Shoot cluster supported Kubernetes versions and specifics

Shoot Kubernetes Minor Version Upgrades

Breaking changes may be introduced with new Kubernetes versions. This documentation describes the Gardener specific differences and requirements for upgrading to a supported Kubernetes version. For Kubernetes specific upgrade notes the upstream Kubernetes release notes, changelogs and release blogs should be considered before upgrade.

Upgrading to Kubernetes v1.33

• A new deny-all NetworkPolicy is deployed into the kube-system namespace of the Shoot cluster. Shoot owners that run workloads in the kube-system namespace are required to explicitly allow their expected Ingress and Egress traffic in kube-system via NetworkPolicies.
• The Shoot’s field .spec.kubernetes.kubeControllerManager.podEvictionTimeout is forbidden. Shoot owners should use the .spec.kubernetes.kubeAPIServer.defaultNotReadyTolerationSeconds and .spec.kubernetes.kubeAPIServer.defaultUnreachableTolerationSeconds fields.
• The Shoot’s field .spec.kubernetes.clusterAutoscaler.maxEmptyBulkDelete is forbidden. Shoot owners should use the .spec.kubernetes.clusterAutoscaler.maxScaleDownParallelism field.

Upgrading to Kubernetes v1.32

Tip

It is recommended to migrate from OIDC to StructuredAuthentication before updating to Kubernetes v1.32 in order to avoid not being able to revert the change.

• The Shoot’s spec.kubernetes.kubeAPIServer.oidcConfig field is forbidden.
  • Shoot owners that have used oidcConfig or a (Cluster)OpenIDConnectPreset resource are recommended to migrate to StructuredAuthentication. More information about StructuredAuthentication can be found in the Structured Authentication documentation.

Upgrading to Kubernetes v1.31

• The Shoot’s spec.kubernetes.kubeAPIServer.oidcConfig.clientAuthentication field is forbidden.
• The Shoot’s .spec.kubernetes.kubelet.systemReserved and .spec.provider.workers[].kubernetes.kubelet.systemReserved fields are forbidden. Shoot owners should use the .spec.kubernetes.kubelet.kubeReserved and .spec.provider.workers[].kubernetes.kubelet.kubeReserved fields.

Upgrading to Kubernetes v1.30

• The kubelet UnlimitedSwap behavior, configured in the Shoot’s .spec.{kubernetes,provider.workers[]}.kubelet.memorySwap.swapBehavior fields, can no longer be used.