Modify patterns using extension sections

Enable patterns to search for additional attributes and modify pattern discovery logic defined in identification sections by using extension sections.

Before you begin

If your ServiceNow instance uses domain separation and you have access to the global domain, select the domain to which the business service belongs from the domain picker (). The selected domain must be a domain without any child domains.

Basic knowledge of programming is desirable.

Role required: pd_admin

About this task

Patterns can be of infrastructure or application type. Infrastructure patterns are used only by Discovery for creating lists of devices. Application patterns serve both Service Mapping and Discovery that use the same application patterns for their purposes. Each pattern including its identification and connection sections is an individual file. There are also reusable sequences of discovery steps referred to as shared libraries. Each shared library is an individual file, but it is always part of the infrastructure or application pattern and is not used as a standalone pattern. Records for both patterns and shared libraries reside in the Discovery Patterns [sa_pattern] table.

To modify the discovery logic in identification sections without changing the identification sections themselves, you can add extension sections to the pattern. Every extension section consists of a shared library, either new or existing.

Adding an extension section to a pattern.
When you create or modify a shared library in the extension section, you save changes only to the shared library, not to the pattern containing this extension section.
Attention: The changes to the shared library affect all patterns using this shared library.

The MID Server runs extension sections after identification sections and only if at least one identification section completes successfully.

If there are more than one extension sections associated with this pattern, define the order in which the MID Server runs these extension sections.

You can deactivate shared libraries, so that patterns using them, skip steps in deactivated shared libraries. For more information, see Discovery Configuration Console.


  1. Navigate to Pattern Designer > Discovery Patterns and open the required pattern from the pattern list.

    The pattern can be of the Infrastructure or Application type.

  2. To define discovery steps for the new extension section.
    1. Click New under Extension section.
    2. Enter the name of this extension section.
    3. Click Done.
      The pattern form displays the new section under Extension section.
    4. Click the name of the new extension section.

      The Pattern Designer opens showing the Steps tree on the left.

      If no discovery steps have been identified for this pattern, the Untitled Step appears in the Steps tree in the left pane of the window.

    5. Define discovery steps.
  3. To use an existing shared library for the new extension section:
    1. Click Add under Extension section.
    2. Select the shared library from the name list.
  4. If there are more than one extension sections, define the order in which the MID Server runs the extension section.
    1. Select the check box next to the extension section.
    2. Click Edit under Extension section.
    3. Enter a number that determines the order in the Order field.
      If there is only one extension section, its order is 1 by default.
      The section with the lowest order number is used first.
    4. Click Done.

What to do next

Click Debug to run the newly created extension section. Pattern Designer runs extension sections after running identification sections.