Create a Stackstate monitor

[jvanz]

Stackstate has the concept of Monitors. Each monitor keeps an eye on an aspect of Kubernetes resources. For example, it can check if the replica size matches the actual number of replicas running. We could add a Kubewarden monitor, which will notify the user if a resource is not compliant with a Kubewarden policy. In other words, the monitor will expose the audit scanner results in the Stackstate UI for a specific resource.

Stackstate allows users to add a custom monitor. These custom monitors are based on the metrics available in Prometheus. Therefore, to proceed, we should find a way to identify audit scanner-generated metrics. We could leverage the Policy Reporter features to generate and export metrics to Prometheus.

Stackstate also has external monitors where applications can send data directly to it. This may be another option for how to implement this integration.

Acceptance Criteria

• Define the best approach to add the Kubewarden monitor in Stackstate:
  • Using Prometheus metrics
  • Using external monitors
• If the decision is made to use Prometheus metrics, check if our metrics need additional fields to work properly with Stackstate, and fix any issues that arise.
• If the decision is made to use external monitors, document the implementation.
• Add tests to cover the integration with Stackstate.