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Identification Rules

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In this lesson, you will learn:

  • What an identification rule contains
  • Independent and dependent classes
  • How to read the Hardware rule

🔁 Quick look back: Last time: How IRE Identifies an Existing CI. You learned how IRE matches discovered data to an existing CI.

1 The Problem: Spreadsheet CIs Have Nothing to Match On

SNWR’s hand-made CIs have names, but no serial numbers and no network adapter records. So:

  • The strongest identifier, serial number, is empty.
  • Matching depends on names only.

🎯 The problem: SNWR’s spreadsheet CIs have little to match on.

👉 The fix: Understand identification rules, so you know which fields matter for matching.

Table of Hardware rule entries in priority order.
Figure 1. A typical Hardware identification rule, tried in order.

2 Inside an identification rule

Key term: Identification rule

The rule IRE uses to recognise CIs of a class.

Key term: Identifier entry

One way to match, such as serial number. Entries have a priority.

Key term: Independent class

Can be identified on its own, like a server.

Key term: Dependent class

Needs its parent to be identified, like software on a server.

Rules are set in CI Class Manager. Most classes inherit a rule from a parent class, such as Hardware.

3 What this means for SNWR

  • Until the first scan, SNWR’s CIs can only match on name.
  • After the first scan, serial numbers fill in, and matching gets stronger.
  • Dependent CIs, like PostgreSQL, are matched through their server.

⚠️ Heads up: Don’t change baseline identification rules without a strong reason. Add a rule only for new classes, like the SNWR Mail Archiver.

4 Project Clear View: How We Implemented It

📍 Situation: The design must say how SNWR’s servers will be matched.

🧭 Decision: Use the baseline Hardware rule, and prepare names so the first match works.

🛠️ Steps we took:

  1. Read the Hardware rule in CI Class Manager on snwrdev.
  2. Confirmed SNWR’s CIs can only match on name today.
  3. Decided to keep the baseline rules for all standard classes.
  4. Noted that the archiver class will need its own rule.

✅ What we verified:

  • Hana agreed not to change baseline rules.
  • The archiver rule is on the design list.

📁 Evidence: Identification notes for design decision DD-D06 (see Solution Design › Designing CMDB and Identification Decisions).

5 Quick recap

  • An identification rule has entries tried in priority order.
  • Independent classes match on their own. Dependent ones need their parent.
  • The Hardware rule tries serial number first, then name.
  • Keep baseline rules. Add rules only for new classes.

6 Check yourself

Think of your answer first. Then tap to check.

1 What is an identifier entry? Show answer

One way to match a CI, such as serial number, with a priority.

2 Is PostgreSQL on snwr-db-01 independent or dependent? Show answer

Dependent. It’s identified through its server.

3 Why did SNWR keep the baseline rules? Show answer

They work well once serial numbers are filled, and changing them adds risk.

Nice work! You can read an identification rule. 🎉
Next up: Discovery Source and Data Sources

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