FR-CFG-004 — Environment Inheritance

Go to Crucible Configuration Management Requirements

Statement

Crucible SHALL derive each child Infrastructure Configuration from one identified parent Infrastructure Configuration while preserving inherited configuration values except where the child configuration explicitly overrides them.

Source Statement

The system SHALL support environment inheritance models.

Source

Crucible System Requirements Specification, Version 1.1 Draft, Functional Requirements, Configuration Management, FR-CFG-004.

Assessment

The source statement expresses the approved functional intent but does not provide all information required for deterministic verification.

The following Specification Discipline and Authoring findings apply:

The system does not use the defined system nameSupport is a weak verb that does not identify the behavior Crucible performsEnvironment inheritance model does not identify the inherited artifact, inheritance relationship, or resulting configurationThe source statement does not distinguish a parent Infrastructure Configuration from a child Infrastructure ConfigurationThe source statement does not identify whether a child configuration may inherit from one or more parent configurationsThe source statement does not identify which configuration values may be overriddenThe source statement does not identify how an override remains distinguishable from an inherited valueThe source statement does not define how inheritance conflicts are resolvedThe source statement does not identify how the resulting configuration preserves the relationship to its parentThe source statement does not identify the validation criteria applied to the resolved configurationThe normalized Statement replaces the weak verb with derive, identifies the parent and child Infrastructure Configurations, limits each child configuration to one identified parent, and requires explicit overrides for inherited values.

Validation, conflict detection, inheritance depth, multiple-parent inheritance, and resolved-configuration traceability require evaluation during the Configuration Management completeness review before allocation to this requirement or creation of derived requirements.

Rationale

Environment inheritance allows related Infrastructure Environments to share common configuration without duplicating the complete configuration for each environment.

A parent Infrastructure Configuration may define values common to a group of environments, such as:

Network structureSecurity settingsApproved Baseline referencesCommon infrastructure resourcesResource relationshipsLogging settingsCompliance settingsOperational constraintsA child Infrastructure Configuration inherits those values and explicitly identifies only the permitted differences required by the target environment.

For example, development, test, staging, and production environments may inherit common infrastructure intent while overriding values such as:

Resource capacityScaling limitsNetwork addressesEnvironment identifiersDeployment regionsAccess restrictionsRetention periodsCrucible preserves the distinction between inherited values and child-specific overrides.

This distinction allows an evaluator or operator to determine:

Which values originated in the parent configurationWhich values the child configuration overridesWhich parent configuration appliesWhich values form the resulting resolved configurationEnvironment inheritance supports:

Reduced configuration duplicationConsistent configuration across related environmentsControlled environment-specific variationConfiguration comparisonReduced configuration driftReproducibilityProvenanceAuditabilityTraceability

Applies To

This requirement applies to:

Parent Infrastructure ConfigurationsChild Infrastructure ConfigurationsEnvironment inheritanceInherited configuration valuesExplicit configuration overridesResolved configurationsInfrastructure EnvironmentsDeclarative ConfigurationInfrastructure BlueprintsBaselinesInfrastructure BaselinesConfiguration ManagementProvenanceAuditabilityReproducibilityTraceability

Verification

Verification SHALL confirm that each tested child Infrastructure Configuration identifies one parent Infrastructure ConfigurationVerification SHALL confirm that the child Infrastructure Configuration inherits configuration values from the identified parentVerification SHALL confirm that inherited values remain unchanged unless the child Infrastructure Configuration explicitly overrides themVerification SHALL confirm that each override identifies the inherited value that it replacesVerification SHALL confirm that values not explicitly overridden retain the values defined by the parent Infrastructure ConfigurationVerification SHALL confirm that the resulting resolved configuration distinguishes inherited values from child-specific overridesVerification SHALL confirm that modifying the child Infrastructure Configuration does not modify the parent Infrastructure ConfigurationVerification SHALL confirm that modifying the parent Infrastructure Configuration does not alter a previously recorded resolved configurationVerification SHALL confirm that the inheritance relationship remains identifiable in the resulting configuration recordVerification SHALL confirm that the resolved configuration satisfies the applicable acceptance criteriaVerification SHALL confirm that the configuration records preserve the applicable Provenance and TraceabilityVerification may include:

Parent configuration inspectionChild configuration inspectionInheritance relationship inspectionInherited-value comparisonOverride inspectionResolved-configuration comparisonParent immutability testsChild modification testsParent revision testsAcceptance criteria evaluationConfiguration record inspectionEnd-to-end CI/CD Pipeline testsThe verification record SHALL identify:

The tested child Infrastructure ConfigurationThe identified parent Infrastructure ConfigurationThe inherited configuration valuesThe explicitly overridden valuesThe resulting resolved configurationThe inheritance relationshipThe parent configuration revisionThe child configuration revisionThe applicable acceptance criteriaThe observed resultsThe applicable ProvenanceThe generated Evidence

Outgoing Traceability

This requirement refines:

This requirement operates within the conditions established by:

This requirement also relates to:

Referenced By

The wiki Backlinks function provides the current list of pages that reference FR-CFG-004.

Incoming traceability should be derived dynamically from backlinks rather than maintained as a duplicate manual list.

Backlinks identify incoming references but do not define the semantics of each relationship. Referencing pages should identify whether the relationship represents realization, refinement, verification, dependency, or another defined traceability relationship.

ConOps Relationship

The Crucible Concept of Operations describes the use of reusable and versioned configuration content within a CI/CD Pipeline workspace.

Environment inheritance allows the workflow to:

Select a common parent Infrastructure ConfigurationApply common configuration values to related environmentsApply explicit environment-specific overridesProduce a resolved configuration for the target environmentPreserve the relationship between the parent and child configurationsPerform Infrastructure DeploymentRecord the resolved configuration associated with the deploymentPreserve execution results and EvidenceThis model reduces duplicated configuration while preserving explicit and reviewable differences among related environments.

Delivery Phase

Phase 1 and subsequent phases

Implementation Status

Not Assessed

Implementation status requires verification that Crucible derives a child Infrastructure Configuration from one identified parent Infrastructure Configuration and preserves inherited values except where the child explicitly overrides them.

Requirement Status

Draft

The source System Requirements Specification identifies Version 1.1 as a draft.

Notes for Editors

This requirement page should retain the stable requirement identifier FR-CFG-004.

Changes to the Statement SHALL preserve the approved intent of the source requirement.

Material changes should receive review and should update the related outbound traceability, verification criteria, inheritance records, acceptance criteria, and source records.

The Source Statement should preserve the original wording from the controlling System Requirements Specification.

The Configuration Management completeness review should evaluate whether inheritance validation, conflict handling, inheritance depth, multiple-parent inheritance, override authorization, and resolved-configuration traceability require derived requirements.

Incoming traceability should use the wiki Backlinks function rather than a manually maintained list.

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