Certified Implementation Specialist CIS-Discovery Book

Variables are used in discovery patterns to store and manipulate data that is collected or calculated during the discovery process. There are three kinds of variables used in discovery patterns12:

CI attributes: These are variables that correspond to the attributes of the configuration item (CI) type that the pattern is discovering. For example, name, serial_number, manufacturer, etc. CI attributes are used to populate the CI record in the CMDB with the information gathered by the pattern.

Temporary: These are variables that are created and used within the pattern, but are not stored in the CMDB. For example, $result, $output, $user_var, etc. Temporary variables are used to store and manipulate data such as the output of a command, the value of a parameter, or the result of a calculation.

Global: These are variables that are defined in the global scope and can be accessed by any pattern. For example, $mid, $target, $ip_address, etc. Global variables are used to store and access data that is common to all patterns, such as the MID Server, the target device, or the IP address.

The Pattern Designer is a graphical tool that allows users to create and edit horizontal discovery patterns. The Pattern Designer has three main sections: the left section shows the CI type and the pattern type, the middle section shows the pattern steps and the flow diagram, and the far-right section shows the details of the selected step or operation. The far-right section can display the following tabs, depending on the type of step or operation selected12:

Operations: This tab shows the list of available operations that can be added to the pattern, such as Execute Command, Parse File, Set Parameter Value, etc. Operations are the basic building blocks of a pattern that perform specific actions on the target device or the MID Server.

CI Attributes: This tab shows the list of attributes that can be set or updated for the CI type of the pattern, such as name, serial number, manufacturer, etc. CI attributes are used to populate the CI record in the CMDB with the information collected by the pattern.

Temporary Variables: This tab shows the list of temporary variables that can be created or used by the pattern, such as $result, $output, $user_var, etc. Temporary variables are used to store and manipulate data within the pattern, such as the output of a command, the value of a parameter, or the result of a calculation.

CMDB Dashboard: This tab shows the CMDB dashboard that displays the CI record and its related lists, such as relationships, identification rules, sensors, etc. The CMDB dashboard is used to preview and verify the outcome of the pattern on the CI record in the CMDB.

 The Service Account for the MID Server must have the Log on as service right on the Windows platform. This right allows the MID Server to run as a Windows service and communicate with the ServiceNow instance. The Service Account does not need to have local or domain admin rights, as these are not required for the MID Server functionality. The MID Server User Role is a role on the ServiceNow instance, not on the Windows platform, and it is used to control the access and permissions of the MID Server on the instance.