What should be the order of running discovery on devices - Network Gear, Vmware vCenter, Servers ?

[Shubham_Jain]

@Sumit Das1  Is there any specific reason you want to run in order? 

At end, all data will come in CMDB and will relate as it is. 

If a tall you need this in Service Mapping, so better idea is first complete the 85% device Discovery and then only go with Service Mapping so that you have all the data in CMDB.

[AJ-TechTrek]

Hi @Sumit Das1 ,

step-by-step solution on how to run discovery in ServiceNow — and why the order matters.

1. Why the order matters
Discovery in ServiceNow CMDB builds a dependency tree:
* Network Gear → gives you routers/switches/subnets/IP ranges
* vCenter → gives you virtualization layer and VMs
* Servers → are often discovered later, and mapped properly only if you already have their hosting context (e.g., which ESXi, cluster, etc.)
Correct order ensures relationships like:
* Hosted on
* Runs on
* Depends on
… are built correctly.

1. Network Gear
* Purpose: Discover routers, switches, subnets, and IP connectivity.
* Why first:
* Populates Layer 2 and Layer 3 relationships.
* Helps IP Services to identify which devices are connected.
* Ensures that vCenter and server IPs are reachable and properly mapped.
Run:
* Horizontal Discovery → Network Gear (using SNMP credentials).

2 vCenter (VMware)
* Purpose: Discover vCenters, clusters, ESXi hosts, data stores, resource pools, and VMs.
* Why second:
* Creates the virtualization hierarchy.
* Populates relationships: ESXi → VM → Datastore.
Run:
* VMware pattern discovery (with vCenter credentials).
* This requires vCenter endpoint to be in CMDB or discoverable from network.

3 Servers
* Purpose: Discover OS and installed software on physical and virtual servers.
* Why last:
* Server discovery can now tie discovered virtual machines to the existing VM CIs created from vCenter.
* Populates Runs on::Runs and Hosted on::Hosts relationships correctly.
Run:
* Windows or Unix discovery patterns (with domain/local credentials).

Final checklist:
* Make sure your MID Server is placed properly (network access to all targets).
* Configure and test credentials before discovery.
* Use Discovery Schedules to automate the runs in this order.
* Monitor Discovery Logs & Discovery Status for errors.
* Use CMDB Health Dashboard to validate relationships and completeness.

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Thank You
AJ - TechTrek with AJ
LinkedIn:- https://www.linkedin.com/in/ajay-kumar-66a91385/
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ServiceNow Community MVP 2025