Setting up multiple servers to monitor the infrastructure using Nagios is not trivial. However, is not very hard either. It only requires a slightly different approach as compared to setting up a single machine. That said, there are issues with the configuration of hosts and services themselves. It is also necessary to set up all slave and master servers correctly, and in a slightly different way.

Distributed monitoring requires having a more mature change control and versioning process for Nagios configurations. This is necessary because both the central Nagios server and its branches need to have a partial or complete configuration available, and these need to be in sync across all machines.

Usually, it is recommended that you make the slave servers query both the service and the host status. It is also recommended that you disable service checks on the master Nagios server, but keep the host checks enabled. The reason for this is that host checks are not...