CloudBolt ships with support for ServiceNow’s CMDB, but adding support for additional CMDBs is as simple as making an API call from a post-provisioning hook to register newly provisioned servers. The CloudBolt orchestration engine can also be used to unregister a server from a CMDB when it is decommissioned.
https://www.cloudbolt.io/features/integration-with-existing-technologies/
CB have a number of customers integrated with ServiceNow and are partnering with them to provide a CloudBolt iframe based catalog.
Here is an example document for creating a CI for the CMDB in ServiceNow
https://github.com/CloudBoltSoftware/cloudbolt-forge/blob/master/actions/cloudbolt_plugins/servicenow/create_servicenow_ci.py