Create a Discovery legacy identifier

If your system is configured to use legacy identifiers, you can create new identifiers to examine the attributes from specific tables that extend tables in the default Discovery rules.

About this task

All new instances use identifiers from the CMDB Identification and Reconciliation framework. Upgrades from pre-Geneva versions still preserve the legacy identifiers, but you can switch to the new identifiers using a property: glide.discovery.use_cmdb_identifiers. If you upgraded from a pre-Geneva version, you must manually add this property and set it to true to use the new identifiers. If you upgraded from Geneva or later releases, this property is available in the System Properties [sys_properties] table. To preserve functionality in custom legacy identifiers, convert them to the new CMDB identifier rules format before enabling this property. The system does not reconfigure your custom identifiers to the new framework automatically.
Note: When Service Mapping is active, the new identifiers from the CMDB Identification and Reconciliation framework are always used regardless of the property value.

The default identifiers provided with Discovery should be adequate for most discoveries. However, if you need to discover data from a child table, such as Linux Server [cmdb_ci_linux_server], you can create a custom legacy identifier and select the exact criteria you want to add to the CMDB.

Procedure

  1. Navigate to Discovery Definition > CI Identification > Identifiers.
  2. Click New.
  3. Fill out the unique fields provided by the identifier form.
    Table 1. Identifier form fields
    Field Input Fields
    Applies to Select the ServiceNow table of the device class for this identifier. For example, if the class is Printer, then the table is cmdb_ci_printer.
    Order Configure the order in which the identification criteria are evaluated. An example might be serial number - 910, network name - 920, and computer name - 930.
    Script Create the conditions that determine what Discovery should do when the results are returned from a search of the CMDB for this identifier. For example, you might want to stop Discovery if two or more CIs in the CMDB match this identifier. Or you might want to evaluate additional identifiers even after a match has been established with this identifier. Use the scripting methods described below to tell Discovery how to respond.

    The completed Discovery identifier form looks like this:

    Figure 1. Discovery identifier form