Clustered service with HTTP checks

CMK version: 2.0.0p15
OS version: Ubuntu 20.04 LTS

Hi,

I have been trying to set up clustered service monitoring using the in-built check.

We have two servers running in active/backup configuration and producing HTTP page which we check via regular HTTP check.

Server 1: http://server1.local:4000/some_path
Server 2: http://server2.local:4000/some_path

Now because Server2 is cold backup active check produces Critical, so I wanted to create a Cluster in Checkmk following the official docs explanation (Monitoring cluster services)

The service name begins with HTTP Some Service Name, and after setting the cluster I can’t get the services to be shown under the Cluster Host.

They disappear from cluster nodes though.

I tested with Filesystem service and that works OK.

What am I doing wrong?

Thanks,
M

Hi,

I have to come back to this problem once again.

I have created an SMB active check which checks a certain network share on storage with two controller devices.

These services are seen fine when I go into hosts and on those two hosts.

But when I create a cluster host and add those two hosts, create clustered services according to the documentation, and do bulk discovery, those services disappear from the original hosts but do not show up on the clustered host.

Are there some problems with clustering active checks? Since I had this issue also with the HTTP checks on different hosts and couldn’t find a solution.

If so is there a workaround to monitor clustered active checks?

Thanks

There is no real problem with active checks on clusters.
But you need to configure these active checks different from the normal CheckMK passive checks.

If your cluster provides a floating IP/name create a normal host object with settings “no agent” and “no snmp”. You should now have a ping only host. Now assign an active check HTTP/SMB to this host object and not to your cluster nodes.

The “normal” cluster functionality works only if the cluster is an active/passive and if the checks are normal CheckMK checks.

Hi @andreas-doehler

Thanks for your reply. Didn’t know that the active checks in a cluster are configured differently.
I did just as you suggested and is working.

Problem solved.

Thanks,
M

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