Traversal rules in Service Mapping
Summarize
Summary of Traversal rules in Service Mapping
Traversal rules in Service Mapping enable ServiceNow customers to identify and map relationships between configuration items (CIs) to create detailed and accurate application service maps. These rules leverage predefined relationships within the Configuration Management Database (CMDB) to connect related CIs, even when those CIs are not directly tagged. This capability enhances the accuracy and comprehensiveness of service maps and visualizations.
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Key Features
- Parent Type: Defines the CI class as the starting point for mapping related CIs.
- Relationship: Specifies the association between Parent and Child CIs, directing how the mapping traverses.
- Child Type: Identifies the target CI class related to the Parent CI.
- Priority Level: Establishes the order of rule application; lower numbers indicate higher precedence.
- Is Reverse: Determines the traversal direction—whether mapping starts from the Parent CI or from the Child CI instead.
Traversal rules must be configured in the correct order because tag-based discovery depends on these rules to identify mappable CIs accurately.
Configuration and Management
Service Mapping comes with predefined traversal rules to simplify initial setup. Customers can customize traversal rules to meet specific organizational requirements. The rules are managed by the Service Mapping administrator via the Traversal Rules for Application Services [svctraversalrules] table.
By default, up to five traversal rules can participate in tag-based discovery. This limit can be increased by adjusting the sysproperty svctraversal.rules.active system property.
Practical Benefits
By properly configuring traversal rules, customers enable tag-based discovery to map complex relationships between CIs effectively, resulting in more accurate and comprehensive service maps. This improved mapping helps with better visualization, impact analysis, and management of services within the ServiceNow platform.
Traversal rules identify and map relationships between configuration items to create comprehensive application service maps. They connect relevant configuration items based on predefined relationships, promoting accurate service mapping and visualization.
Traversal rules facilitate comprehensive service mapping by identifying related configuration items (CIs) through specific relationships that exist in the Configuration Management Database (CMDB). These rules support the mapping of related CIs even when they aren’t directly tagged, providing a more accurate service map.
Components of traversal rules
When configuring traversal rules, it’s essential to add them in the correct order, as tag-based discovery uses these rules to identify CIs that can be mapped.
The Service Mapping administrator (service_mapping_admin) manages traversal rules in the Traversal Rules for Application Services [svc_traversal_rules] table. When configuring these rules, the following key components are considered:
- Parent Type: The CI class that serves as the starting point for mapping related configuration items that belong to the Child class as specified by the traversal rule.
- Relationship: The specific association or link between the Parent CI and Child CI that determines how they’re related in the service mapping context. The direction of the traversal depends on the Is Reverse setting.
- Child Type: The CI class that contains the related configuration items being mapped from the Parent CI class as specified by the traversal rule.
- Priority Level: The level that specifies the order in which traversal rules are applied, with lower numbers taking precedence over higher numbers.
- Is Reverse: A flag that determines the direction of traversal for the relationship between Parent CI and Child CI. When selected, the mapping process starts from the Child CI instead of the Parent CI.Note:To promote accurate mapping, configure traversal rules with the correct priority levels, as tag-based discovery relies on these rules to identify mappable CIs.
Configuring traversal rules
Service Mapping includes predefined traversal rules, simplifying the initial configuration. These rules provide a starting point for your tag-based service mapping setup. For details on the specific predefined rules, see Predefined traversal rules for application services.
In addition to these predefined traversal rules, you can configure custom traversal rules to meet your organization's specific needs. For detailed instructions on how to configure traversal rules, including information on the required fields and settings, see Traversal Rules for Application Services form completion.
By default, you can only have five traversal rules participate in tag-based discovery. However, you can adjust this limit by configuring the sys_property svc_traversal.rules.active system property to enable more active traversal rules.