Traversal rules in Service Mapping
Summarize
Summary of Traversal Rules in Service Mapping
Traversal rules are essential for identifying and mapping relationships between configuration items (CIs) in ServiceNow's Service Mapping, creating detailed application service maps. These rules connect relevant CIs based on predefined relationships, enhancing service visualization and accuracy.
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Key Features
- Parent Type: The starting CI class for mapping related CIs.
- Relationship: Defines the link between Parent and Child CIs, influencing the traversal direction based on the Is Reverse setting.
- Child Type: The CI class that contains related items mapped from the Parent CI.
- Priority Level: Determines the order of rule application, with lower numbers having higher precedence.
- Is Reverse: A flag indicating if the mapping process starts from the Child CI instead of the Parent CI.
Key Outcomes
Properly configured traversal rules ensure accurate mapping, even for CIs not directly tagged. Service Mapping comes with predefined rules for easier initial configuration, and you can also create custom rules tailored to your organization’s needs. Note that only five traversal rules can be active in tag-based discovery by default, but this limit can be adjusted via the svctraversal.rules.active system property.
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 Service Mapping.
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.