Discovery: How to create a relationship between a Virtual Machine and a switch?

[Cedric Creton]

Hello,

We would like to see the IP Connection::IP Connection  relationships between a virtual machine server and a switch or even a router.

It doesn't work for us, and after a discussion with our Vcenter team, I'm nearly sure it's logic and due to the vmware DVS component (virtual switch). 

In a true physical environment:

Physical server ---arp---->Physical switch     

MacAddresses of the server are collected by the arp probe/sensor and match with ARP table of the switch

In a VM environement:

VM----arp--->ESX's DVS--(other arp?)-->Physical switch

MacAddresses of the VM are collected by the arp probe/sensor but will match only with Virtual switch. When packets are transmitted to the external world by the physical switch, that's probably another mac address? So the arp table of the physical switch won't matches the macaddresses of the VMs.

Did I correctly understood?

Guess I should develop a script to

-retrieve the ESX on which the VM is running

-retrieve the Physical switch connected to the ESX

Merge info to  create an IP Connection::IP Connection  between the VM and the ESX

What's your opinion?

Best Regards

Cedric

[robertgeen]

Cedric,

Yeah this is one of the downfalls of horizontal discovery is that it gets messy when you look at virtual environments like that. I think your approach makes sense. If you look at how Service Mapping determines it, it actually uses the Layer 2 topology discovered when a switch is discovered to figure it out as well as tracert. You may want to take a look at the data that is there when you discover a switch to see if you can figure it out (as ultimately it would go back to the ESX server itself). Thanks.

[dcwilson]

Is the vCenter probe and sensor kicking off when the device hosting it is discovered?  The solution may be as simple as creating vCenter credentials for Discovery use.  

I know for certain the vCenter probe and sensor will create the relationship from VM guest to ESX host.  OOB the vCenter probe discovers all ESX hosts and when the ESX host is discovered you should get the relationship to the physical switch.

https://docs.servicenow.com/bundle/jakarta-it-operations-management/page/product/discovery/reference/r_VCenterDiscoveryAndProcessFlow.html