CMDB is an essential application in ServiceNow which build the logical representation of services, assets, and relationship between the infrastructure of any organization. In this post, we will share ServiceNow CMDB Interview Questions which will give you an idea of what questions you can expect in a CMDB ServiceNow interview. There are various roles like CMDB Architect, CMDB Developer, CMDB Analyst, CMDB Manager which an organization looks for.
Table of Contents
ServiceNow CMDB Interview Questions
What is CMDB in ServiceNow?
The CMDB in ServiceNow is a database that stores all the information like computers, servers, software. CMDB is responsible for building the logical representation of services and relationships between infrastructure.
What does CMDB stand for?
Configuration Management Database (CMDB)
Share some of the core features of CMDB?
CMDB Health, CMDB CI Lifecycle Management, CMDB Identification, and Reconciliation.
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What is CI?
CI is fully known as a configuration item which is any component, infrastructure element or any item which needs to be maintained and managed in order to provide successful delivery of service. In ServiceNow, CI is a record that stores information like Name, Class, Maintenance Schedule, Manufacturer, Location, Company, Approvals, etc about the services.
How a CI can be populated in CMDB?
- Configuration items can be loaded through the manual load.
- Configuration items can be discovered via discovery integration on the customer network.
- Configuration items can be manually created by the CMDB manager.
- Can also be created through API data push from any other tool.
What is Baseline CMDB?
Baseline CMDB helps to control the changes that have been done to configuration item records in CMDB.
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What is the difference between Asset and CI?
A configuration item can be an asset but an asset may not be the configuration item. Configuration items are configurable however all assets may not be configurable. Incidents and problems are created based on the configuration item issues. Asset management is much more focused on ordering, invoicing, receiving, shipping, lease, purchase, warranty, and depreciation. The CMDB however manages the technical details on a particular item.
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Technical ServiceNow CMDB Interview Questions
Which are base tables in CMDB?
Table [cmdb] is core table.
Table [cmdb_ci] which stores basic fields values of all Cis.
Table [cmdb_rel_ci] is to define all the relationship between different types of CI’s.
Name some of the tables which extends from server table (cmdb_ci_server)?
Below are the tables which are extends from server table
- cmdb_ci_cim_server
- cmdb_ci_datapower_server
- cmdb_ci_ibm_zos_server
- cmdb_ci_isam_server
- cmdb_ci_lb
- cmdb_ci_linux_server
- cmdb_ci_mainframe
- cmdb_ci_mainframe_lpar
- cmdb_ci_netware_server
- cmdb_ci_osx_server
- cmdb_ci_server_hardware
- cmdb_ci_storage_node_element
- cmdb_ci_storage_server
- cmdb_ci_unix_server
- cmdb_ci_virtualization_server
- cmdb_ci_win_server
Name the table where CI relationship are stored?
The label of the table is CI Relationship and name is cmdb_rel_ci.
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What is dependency view map?
The dependency view map shows a graphical representation of relationships between CI’s.
Example
How to check the dependency view map of any CI?
- Open any CI which have a relationship with other CI’s
- Go to form section related Items and there you will be able to see a button that can open the dependency view. Highlighted in yellow below screenshot.
What is ServiceNow CMDB query builder?
ServiceNow CMDB query builder allows building the complex queries with non-CMDB classes and the relationships to which they are connected. It can be accessed directly from https://instancename. .service-now.com/$queryBuilder.do
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Learn more on ServiceNow CMDB query builder here
Sample queries can be accessed here
In CMDB where do we store data centers?
It is stored in cmdb_ci_datacenter.
How to test CMDB health?
To test CMDB health first the KPI’s need to be configured correctly as per the organization’s needs. Then there are data collection jobs that need to be executed either periodically or manually to calculate the three KPI’s (correctness, compliance, and completeness).
ServiceNow OOB provides the CMDB Dashboard through which you can check CMDB health.
What are identification rules?
Identification rules help to identify a CI is unique and CI exists in CMDB or not. It applies to a CI class and uses the CI’s attribute for identification
Unique attributes: Attribute or sets of attributes that make a CI unique like Name and Serial Number.
Required attributes: Attributes which cannot be empty like Company, Name.
What are reconciliation rules?
Reconciliation rules determine which sources can update the CMDB data and when it can be updated. If there are multiple sources then which source will update which attributes. It helps in CMDB correctness and blocks unauthorized sources to update CMDB.
What are data precedence order in reconciliation rules?
Rules which are configured for specific attributes have higher precedence over rules which are apply to all attributes.
Between two rules which apply to the same attribute with apply to all attributes, the rule which is directly for the class has precedence over the other.
Between two rules which apply to the same attribute to the same class with apply to all attributes, the precedence is determined with the priority.
Which role is needed to manage CMDB?
| Name | Description |
| cmdb_import_api_admin | CMDB Push API role for sending data into an import set staging table through the REST endpoint |
| cmdb_inst_admin | This role allows users to do all actions relevant to CMDB Integration Studio |
| cmdb_query_builder | Can access the CMDB Query Builder application to create, run and save queries on the CMDB |
| cmdb_query_builder_read | Can access the CMDB Query Builder application to run saved queries on the CMDB |
| cmdb_read | Role required to read data from CMDB hierarchy |
| ecmdb_admin | Can manage the Enterprise CMDB |
| sn_cmdb_admin | The highest level role for CMDB privileges. Provides full access to the CMDB data, tools, and UIs. Admin can set policies such as class manager, app service requirement, etc that editor cannot. |
| sn_cmdb_editor | CRUD access to CMDB records but not allowed to change policies such as data manager, class manager, etc |
| sn_cmdb_user | Read-only access to the CMDB data and basic UIs (e.g. reports, dashboards, etc). |
| sn_cmdb_workspace_user | Enable access to workspace and they may have the ability to in future look at query results, etc but don’t have read on itself. The control point in the future to ensure customers can control who gets to view workspace and contain visible w/out CMDB read. |
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Have you implemented discovery?
Here you can share your experiences with discovery implementation what were learning points and how to make it better, what was the scale etc.
Name types of discovery in ServiceNow?
There are two types
- Horizontal Discovery.
- Top-down Discovery.
Components of the discovery?
- Probes and sensors
- Patterns
Describe discovery with mid servers?
Best practices for CMDB implementation?
- Use OOB CI classes as much as possible.
- Avoid customization.
- Enable CMDB health dashboard.
- Create custom attributes on the right class/level.
- Identify CMDB population sources and automate as much as possible.
- Set rules to avoid duplicate, blank names.
- Identify owners who can manage CMDB.
- Use guided setup.
Which integrations you have done to populate CMDB?
You can share the tools which is used and how you have integrated them. Example SCCM, TADDM, Discovery, Service Mapping.
Other ServiceNow CMDB Interview Questions
What is a mid-server?
What is service mapping?
Describe CMDB architecture?
How does CMDB support event management?
Explain the process to integrate third-party monitoring sources with ServiceNow?
Describe the most challenging CMDB implementation you have done?
Common issues you have faced when implementing customers’ CMDB?
Benefits of ServiceNow discovery?
Asset vs CI with example
When to create manual CI’s?
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Let us know if something above needs to be corrected and also please share your experience on ServiceNow CMDB Interview questions that can help others candidates.