istio_metadata/v0

Overview

The istio_metadata interface lets an Istio control plane charm share information about its installation with charms that need to interoperate with Istio. The provider publishes a small piece of metadata (currently the root namespace where Istio is installed); requirers read it to configure their integration with Istio.

Direction

This is a unidirectional interface where the provider sends data and the requirer only receives data. There is no data sent back from the requirer side.

        flowchart TD
    Provider -- root_namespace --> Requirer
    

Behavior

• Provider (Istio control plane charm): Publishes the metadata to the application data bag, typically on leader_elected and on this relation’s relation_joined events. Only the leader unit may write the application data bag.

• Requirer: Consumes the metadata when the relation is populated. The requirer is expected to use limit: 1 for this relation, since the metadata describes a single Istio installation.

Relation Data

[Pydantic Schema]

On the provider side, the application data bag must contain the following field:

• root_namespace (string, required): The root namespace where Istio is installed (for example, istio-system).

Provider

Example

  application-data:
    root_namespace: istio-system

Requirer

N/A