Monitoring still works without agent setup


I am new to icinga2. During the last week, I was reading through the documentation to try to understand icinga2. I also did some setup but there are still something that confuses me and I hope very much that you can help me to clarify.

  1. Is it a must to have at least one master and zone setup? Why do I need zone when I can just put my host/services config under /etc/icinga2/conf.d?

  2. On the Linux client that i want to monitor, there is no agent setup, no ssh enabled. However the checks like disk/load for this this client still returns correct state. How was the state returned to the icinga2 server, i mean via which channel? I even did the tcpdump during the service/host check and saw no traffic between them.

I know that it sounds very basic stuff. But I hope one can help me to clarify. I am really confused.

Thanks and Best regards!

Hi & welcome to the icinga community,

Among other things zones and endpoints are required to determine where checks are executed. You need to have a master zone at least. With that you would be able to run local checks on the master node and remote checks e.g. http or ssh. But if you need to run local checks e.g. disk on a satellite or an agent (which should be the normal case), you need additional zones.

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Hi Roland,

Thank you very much for your answer. it shed some light.
I just realized that for remote checks on agents (actually not working) and icingaweb displays the result of the check on master instead of giving me a hint about that.
back to the zone topic, in my case, I need to set up icinga server to do the remote checks using ssh. So as I understand, setting up zone in this case is not required, is it correct? I just need to have the correct config for Service using check_by_ssh and put all Hosts/Services config under /etc/icinga2/conf.d?

Thanks in advance!

Just one master zone is enough in this case, yes. And without additional zones it does not matter where to put the config files. However, I’d suggest to follow the recommendations anyway (that might help for support questions and if your requirements changes in future and you are forced to have additional zones).