Relationship governance rules

  • Release version: Xanadu
  • Updated August 1, 2024
  • 2 minutes to read
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    Summary of Relationship governance rules

    Relationship governance rules in ServiceNow ensure consistency and validity when modeling relationships between configuration items (CIs) in the CMDB. They prevent invalid relationship types or directions between specific CI types, helping maintain a reliable and standardized CMDB structure. These rules address inconsistencies caused by different applications like Discovery and Service Mapping creating relationships that represent the same entities differently.

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    Key Features

    • CMDB dependent relationship rules: These include hosting and containment rules used for CI identification. They can be viewed and modified in the CI Class Manager under Dependent Relationship for specific CI classes.
    • Suggested relationships: Based on entries in the Suggested Relationship table, these rules are used in the CI relationship editor and managed through the CI Class Manager under Suggested Relationships.
    • Reference rules: Primarily used by Cloud Management to define valid combinations of referencing and referenced CIs in service definitions.
    • Built-in valid relationships: The system includes predefined valid relationships between certain CI classes, such as between endpoints and applications or hardware.
    • Inheritance support: Relationship rules support class inheritance, allowing relationships valid at a parent class level to apply to subclasses as well.
    • Multiple relationship types allowed: More than one relationship type can exist between the same two CI types, enabling rich and nuanced CI relationship modeling.

    Key Outcomes

    Using relationship governance rules helps ServiceNow customers maintain a consistent and valid CMDB by:

    • Preventing invalid or inconsistent CI relationships.
    • Supporting inheritance to simplify relationship validations across CI subclasses.
    • Allowing multiple valid relationship types between CI pairs for comprehensive modeling.
    • Providing visibility into relationship compliance through the Relationship Health dashboard, which reports on relationships not conforming to governance rules.

    This governance ensures accurate service modeling and supports effective discovery, service mapping, and cloud management processes.

    Relationship governance rules is a set of relationship rules used to ensure consistency and validity in modeling relationships between configuration items (CIs) in the CMDB. Use relationship governance rules to prevent the selection of relationship types or directions that are not allowed between specific CI types.

    Different applications such as Discovery and Service Mapping create relationships between CIs. Each application might use inconsistent relationship type or direction to represent the same entity, resulting in multiple views of the same CIs. Relationship governance rules define what are valid relationship types and valid directions between pairs of CI types resulting in valid and consistent relationships in the CMDB.

    Relationship governance rules consist of:
    • CMDB dependent relationship rules: Rules (hosting and containment rules) that are used for CI identification. You can view and modify dependent relationship rules in the CI Class Manager, after selecting a class from the class hierarchy and clicking Dependent Relationship.
    • Suggested relationships: Rules that are based on existing suggested relationships in the Suggested Relationship [cmdb_rel_type_suggest] table. Suggested relationships are used in the CI relationship editor. You can view and modify suggested relationships in the CI Class Manager, after selecting a class from the class hierarchy and clicking Suggested Relationships.
    • Reference rules: Rules that are used mostly by Cloud Management to represent all the possible valid combinations of pairs of referencing and referenced CIs in the service definition.
    • Built-in valid relationships: The following relationships are pre-defined in the base system as valid relationships:
      • cmdb_ci_endpoint -> Applicative Flow To::Applicative Flow From -> cmdb_ci_endpoint
      • cmdb_ci_endpoint -> Implement End Point To::Implement End Point From -> cmdb_ci
      • cmdb_ci -> Use End Point To::Use End Point From -> cmdb_ci_endpoint

    General behavior

    • Relationship governance rules support inheritance.

      For example, suppose that the suggested relationship cmdb_ci_appl Runs On::Runs cmdb_ci_hardware exists. Then a Runs On::Runs relationship between a cmdb_ci_appl_dot_net CI and a cmdb_ci_windows_server CI is valid. That is because .Net Application class inherits from the Application class and the Windows Server class inherits from the Hardware class.

    • Duplicate relationship governance rules are not allowed.
    • Relationship governance rules are not domain separated.
    • It is allowed to have more than one relationship type between the same two CI types.
      For example, the following relationships are valid:
      • cmdb_ci_appl Depends On::Used by cmdb_ci_service
      • cmdb_ci_appl Receives data from::Sends data to cmdb_ci_service

    Reports

    A relationship between CIs is considered valid if it conforms to any of the relationship governance rules. Use the Relationship Health dashboard to view reports about relationships health including relationships compliance with relationship governance rules. The 'Relationships not compliant with all relationship rules' report shows CI relationships that are not compliant with any of the relationship governance rules.