ServiceNow CMDB

You are a ServiceNow CMDB administrator. The user wants to configure the Configuration Management Database (CMDB) by setting up CI (Configuration Item) classes, defining relationships between them, and enabling discovery processes.

What to check first

• Verify you have the CMDB and Discovery and Service Mapping plugins enabled in your ServiceNow instance via Plugins module
• Check your user role includes cmdb_admin or admin to access CMDB configuration tables
• Review existing CI classes in CMDB > Administration > CI Classes to understand current schema

Steps

1. Navigate to CMDB > Administration > CI Classes and click New to create a custom CI class that extends from a base class like cmdb_ci_server or cmdb_ci_app_server
2. Define the class properties: set Name, Label, Parent Class, and Table name (should follow naming convention like cmdb_ci_custom_app)
3. Add custom attributes to your CI class by going to the Attributes tab and inserting new fields with appropriate field types (text, reference, choice, etc.)
4. Create relationships between CI classes via CMDB > Administration > Relationships by defining From Class, To Class, Relationship Type (e.g., "depends on", "runs on"), and cardinality
5. Configure Discovery patterns in Discovery and Service Mapping > Discovery > Patterns to auto-populate CIs—select probe type (SNMP, SSH, WMI), set credentials, and define CI matching rules
6. Enable Reconciliation rules in CMDB > Administration > Reconciliation Rules to merge duplicate CI records based on matching attributes
7. Test CI creation by manually adding a record to your custom CI class table, then verify relationships appear in CMDB > Assets > [Your CI Class]
8. Schedule discovery jobs in Discovery and Service Mapping > Discovery > Discovery Schedule and set triggers (on-demand or recurring)

Code

// Script to programmatically create a CI class, add attributes, and establish relationships

(function() {
  // Step 1: Create a new CI class
  var ciClass = new GlideRecord('cmdb_ci_class');
  ciClass.setValue('name', 'cmdb_ci_custom_database');
  ciClass.setValue('label', 'Custom Database');
  ciClass.setValue('parent', 'cmdb_ci_database'); // Extend from base database class
  ciClass.setValue('table_name', 'cmdb_ci_custom_database');
  ciClass.setValue('description', 'Custom CMDB CI class for enterprise databases');
  var classId = ciClass.insert();
  gs.info('Created CI class: ' + classId);

  // Step 2: Add custom attributes to the CI class
  var attribute1 = new GlideRecord('cmdb_ci_class_attribute');
  attribute1.setValue('class_id', classId);
  attribute1

Note: this example was truncated in the source. See the GitHub repo for the latest full version.

Common Pitfalls

• Treating this skill as a one-shot solution — most workflows need iteration and verification
• Skipping the verification steps — you don't know it worked until you measure
• Applying this skill without understanding the underlying problem — read the related docs first

When NOT to Use This Skill

• When a simpler manual approach would take less than 10 minutes
• On critical production systems without testing in staging first
• When you don't have permission or authorization to make these changes

How to Verify It Worked

• Run the verification steps documented above
• Compare the output against your expected baseline
• Check logs for any warnings or errors — silent failures are the worst kind

Production Considerations

• Test in staging before deploying to production
• Have a rollback plan — every change should be reversible
• Monitor the affected systems for at least 24 hours after the change