.0p36.cee (as an intermediate step to getting to 2.2), all of our hosts failed with the error “[agent] Error establishing TLS connection”. This is all hosts, Windows and Linux.

My update process:

  1. omd stop
  2. omd update
  3. omd start

Any help would be appreciated.

2

Have you taken a look at the logs already?
If something went sideways, you should see something in the logs under $OMD_ROOT/var/log/.

3

I looked at the logs, but didn’t see anything noticeably wrong. The update completed successfully and I am able to access the web UI. All devices that are using SNMP (network switches, etc.) are working perfectly. The issue is only with servers that are using the checkmk agents.

This is the first upgrade after we setup TLS so I assume it has something to do with it. Am I supposed to re-register agents after an upgrade now?

4

Sorry for the late reply.

In general, no re-registration is necessary, even on major upgrades.

The question here is: What is the exact error message?