• Kubernetes v1.35: Watch Based Route Reconciliation in the Cloud Controller Manager Up to and including Kubernetes v1.34, the route controller in Cloud Controller Manager (CCM) implementations built using thek8s.io/cloud-providerlibrary reconciles routes at a fixed interval. • This causes unnecessary API requests to the cloud provider when there are no changes to routes. • Other controllers implemented through the same library already use watch-based mechanisms, leveraging informers to avoid unnecessary API calls. • A new feature gate is being introduced in v1.35 to allow changing the behavior of the route controller to use watch-based informers. • The feature gateCloudControllerManagerWatchBasedRoutesReconciliationhas been introduced tok8s.io/cloud-providerin alpha stage bySIG Cloud Provider. • To enable this feature you can use–feature-gate=CloudControllerManagerWatchBasedRoutesReconciliation=truein the CCM implementation you are using.

Article Summaries:

  • Kubernetes v1.35 introduces a new feature gate, CloudControllerManagerWatchBasedRoutesReconciliation, that changes how the Cloud Controller Manager (CCM) reconciles routes. Previously, the route controller ran on a fixed interval, generating unnecessary API calls when routes were unchanged. The new watch‑based approach triggers reconciliation only when a node is added, removed, or its .spec.podCIDRs or .status.addresses change, and adds a random 12‑24 hour interval for additional checks. The change is in alpha and can be enabled with --feature-gate=CloudControllerManagerWatchBasedRoutesReconciliation=true. It does not alter existing route logic, so current configurations should remain stable. For details, see KEP‑5237.

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