Configuration Drift detection

Configuration Drift

Configuration drift is a commonly used term to describe a change that takes place in an environment. Drift is an issue as it causes systems and parts of a system which supposed to be consistent, to become inconsistent and unpredictable. In our case, configuration drift is a change of a resource deployed by Sveltos down the managed clusters.

Sveltos allows users to set the sync mode within a ClusterProfile to ContinuousWithDriftDetection. It enables Sveltos to monitor the state of managed clusters and detect configuration drift for any of the resources deployed by a ClusterProfile.

apiVersion: config.projectsveltos.io/v1alpha1
kind: ClusterProfile
metadata:
  name: deploy-kyverno
spec:
  syncMode: ContinuousWithDriftDetection
  ...

When Sveltos detects a configuration drift, it will automatically re-sync the cluster state back to its original state which is described in the management cluster. Sveltos deploys a service in each managed cluster and configures it with a list of Kubernetes resources deployed for each ClusterProfile in SyncModeContinuousWithDriftDetection mode.

The service starts a watcher for each GroupVersionKind with at least one resource to watch. When any watched resources are modified (labels, annotations, spec or rules sections), the service notifies the management cluster about potential configuration drifts. The management cluster then reacts by redeploying affected ClusterProfiles.

This way, Sveltos ensures that the systems are always consistent and predictable, preventing unexpected issues caused by the configuration drifts.