ServiceNow CMDB: Tables, CIs and Relationships

ServiceNow CMDB

The single source of truth for your IT estate.

Quick answer

The ServiceNow CMDB is the table hierarchy under cmdb_ci that records every configuration item in your estate, servers, applications, databases and network devices, and the relationships between them. Discovery and Service Mapping populate it. Change impact analysis, event correlation and most of ITOM read from it, so its accuracy decides whether those work.

Key takeaways

CIs and the class hierarchy
Try it: query the CMDB
Relationships are the whole point
Keeping it trustworthy
How it's populated

The Configuration Management Database (CMDB) is the single source of truth for your IT estate, every server, database, application and, critically, the relationships between them. It underpins change impact analysis, event correlation and most of ITOM. A trustworthy CMDB is the hardest and most valuable thing to get right.

CMDB structure: configuration items, classes and relationships under a business service.

CIs and the class hierarchy

Everything in the CMDB is a Configuration Item (CI), a record extending the base class cmdb_ci. Specific classes extend it in the table hierarchy, inheriting common fields and adding their own:

cmdb_ci
 +- cmdb_ci_hardware --> cmdb_ci_computer --> cmdb_ci_server --> cmdb_ci_linux_server
 +- cmdb_ci_appl (application) --> cmdb_ci_web_server
 +- cmdb_ci_database --> cmdb_ci_db_mysql_instance
 +- cmdb_ci_network_adapter, cmdb_ci_ip_router, ...

Try it: query the CMDB

Everything in the CMDB is reachable from a script. Run this to list active configuration items with GlideRecord, then edit it, change the table to incident or add your own gs.info() line:

Try it YourselfJavaScript

▸ Press Run to execute.

Runs in a sandbox in your browser. Mock gs and GlideRecord and sample data are provided.

Authoritative sources

ServiceNow CMDB documentation - CMDB, CI classes and IRE reference
ServiceNow CSDM framework - Common Service Data Model guidance

FAQ

What is CMDB in ServiceNow?

The CMDB (Configuration Management Database) is the single source of truth for your IT estate. It stores configuration items (CIs), servers, databases, applications, and the relationships between them, which power change impact analysis, event correlation and most of ITOM.