Discovery
Discovery is ServiceNow's agentless process that scans networks through a MID Server, identifies devices and applications, and creates or updates the matching CIs in the CMDB.
Also searched as: ServiceNow Discovery, agentless discovery, horizontal discovery.
In practice
A Discovery Schedule triggers a port scan, classifiers decide what the device is, and probes and sensors collect and parse the attributes. Everything it writes goes through the Identification and Reconciliation Engine, so the same host found twice updates one CI instead of creating two.
Example
A schedule scans 10.20.0.0/24 nightly: SSH responds, the Linux classifier matches, probes return CPU, memory and running processes, and cmdb_ci_linux_server is updated.
What interviewers check
The classic question is 'device found but not classified' — the answer is credentials, probe output or a missing classifier, not the port scan.
Practise this topic
Related CMDB terms
- Configuration Item (CI)A Configuration Item is any component you need to manage in order to deliver an IT service — a server, an application, a laptop, a service — stored on cmdb_ci or one of its extended class tables.
- CMDBThe CMDB (Configuration Management Database) is the set of related tables that record the CIs in your environment and the relationships between them, acting as the single source of truth for service context.
- CSDMCSDM (Common Service Data Model) is ServiceNow's prescriptive blueprint for how to model services, applications and infrastructure so every product on the platform reads the same data the same way.