Configuration overrides

When you create a fabric intent or workload intent, the Fabric Services System prepares a set of configuration files for all of the affected nodes.

A configuration override allows you to specify a set of changes to the configuration files for one or more nodes. The Fabric Services System supports the following types of configuration overrides:

  • Global configuration overrides, which modify one or more node configurations and are associated with a fabric intent
  • Contextual configuration overrides, which alter one or more sub-interface or router configurations and are associated with a workload intent

Configuration overrides are strictly additive; they allow you to insert new or modify existing configuration data, but they cannot be used to remove any of the configuration data that the system creates based on the original fabric intent inputs.

Note: All configuration overrides, whether global or contextual overrides, are specific to the region in which they are created. An override that is created within one region is not visible within, or available to, other regions.

Order of applying overrides

A node could be the subject of several different overrides: global configuration overrides, contextual configuration overrides, and deviation-associated overrides.

To ensure that the result of any combination of overrides is predictable, the Fabric Services System applies overrides in a specific sequence to arrive at the final configuration for a particular node:
  1. The system begins with the normalized configuration for the node, based on the combination of a specific version of a fabric intent plus any workload intents that affect the node.
  2. Then the system applies any global configuration overrides that affect the node.
  3. Then the system applies any contextual configuration overrides that affect the node.
  4. Finally the system applies any deviation-associated configuration overrides that affect the node.