Interview Help!! How to answer the below question perfectly !!

[sanyalshubh]

How does the Identification and Reconciliation process impact CI creation in CMDB, and how would you verify if it's causing failures in this scenario?

[Ravi Gaurav · Accepted solution]

Hi @sanyalshubh 

The Identification and Reconciliation (I&R) engine in ServiceNow CMDB ensures data integrity and prevents duplicate Configuration Items (CIs). When new CI data is introduced via discovery, integrations, or manual input, I&R determines whether to create, update, or ignore the incoming data. The process works as follows:

1. Identification Rules:

   • The system checks if an incoming record matches existing CIs using predefined identification rules.
   • If a match is found, the record is updated.
   • If no match is found, a new CI is created.
   • If multiple matches are found, an error occurs, preventing duplicate or conflicting data.

2. Reconciliation Rules:

   • Defines which source has the authority to update specific attributes.
   • Prevents unauthorized overwrites from less authoritative sources.

3. Duplicate Prevention:

   • Ensures a single source of truth by avoiding duplicate CIs.
   • If strict identification rules exist, legitimate new CIs may be rejected due to rule mismatches.

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How to Verify if I&R is Causing CI Creation Failures:

If you suspect that the I&R process is blocking CI creation, follow these steps:

1. Check Identification Rules:

   • Navigate to Configuration > CI Class Manager > Identification Rules.
   • Verify if the rules match the incoming data.
   • If rules are too strict, adjust the criteria accordingly.

2. Review Identification Logs:

   • Navigate to CMDB Identification and Reconciliation > Identification Log.
   • Look for errors such as:
     • Multiple Matches Found (indicating duplicate CIs).
     • No Matches Found (indicating failure to identify existing CIs).
     • Authorization Issues (when a source lacks permission to update fields).

3. Check CI Reconciliation Status:

   • Go to CMDB Reconciliation > Reconciliation Logs.
   • Identify if the "Target Rejected" status appears.
   • Check which data source is authoritative for conflicting attributes.

4. Validate Discovery or Import Data:

   • If CIs are coming from Discovery or Integration, inspect the Raw Import Table (imp_* tables).
   • Ensure required attributes are mapped correctly to match identification rules.

5. Test Manual CI Creation:

   • Try manually creating a CI via the CMDB CI form.
   • If manual creation succeeds but automated creation fails, I&R is likely interfering.

6. Use CMDB Health Dashboard:

   • Navigate to CMDB Dashboard > Health KPIs.
   • Review metrics like Duplicate CIs and Orphan CIs to detect anomalies.