Nagios Support Forum

How can I setup the parent/child relationship in a VMware cluster when the VM's get moved around the cluster?

We also have Nutanix clusters but those have an IP address so making a host that uses that IP and assigning that host as the parent was easy enough. The parent/child relationship is important for silencing extraneous alerts and NagVis maps (which work well for our Nutanix parent/child setup). I'm stumped on how to do the same thing with our VMware clusters.

My 2 cents here.

In my setup, I use the system's default gateway as a parent IP.

Basically, If Nagios cannot get to the Default gateway on a subnet, then it cannot see any systems there either. So instead of 255 host down messages, I just get the one DG is down message.

Since my VMs also move between ESX hosts, I cannot use the host in an intelligent parent child relationship. It would have to detect changes and make updates on a continual basis.

YMMV

Steve B

Thanks for your input.

Model the parent as the vCenter cluster object instead of the ESXi host — that way VM moves won’t break your hierarchy

athenasmith wrote: ↑Sun Sep 14, 2025 9:48 pm Model the parent as the vCenter cluster object instead of the ESXi host — that way VM moves won’t break your hierarchy

How would you do that when the VMware cluster has no IP address?

So, what strategies can be implemented to ensure that the parent/child relationship in VMware clusters remains consistent

Sophiana wrote: ↑Fri Oct 10, 2025 5:24 am So, what strategies can be implemented to ensure that the parent/child relationship in VMware clusters remains consistent

I followed this setup and used the gateway IP address of the network the cluster is on as a 'host' in Nagios. The hosts and vm's now use that as a parent in our instance.

StevenBeauchemin wrote: ↑Wed Sep 10, 2025 10:06 am My 2 cents here.

In my setup, I use the system's default gateway as a parent IP.

Basically, If Nagios cannot get to the Default gateway on a subnet, then it cannot see any systems there either. So instead of 255 host down messages, I just get the one DG is down message.

Since my VMs also move between ESX hosts, I cannot use the host in an intelligent parent child relationship. It would have to detect changes and make updates on a continual basis.

YMMV

Steve B

In a VMware cluster, since VMs can move between hosts due to vMotion, it’s best to define the parent/child relationship at the vCenter or cluster level instead of individual ESXi hosts. Use the vCenter server or a virtual cluster object as the parent, and link the VMs to it dynamically through your monitoring tool’s API or VMware’s vSphere plugin integration. This ensures relationships persist even when VMs migrate between hosts, maintaining proper alert silencing and NagVis mapping without manual reconfiguration.Nulls Brawl

rocky07 wrote: ↑Fri Oct 17, 2025 11:07 pm a virtual cluster object as the parent

How exactly are you configuring your Nagios to monitor your virtual cluster?

One option to consider would be to use BPI.

First, create a BPI group that meaningfully reflects the status of the VMware cluster as a whole.

Next, run the BPI wizard to create a monitored object that represents the BPI group's status.

Finally, make the BPI group the parent of the VMs, that way even as VMs move around, alert states and notifications will be logically based on the cluster status, not an individual cluster server.

As a bonus benefit, root cause analysis of the cluster will be easier, since you can just crack open the BPI group to see exactly what hosts/services are causing issues.