Nagios check whether at least one out of two services is OK

I have two following passive services: ServiceA, ServiceB on one machine.

I would like to have a sittuation when the OK state is satisfied by following conditions:

• ServiceA is OK or ServiceB is OK
• ServiceA is OK and SericeB is OK

I would like to have alarm when:

• ServiceA is down and Service B is down

What configuration option should I use to implement that? Servicedependency looks good but I had no luck with that one.

check_cluster is the "old school" way to do it, as mentioned already. But it's kludgy at best.

check_multi is a much better option for this; it is designed for exactly what you want.

This is known as monitoring a "cluster" of services. You can use the check_cluster script.

The documented method uses a wrapper script like this instead of calling it directly:

define command{

command_name    check_service_cluster

command_line    /usr/local/nagios/libexec/check_cluster --service -l $ARG1$ -w $ARG2$ -c $ARG3$ -d $ARG4$ 

}

and then defining your own specific service:

define service{

...

check_command   check_service_cluster!"DNS Cluster"!1!2!$SERVICESTATEID:host1:dnsservicename,$SERVICESTATEID:host2:dnsservicename,$SERVICESTATEID:host3:dnsservicename

...

}

In this example 1/3 services not OK is a warning, 2/3 services not OK is a critical.

Nagios Docs

More explanation in Groundworks knowledge base