Is It Appropriate to Create New Devices When Virtual Machine Instance Already Exists in CMDB?

[shubhamkhai]

Hi Community,

I have a question regarding the management of VMware Virtual Machine Instance records in ServiceNow. Currently, I have records in the cmdb_ci_vmware_instance table, but I now need to import data from IH-ETL. The incoming data contains records that are similar to the existing entries in cmdb_ci_vmware_instance, but with additional attributes specific to classes like cmdb_ci_computer/cmdb_ci_windows_server/cmdb_ci_linux_server , which I’ve classified based on OS values.

Upon reviewing the data, I noticed that the information in both classes (e.g., cmdb_ci_vmware_instance and OS-related classes like cmdb_ci_win_server) appears to be very similar for the common attributes, with the primary differences being class-specific attributes.

My Question:
Is it appropriate to create new records in these classes even though a virtual machine instance for the same device already exists in the CMDB?
Should these new records be considered duplicates, or is it acceptable to represent the same device in different classes, each with its own set of specific attributes?
I would appreciate any insights or best practices on whether this approach is suitable.

Thanks!

[Kieran Anson · Accepted solution]

Hi,

It is absolutely fine to create a "virtual" record in one of the virtual instance extension classes, as-well as a CI in a child class of cmdb_ci_computer. ServiceNow Discovery does it, as well as Service Graph Connectors. As you've identified, they hold different attribute level information. 

Make sure to create a Virtualized by::Virtualizes relationship between the two classes.

[shubhamkhai]

Thanks for your response 😊!

Yes, in my current setup, I can see the following relationships exist:

1. Virtualized by::Virtualizes → (Linux Server - ESXi Host)
2. Instantiates::Instantiated by → (Linux Server - Virtual Machine Instance
3. Registered on::Has registered → (Virtual Machine Instance - ESXi Host)