Configuration Management Data Base – CMDB

Overview

The Configuration Management Database, or CMDB, is a data repository that contains all the assets and services managed by a company. This information includes servers, network devices, applications, services, and more. The benefits of the ServiceNow CMDB extend throughout the NOW Platform and enhance several Configuration Management capabilities.

Objectives:

• Explore best practices for configuring and implementing your CMDB.
• How the CI Class Manager provides a centralized place to create and edit CI classes.
• We will explore Identification and Reconciliation Framework for identifying and reconciling data from different data sources.
• Which rule are required to avoid duplicated or overloaded CIs.

CMDB Data View

Change Traceable:

Every change to CMDB data is fully traceable and logged by date and time.

For example: Source of data such as Manual, Discovery, SCCM, any third party tool, user, etc., which includes the new and previous value.

Query Builder

Query Builder feature provides a simple and intuitive way to query the CMDB for CIs and relationships across multiple CMDB tables

CMDB Dashboard

It provides a single view of the quality of data at the CMDB, CI class, and CI levels using completeness, correctness, and compliance scores.

 

Terminology which we use during Implementation

We have to be familiar with some terminology, we will be talking about those all the time during CMDB implementation.

1. Configuration Item (CI): A configuration item (CI) is any service component, infrastructure element, or other item that needs to be managed in order to ensure the successful delivery of services.
2. Attributes: Information that further describes a CI such as a name, serial number, manufacturer, operating system etc.
3. Relationship: Type: Relationship Types denotes the nature of relationship between a CI and another CI. It shows how the CIs are interconnected and interdependent with other CIs. For example, INSTALLED ON, Runs::Runs On.
4. Class: It is a table that contains and represents a specific type or group of CIs that share common attributes such as a Windows Server, Linux Server, Printer, Virtual Machine, Vehicle, and Animal etc.
5. Base Table: The core Configuration Item (cmdb_ci) table, which stores the basic attributes of all the CIs. All configuration item classes extend from this table including all hardware and applications.
6. CI Classification: CI classifications identify and characterize similar CI. Basically here we are classifying device type. If name start with “window” then it should go to cmdb_ci_win_server table and so on.
7. CI Reclassification: Ii is a CI whose class has been upgraded, downgraded, or switched. For example, a record upgraded from the cmdb_ci_server class to the Windows Server cmdb_ci_win_server class.
8. CI Class Upgrade: The CI class is updated to a class that is less generic in the class hierarchy, and the newly assigned class has additional attributes. For example, an upgrade occurs if a CI is moved from the Server cmdb_ci_server class to the Windows Server cmdb_ci_win_server class. In another words we can say CI moves from parent to child class.
9. CI Class Downgrade: Just Opposite to point 8.
10. CI Class Switch: If you are moving CI which has different branch. For Example: Moving Linux server to windows server.
11. Parent and Child Class: A table that extends another table is called a child class, and the table it extends is the parent class. A table can be both a parent and child class both extending and providing extensions for other tables. For example, the Server table extends the Computer table and the Windows Server table extends the Server table, thus making the Server table both a Parent and Child class.
12. Asset Vs CI: On the Now platform, when creating a hardware asset, a corresponding CI will be automatically created or when a CI is discovered for the first time and inserted into the CMDB, a corresponding asset record will be automatically created.
    • Asset: Often starts during the procurement process, but may be created when a discovery tool finds the CI for the first time
      • Is part of the financial lifecycle.
    • Configuration Item (CI): Often starts when a discovery tool find the CI for the first time, but may be created during the procurement process.
      • Is part of the technical operations.
13. Asset DB Vs CMDB:
    • Asset DB is inventory + financial data
    • CMDB is inventory + relationships
14. Application Service: A set of interconnected applications and hosts which are configured to offer a service to the organization. Application services can be internal, like an organization email system or customer-facing, like an organization website.

 

CMDB Table and Required Attribute Details

• Hardware – name, asset tag, installed date, status

• Computer – serial_number, ip_address, mac_address, name, Model id

• Network Adapter-serial_number, ip_address, mac_address, name, status, configuration item

• Wireless Access Point– serial_number, name, Model id

• Business service-Name, Business criticality, used for, operational status, service classification

• Ip Switch-serial_number, ip_address, mac_address, name, Model id

• Ip Router –serial_number, ip_address, mac_address, name, Model id

• Infrastructure Service- Name, version, operational status
• Disk- Name, Storage type, serial_number, Model id

• Application- Name, Operational status

• Software-name, virsion, manufaturer

CMDB Data Model