Parent-child relationships focuses on taking physical dependencies into account during outages, where host dependencies focus in on taking logical dependencies into account during outages. Parent-child relationships may only be defined for hosts. Parent hosts are typically routers, switches, firewalls, etc. that lie between the monitoring host and a remote host . A router, switch, etc. which is closest to the remote host is considered to be that host's parent. If this host is on the same network segment as the host doing the monitoring (without any intermediate routers, etc.) the host is considered to be on the local network and will not have a parent host .
Any host definition can optionally specify a parent directive; for example: if the parent of host A goes down, host A will be considered UNREACHABLE instead of DOWN, and while a host is in an UNREACHABLE state host and service checks and notifications will not run for that host . However, if you want you can setup notifications to be sent out for hosts with an UNREACHABLE status.
Defining parent child relationships
- Select Configuration > Nagios Monitoring > Hosts, expand the Parent Child drop-down menu, and select New.
- In the Parent Child screen, select a Parent Host from the drop-down box, select the dependent Child Hosts using the Add button, and select Save to create the parent child relationship.