TIS0901 - Telemetry with Empty Providers Not Valid Without Default Providers

A Telemetry configuration with empty providers is not valid when the default providers in MeshConfig are also empty.

Recommendation: Ensure Telemetry Configuration References Valid Providers

To prevent undefined behavior in telemetry, always reference a valid provider in Telemetry configurations or ensure default providers are set in MeshConfig.

Examples

1. Telemetry Object Without Specified Providers

   apiVersion: telemetry.istio.io/v1alpha1
   kind: Telemetry
   metadata:
     name: telemetry-without-providers
     namespace: example-namespace
   spec:
     accessLogging: []
     metrics: []

   Explanation: The Telemetry object does not specify any access logging or metrics providers, and the default providers in the MeshConfig are also empty. This leads to undefined behavior since Istio cannot determine which provider to use for telemetry.

Recommendation

Correct the reference to a valid provider or set up default providers.

1. Add a Valid Provider to the Telemetry Configuration

   Update the Telemetry configuration to reference valid logging and metrics providers.

   apiVersion: telemetry.istio.io/v1alpha1
   kind: Telemetry
   metadata:
     name: telemetry-with-providers
     namespace: example-namespace
   spec:
     accessLogging:
     - provider: "default"
     metrics:
     - provider: "default"

   Explanation: Adding a valid provider to the Telemetry object ensures that Istio knows which provider to use for collecting telemetry data, preventing issues related to undefined behavior.

2. Set Up Default Providers in MeshConfig

   Alternatively, update the MeshConfig to define default providers for telemetry.

   apiVersion: install.istio.io/v1alpha1
   kind: IstioOperator
   metadata:
     name: istio-control-plane
     namespace: istio-system
   spec:
     meshConfig:
       defaultProviders:
         accessLogging: ["default"]
         metrics: ["default"]

   Explanation: Setting up default providers in MeshConfig ensures that, even if specific Telemetry configurations do not specify providers, Istio will still use the default providers for telemetry collection.