This article was originally published with the wrong date. It was later republished, dated the 15th of May 2026. Kubernetes v1.36 introduces a new alpha counter metric route_controller_route_sync_total to the Cloud Controller Manager (CCM) route controller implementation at k8s.io/cloud-provider . This metric increments each time routes are synced with the cloud provider. A/B testing watch-based route reconciliation This metric was added to help operators validate the CloudControllerManagerWatchBasedRoutesReconciliation feature gate introduced in Kubernetes v1.35 . That feature gate switches the route controller from a fixed-interval loop to a watch-based approach that only reconciles when nodes actually change. This reduces unnecessary API calls to the infrastructure provider, lowering pressure on rate-limited APIs and allowing operators to make more efficient use of their available quota. To A/B test this, compare route_controller_route_sync_total with the feature gate disabled (default) versus enabled. In clusters where node changes are infrequent, you should see a significant drop in the sync rate with the feature gate turned on. Example: expected behavior With the feature gate disabled (the default fixed-interval loop), the counter increments steadily regardless of whether any node changes occurred: # After 10 minutes with no node changes route_controller_route_sync_total 60

After 20 minutes, still no node changes

route_controller_route_sync_total 120 With the feature gate enabled (watch-based reconciliation), the counter only increments when nodes are actually added, removed, or updated: # After 10 minutes with no node changes route_controller_route_sync_total 1

After 20 minutes, still no node changes — counter unchanged

route_controller_route_sync_total 1

A new node joins the cluster — counter increments

route_controller_route_sync_total 2 The difference is especially visible in stable clusters where nodes rarely change. Where can I give feedback? If you have feedback, feel free to reach out through any of the following channels: The #sig-cloud-provider channel on Kubernetes Slack The KEP-5237 issue on GitHub The SIG Cloud Provider community page for other communication channels How can I learn more? For more details, refer to KEP-5237 .