Create or edit a CI identification rule

Identification rules are used to uniquely identify CIs in the CMDB, as part of the identification and reconciliation process. Each table in the CMDB can be associated with a single identification rule.

Before you begin

Role required: admin, or itil_admin (on top of itil)
Note: Users with the itil role have read access to the CI identification rules.

About this task

In a CI identification rule, specify identifier entries and related entries that uniquely identify the CI. Review the following before creating identification rules:

Procedure

  1. Use the CI Class Manager:
    1. Navigate to Configuration > CI Class Manager.
    2. Select a class in the Class Hierarchy.
    3. On the right, click Advanced and expand Correctness.
    4. Select CI Metadata Editor, and click the Identification tab.
  2. Or, navigate to Configuration > Identification/Reconciliation > CI Identifiers.
  3. Click New, Add New Rule, or select an existing rule.
  4. Complete the form.
    Table 1. Identifier form
    Field Description
    Name Name of CI identifier.
    Applies to Class that this CI identifier applies to.
    Description Description of the CI identifier.
    Independent Check box indicating that the CI identifier can identify the CI independently of other CIs.

    See Identification rules and Effective usage of CMDB Identification for more information.

  5. Click Submit, and then click the identification rule to load its related lists.
  6. In the Identifier Entries related list, click New or open an existing entry to specify criteria for matching the CI. Fill out the form, and then click Submit.
    Table 2. Identifier Entry form
    Field Description
    Active Check box that specifies the identifier entry is active.
    Criterion attributes The set of attributes to uniquely identify the CI. Attributes can belong to the current class, or to a parent class.

    Click the lock icon to view, add, or remove attributes from the identification rule.

    It is not possible to add reference fields as a criterion attribute. Reference fields store sys_ids that point to a record in another table, and thus is considered a weak criterion attribute (in terms of uniqueness) for the current table.

    Identifier The CI identifier to which this identifier entry belongs to. By default it is set to the identifier you previously selected.
    Priority Priority of the identifier entry. Identifier entries are applied based on priority. Rules with lower priority numbers are given higher priority. Identifier entries of identical priorities are applied randomly.

    It is recommended that you keep gaps between the priority numbers, so you can assign the unused priority numbers to new entries without modifying the existing priority order.

    Search on table
    The lookup table:
    • For a regular identifier entry: Select the same table as the table specified in Applies to on the Identifier form.
    • For a lookup identifier entry: Select a table that is different from the Applies to table specified on the Identifier form. Also, the lookup table must have a reference field to cmdb_ci, otherwise the identifier entry is considered invalid.
    Allow fallback to parent's rules Check box to specify that the identification rules of the CI's parent are used if a match is not found for this identification rule. Applies only for dependent identification rules.
    Allow null attribute Check box to allow null values for criterion and unique attributes.
    Optional condition Use the Add Filter Condition and the Add "OR" Clause buttons to construct a filter to narrow the set of records that will be searched for a matching CI. Applied only to lookup based identification.
    Enforce exact count match (Lookup) Check box for specifying that for lookup identification, match only on exact lookup records count match.
  7. In the Related Entries related list, click New or open an existing entry to specify a related entry for matching the related item. Fill out the form, and then click Submit.
    Table 3. Related Entry form
    Field Description
    Identifier The CI identifier for which this related entry belongs to. By default it is set to the identifier you previously selected.
    Related table A related table that references the CI that is being matched.
    Referenced field A referenced field in Related table that should store the referenced CI. This field always reference the cmdb_ci table, or a descendent of the cmdb_ci table.
    Criterion attributes The set of attributes to uniquely identify the related item. Attributes can belong to the current class, or to a parent class.

    Click the lock icon to view, add, or remove attributes from the identification rule.

    Optional condition Use the Add Filter Condition and the Add "OR" Clause buttons to construct a filter to narrow the set of records that will be searched for a matching related item.
    Active Check box that specifies that the related entry is active.
    Allow null attribute Check box to allow null values for criterion and unique attributes.
    Priority Priority of the related entry for the specified Related table. Rules with lower priority numbers are given higher priority while matching a related item for specific related table. Related entries for the specified related table with identical priorities are applied randomly.

    It is recommended that you keep gaps between the priority numbers, so you can assign the unused priority numbers to new entries without modifying the existing priority order.

Example

For example, the pre-defined Hardware Rule applies to the Hardware [cmdb_ci_hardware] table. It has an identifier entry with the criterion attribute Serial Number, Serial Number Type and its Search on table field is set to Serial Number.

The following payload snippet adds a CI to the cmdb_ci_linux_server class, that is a child of the Hardware class. It also shows how you can add related items in the payload for which you should create Related Entries on the CI Identifier page for the Hardware [cmdb_ci_hardware] table:

{
    "items": [
        {
            "className": "cmdb_ci_linux_server",
            "lookup": [
                {
                    "className": "cmdb_serial_number",
                    "values": {
                        "serial_number": "VMware-42 21 e3 da 44 14 5a a6-56 48 2b 0a 28 53 42 4c",
                        "serial_number_type": "system",
                        "valid": "true"
                    }
                },
                {
                    "className": "cmdb_serial_number",
                    "values": {
                        "serial_number": "4221E3DA-4414-5AA6-5648-2B0A2853424C",
                        "serial_number_type": "uuid",
                        "valid": "true"
                    }
                },                }
            ],

    “related": [
                {
                    "className": "cmdb_ci_ucs_chassis",
                    "values": {
                        “name": “chassis1",
                        “category": “category1",
                        “short_description": “My Chassis 1"
                    }
                },
                {
                    "className": "cmdb_ci_ucs_chassis",
                    "values": {
                        “name": "chassis2",
                        "category": "category2",
                        "short_description": "My Chassis 2"
                    }
                },    }
     ],

            "values": {
                ......
                "name": "xpolog2.lab3",
                "os_name": "Linux",
                "output": "Linux xpolog2.lab3 2.6.32-431.el6.x86_64 #1 SMP Fri Nov 22 03:15:09 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux",
                "serial_number": "VMware-42 21 e3 da 44 14 5a a6-56 48 2b 0a 28 53 42 4c",
                "sys_class_name": "cmdb_ci_linux_server"
            }
        }
    ]
}
                         

When the Hardware Rule is applied, the Serial Number [cmdb_serial_number] table is searched for a match with the values specified within the lookup key. Unless Enforce exact count match (Lookup) is checked, it is not necessary for every lookup key to return a match, as long as there is at least one match. If all matches reference the same CI, then that CI is considered to be the existing CI record. If no match is found, then the identification search continues to the next rule entry. If after all the rules are exhausted without finding a match, a new CI record is created in the database.