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Priority and inheritance

When an object has one or more Profiles assigned, Infrahub uses a deterministic process to decide which value applies to each attribute or relationship. This page explains both the inheritance flow and the priority system that resolves conflicts when multiple Profiles apply.

Inheritance mechanism​

Profile inheritance follows a sophisticated model:

Node Creation/Update
       ↓
Check if Profiles assigned (If created from a template, inherit its Profiles)
       ↓
For each attribute/relationship:
  - Is value explicitly set on node? → Use node value
  - Is default value being used? → Check Profiles
       ↓
Check Profiles by priority (lowest number first)
       ↓
Use first Profile-defined value found
       ↓
If no Profile defines it → Use schema default

This mechanism ensures predictable behavior while maintaining flexibility.

Profile priority system​

Understanding priority values​

Profile priority uses numeric values where lower numbers have higher priority. This might seem counterintuitive but aligns with common networking conventions (like route metrics).

Example scenario:

Profile A: priority = 1000 (default)
Profile B: priority = 500  (higher priority)
Profile C: priority = 1500 (lower priority)

Inheritance order: B → A → C

Priority in practice​

Consider a node with three Profiles defining MTU:

  • Base profile (priority 1000): MTU = 1500
  • Department profile (priority 500): MTU = 9000
  • Legacy profile (priority 1500): MTU = 1400

The node inherits MTU = 9000 from the department profile (highest priority).

Design rationale​

The priority system enables:

  • Hierarchical configuration: Organization-wide → Department → Team → Special cases
  • Controlled overrides: Higher-priority Profiles override lower-priority ones
  • Flexible composition: Combine multiple Profiles without conflicts