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CMDB & Configuration Items

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In this lesson, you will learn:

  • What the CMDB is and why it matters
  • What a configuration item (CI) is
  • How CIs get into the CMDB

1 A map of everything IT runs

When the SNWR email service goes down, the first question is: “What does email run on?” Which servers? Which database? Who owns them? The CMDB answers that. 🗺️

Key term: CMDB

Configuration Management Database. The part of ServiceNow that stores the IT things a company runs, and how they connect.

Key term: Configuration item (CI)

One thing tracked in the CMDB, like a server, laptop, database, application, or network switch. All CIs extend the base table cmdb_ci.

The SNWR email service and what it depends on. SNWR Email, an application service, depends on the Exchange application, which runs on two Windows servers, mail01 and mail02. The servers use the MAILDB database and sit behind a load balancer. An incident about email can point to the SNWR Email CI, so agents see everything it relies on.
Figure 1. CIs and their links show what depends on what.

2 Why the CMDB matters

Process How it uses the CMDB
Incident The Configuration item field shows what’s broken, and what else might be affected
Change See what a change could impact before you approve it
Problem Spot one CI causing many incidents
Assets and costs Know what you own and who owns it

3 How CIs get in

  • Discovery: scans the network (through a MID Server) and creates CIs automatically.
  • Service Graph Connectors: bring CIs in from other tools, like cloud or endpoint management systems.
  • Import sets: load CIs from a spreadsheet (Chapter 43).
  • Manually: create a CI by hand. Fine for a few, not for thousands.

📝 Note: Explore CIs in Configuration > Servers, Configuration > Computers, and more, or use the CMDB Workspace for a modern view.

⚠️ Heads up: A CMDB is only useful if it’s correct. Old or duplicate CIs lead people to wrong answers. Chapter 44.4 covers keeping it healthy.

⭐ Remember: CMDB = the IT things you run + how they connect. Each thing is a CI, built on cmdb_ci.

4 Let’s try it: explore CIs

  1. Go to Configuration > Servers > All. Open any server. What fields do you see?
  2. Open an incident and look at its Configuration item field. Click the preview icon.
  3. Type cmdb_ci.list in the filter navigator. How many CIs are there in total?

5 Quick recap

  • The CMDB stores IT things and how they connect
  • Each thing is a configuration item (CI)
  • All CIs extend cmdb_ci
  • CIs come from Discovery, Service Graph Connectors, imports, or by hand
  • Incident, change, and problem all use the CMDB

6 Check yourself

Think of your answer first. Then tap to check.

1 What does CMDB stand for? Show answer

Configuration Management Database.

2 Which base table do all CIs extend? Show answer

cmdb_ci.

3 Which ServiceNow feature scans the network to find CIs? Show answer

Discovery.

Nice work! You finished this lesson. 🎉

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