Hi @ctdemato ,
As per my understanding the Problem recap:
* Virtual desktops (VDIs) get created and destroyed frequently.
* Each new instance might have different IP/MAC but same name.
* vCenter discovery typically creates new VMs each time because by default it uses identifiers like instance UUID, BIOS serial, or MAC, not just name.
* This leads to hundreds of obsolete CIs in the CMDB.
Solution & Best Practices:
1. Use a custom Identification Rule:
* Go to CI Class Manager → Identification Rule.
* Create or adjust the rule for the class cmdb_ci_vm_instance (or the class used for virtual desktops).
* In Advanced mode, add Name (name field) as an identifier (primary or secondary).
* This forces IRE to match incoming records by name instead of unique hardware attributes.
Note: This only works if your desktop names are truly unique and stable.
If there’s a chance the same name might appear on two different active VMs, you risk collisions.
2. Use Discovery Conditions or Filters:
* Configure discovery schedule or patterns to exclude ephemeral VMs (by name pattern, folder, or tag).
* For example, exclude VMs whose name starts with TEMP- or are in a known folder.
3. Use Lifecycle Management:
* Use Data Manager or Staleness Policies to automatically set Install Status to Retired or Absent for VMs not seen for X days.
* Helps auto-clean old/unused VDI CIs.
4. For vCenter Discovery specifically:
* Confirm vCenter discovery does use IRE.
* By default, it sends payloads to IRE unless there’s a customization that bypasses it.
* Validate payload via Discovery Log → look for Payload sent to IRE.
If not, fix it:
* Check discovery patterns, make sure they use standard Identification Sections.* Ensure cmdb_ci_vm_instance has an identification rule and is active.
5. Consider tagging ephemeral VMs:
* In vCenter, tag such VMs (e.g., ephemeral=true) and filter them out.
* In discovery, use that tag to decide not to create/update them in CMDB.
Alternative solutions:
* Instead of adding them into CMDB, track ephemeral desktops separately in a non-CMDB table.
* Use Dynamic CI Groups to track them live if needed, without persisting all CIs.
Suggestion :
* Adjust Identification Rule to include name as key identifier.
* Validate vCenter discovery really calls IRE.
* Use Data Manager to auto-retire old CIs.
* Filter ephemeral VMs at discovery or tagging level.
Thank You
AJ - TechTrek with AJ - ITOM Trainer
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ServiceNow Community MVP 2025
