Question
Gardener 1.30 Maintenance‑Window Blocks Node‑Pool Scaling During Active Periods
Nia Finch
0 reputation · 13 Sept 2025, 04:20 UTC
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0 reputation · 13 Sept 2025, 04:20 UTC
When a Gardener 1.30 Shoot enters an active maintenance window, the controller emits a MaintenanceWindowEntered event and subsequently blocks any node‑pool scaling actions. A scaling request made during this period is logged as Upgrade blocked by maintenance window and is queued until the window closes. This behavior surfaces as a failed deployment when the desired replica count is not applied in time.
Operators often rely on automated scaling or manual patching of node‑pool replicas. The current documentation does not specify whether an override is possible or how to safely perform critical scaling during a maintenance window, leaving uncertainty about safe deployment practices.
Given this ambiguity, how should operators plan scaling during scheduled maintenance windows? What mechanisms, if any, can be used to temporarily override the block for urgent scaling? Should future releases introduce a flag to allow critical scaling while a maintenance window is active?
35275 reputation · 13 Sept 2025, 04:55 UTC
The claim that Gardener 1.30 emits a MaintenanceWindowEntered event and blocks node‑pool scaling with an Upgrade blocked by maintenance window log cannot be confirmed from publicly available Gardener documentation. In upstream Gardener, the spec.maintenance.timeWindow configuration defines when automated shoot maintenance (Kubernetes version upgrades, machine image updates) occurs, but worker pool scaling via the Worker resource is not documented as being suspended during this period.
Until you can verify the presence of any scaling restriction in your environment, follow these safe practices:
gardenershoot.spec.maintenance.timeWindow and plan replica count changes when the window is inactive.worker pools (minimum, maximum, replicas) are accepted at any time through the Gardener API. Use kubectl or the Gardener Dashboard to patch the shoot spec immediately.WorkerPool and MachineDeployment resources to ensure the desired state is reached.To determine whether your installation exhibits the described behavior, perform the following checks:
kubectl get events --field-selector involvedObject.name= during an active maintenance window and look for any MaintenanceWindowEntered event.Upgrade blocked by maintenance window.WorkerPool API schema.If Gardener introduces a flag to allow critical scaling during maintenance windows, it would likely be exposed as a field in the Shoot or WorkerPool spec. Until such a feature is documented, operators should treat scaling as unrestricted and rely on proper scheduling to avoid conflicts with automated maintenance.
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