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Feature Gates in Gardener

This page contains an overview of the various feature gates an administrator can specify on different Gardener components.

Overview

Feature gates are a set of key=value pairs that describe Gardener features. You can turn these features on or off using the component configuration file for a specific component.

Each Gardener component lets you enable or disable a set of feature gates that are relevant to that component. For example, this is the configuration of the gardenlet component.

The following tables are a summary of the feature gates that you can set on different Gardener components.

  • The “Since” column contains the Gardener release when a feature is introduced or its release stage is changed.
  • The “Until” column, if not empty, contains the last Gardener release in which you can still use a feature gate.
  • If a feature is in the Alpha or Beta state, you can find the feature listed in the Alpha/Beta feature gate table.
  • If a feature is stable you can find all stages for that feature listed in the Graduated/Deprecated feature gate table.
  • The Graduated/Deprecated feature gate table also lists deprecated and withdrawn features.

Feature Gates for Alpha or Beta Features

FeatureDefaultStageSinceUntil
HVPAfalseAlpha0.31
HVPAForShootedSeedfalseAlpha0.32
DefaultSeccompProfilefalseAlpha1.54
CoreDNSQueryRewritingfalseAlpha1.551.95
CoreDNSQueryRewritingtrueBeta1.96
CoreDNSQueryRewritingtrueGA1.97
IPv6SingleStackfalseAlpha1.63
MutableShootSpecNetworkingNodesfalseAlpha1.641.95
MutableShootSpecNetworkingNodestrueBeta1.96
MutableShootSpecNetworkingNodestrueGA1.97
ShootForceDeletionfalseAlpha1.811.90
ShootForceDeletiontrueBeta1.91
UseNamespacedCloudProfilefalseAlpha1.92
ShootManagedIssuerfalseAlpha1.93
VPAForETCDfalseAlpha1.941.96
VPAForETCDtrueBeta1.97
VPAAndHPAForAPIServerfalseAlpha1.95

Feature Gates for Graduated or Deprecated Features

FeatureDefaultStageSinceUntil
NodeLocalDNSfalseAlpha1.7
NodeLocalDNSRemoved1.26
KonnectivityTunnelfalseAlpha1.6
KonnectivityTunnelRemoved1.27
MountHostCADirectoriesfalseAlpha1.111.25
MountHostCADirectoriestrueBeta1.261.27
MountHostCADirectoriestrueGA1.27
MountHostCADirectoriesRemoved1.30
DisallowKubeconfigRotationForShootInDeletionfalseAlpha1.281.31
DisallowKubeconfigRotationForShootInDeletiontrueBeta1.321.35
DisallowKubeconfigRotationForShootInDeletiontrueGA1.36
DisallowKubeconfigRotationForShootInDeletionRemoved1.38
LoggingfalseAlpha0.131.40
LoggingRemoved1.41
AdminKubeconfigRequestfalseAlpha1.241.38
AdminKubeconfigRequesttrueBeta1.391.41
AdminKubeconfigRequesttrueGA1.421.49
AdminKubeconfigRequestRemoved1.50
UseDNSRecordsfalseAlpha1.271.38
UseDNSRecordstrueBeta1.391.43
UseDNSRecordstrueGA1.441.49
UseDNSRecordsRemoved1.50
CachedRuntimeClientsfalseAlpha1.71.33
CachedRuntimeClientstrueBeta1.341.44
CachedRuntimeClientstrueGA1.451.49
CachedRuntimeClientsRemoved1.50
DenyInvalidExtensionResourcesfalseAlpha1.311.41
DenyInvalidExtensionResourcestrueBeta1.421.44
DenyInvalidExtensionResourcestrueGA1.451.49
DenyInvalidExtensionResourcesRemoved1.50
RotateSSHKeypairOnMaintenancefalseAlpha1.281.44
RotateSSHKeypairOnMaintenancetrueBeta1.451.47
RotateSSHKeypairOnMaintenance (deprecated)falseBeta1.481.50
RotateSSHKeypairOnMaintenance (deprecated)Removed1.51
ShootMaxTokenExpirationOverwritefalseAlpha1.431.44
ShootMaxTokenExpirationOverwritetrueBeta1.451.47
ShootMaxTokenExpirationOverwritetrueGA1.481.50
ShootMaxTokenExpirationOverwriteRemoved1.51
ShootMaxTokenExpirationValidationfalseAlpha1.431.45
ShootMaxTokenExpirationValidationtrueBeta1.461.47
ShootMaxTokenExpirationValidationtrueGA1.481.50
ShootMaxTokenExpirationValidationRemoved1.51
WorkerPoolKubernetesVersionfalseAlpha1.351.45
WorkerPoolKubernetesVersiontrueBeta1.461.49
WorkerPoolKubernetesVersiontrueGA1.501.51
WorkerPoolKubernetesVersionRemoved1.52
DisableDNSProviderManagementfalseAlpha1.411.49
DisableDNSProviderManagementtrueBeta1.501.51
DisableDNSProviderManagementtrueGA1.521.59
DisableDNSProviderManagementRemoved1.60
SecretBindingProviderValidationfalseAlpha1.381.50
SecretBindingProviderValidationtrueBeta1.511.52
SecretBindingProviderValidationtrueGA1.531.54
SecretBindingProviderValidationRemoved1.55
SeedKubeSchedulerfalseAlpha1.151.54
SeedKubeSchedulerfalseDeprecated1.551.60
SeedKubeSchedulerRemoved1.61
ShootCARotationfalseAlpha1.421.50
ShootCARotationtrueBeta1.511.56
ShootCARotationtrueGA1.571.59
ShootCARotationRemoved1.60
ShootSARotationfalseAlpha1.481.50
ShootSARotationtrueBeta1.511.56
ShootSARotationtrueGA1.571.59
ShootSARotationRemoved1.60
ReversedVPNfalseAlpha1.221.41
ReversedVPNtrueBeta1.421.62
ReversedVPNtrueGA1.631.69
ReversedVPNRemoved1.70
ForceRestoreRemoved1.66
SeedChangefalseAlpha1.121.52
SeedChangetrueBeta1.531.68
SeedChangetrueGA1.691.72
SeedChangeRemoved1.73
CopyEtcdBackupsDuringControlPlaneMigrationfalseAlpha1.371.52
CopyEtcdBackupsDuringControlPlaneMigrationtrueBeta1.531.68
CopyEtcdBackupsDuringControlPlaneMigrationtrueGA1.691.72
CopyEtcdBackupsDuringControlPlaneMigrationRemoved1.73
ManagedIstiofalseAlpha1.51.18
ManagedIstiotrueBeta1.19
ManagedIstiotrueDeprecated1.481.69
ManagedIstioRemoved1.70
APIServerSNIfalseAlpha1.71.18
APIServerSNItrueBeta1.19
APIServerSNItrueDeprecated1.481.72
APIServerSNIRemoved1.73
HAControlPlanesfalseAlpha1.491.70
HAControlPlanestrueBeta1.711.72
HAControlPlanestrueGA1.731.73
HAControlPlanesRemoved1.74
FullNetworkPoliciesInRuntimeClusterfalseAlpha1.661.70
FullNetworkPoliciesInRuntimeClustertrueBeta1.711.72
FullNetworkPoliciesInRuntimeClustertrueGA1.731.73
FullNetworkPoliciesInRuntimeClusterRemoved1.74
DisableScalingClassesForShootsfalseAlpha1.731.78
DisableScalingClassesForShootstrueBeta1.791.80
DisableScalingClassesForShootstrueGA1.811.81
DisableScalingClassesForShootsRemoved1.82
ContainerdRegistryHostsDirfalseAlpha1.771.85
ContainerdRegistryHostsDirtrueBeta1.861.86
ContainerdRegistryHostsDirtrueGA1.871.87
ContainerdRegistryHostsDirRemoved1.88
WorkerlessShootsfalseAlpha1.701.78
WorkerlessShootstrueBeta1.791.85
WorkerlessShootstrueGA1.86
WorkerlessShootsRemoved1.88
MachineControllerManagerDeploymentfalseAlpha1.73
MachineControllerManagerDeploymenttrueBeta1.811.81
MachineControllerManagerDeploymenttrueGA1.821.91
MachineControllerManagerDeploymentRemoved1.92
APIServerFastRollouttrueBeta1.821.89
APIServerFastRollouttrueGA1.901.91
APIServerFastRolloutRemoved1.92
UseGardenerNodeAgentfalseAlpha1.821.88
UseGardenerNodeAgenttrueBeta1.89
UseGardenerNodeAgenttrueGA1.901.91
UseGardenerNodeAgentRemoved1.92

Using a Feature

A feature can be in Alpha, Beta or GA stage. An Alpha feature means:

  • Disabled by default.
  • Might be buggy. Enabling the feature may expose bugs.
  • Support for feature may be dropped at any time without notice.
  • The API may change in incompatible ways in a later software release without notice.
  • Recommended for use only in short-lived testing clusters, due to increased risk of bugs and lack of long-term support.

A Beta feature means:

  • Enabled by default.
  • The feature is well tested. Enabling the feature is considered safe.
  • Support for the overall feature will not be dropped, though details may change.
  • The schema and/or semantics of objects may change in incompatible ways in a subsequent beta or stable release. When this happens, we will provide instructions for migrating to the next version. This may require deleting, editing, and re-creating API objects. The editing process may require some thought. This may require downtime for applications that rely on the feature.
  • Recommended for only non-critical uses because of potential for incompatible changes in subsequent releases.

Please do try Beta features and give feedback on them! After they exit beta, it may not be practical for us to make more changes.

A General Availability (GA) feature is also referred to as a stable feature. It means:

  • The feature is always enabled; you cannot disable it.
  • The corresponding feature gate is no longer needed.
  • Stable versions of features will appear in released software for many subsequent versions.

List of Feature Gates

FeatureRelevant ComponentsDescription
HVPAgardenlet, gardener-operatorEnables simultaneous horizontal and vertical scaling in garden or seed clusters.
HVPAForShootedSeedgardenletEnables simultaneous horizontal and vertical scaling in managed seed (aka “shooted seed”) clusters.
DefaultSeccompProfilegardenlet, gardener-operatorEnables the defaulting of the seccomp profile for Gardener managed workload in the garden or seed to RuntimeDefault.
CoreDNSQueryRewritinggardenletEnables automatic DNS query rewriting in shoot cluster’s CoreDNS to shortcut name resolution of fully qualified in-cluster and out-of-cluster names, which follow a user-defined pattern. Details can be found in DNS Search Path Optimization.
IPv6SingleStackgardener-apiserver, gardenletAllows creating seed and shoot clusters with IPv6 single-stack networking enabled in their spec (GEP-21). If enabled in gardenlet, the default behavior is unchanged, but setting ipFamilies=[IPv6] in the seedConfig is allowed. Only if the ipFamilies setting is changed, gardenlet behaves differently.
MutableShootSpecNetworkingNodesgardener-apiserverAllows updating the field spec.networking.nodes. The validity of the values has to be checked in the provider extensions. Only enable this feature gate when your system runs provider extensions which have implemented the validation.
ShootForceDeletiongardener-apiserverAllows forceful deletion of Shoots by annotating them with the confirmation.gardener.cloud/force-deletion annotation.
UseNamespacedCloudProfilegardener-apiserverEnables usage of NamespacedCloudProfiles in Shoots.
ShootManagedIssuergardenletEnables the shoot managed issuer functionality described in GEP 24.
VPAForETCDgardenlet, gardener-operatorEnables VPA for etcd-main and etcd-events, regardless of HVPA enablement.
VPAAndHPAForAPIServergardenlet, gardener-operatorEnables an autoscaling mechanism for kube-apiserver of shoot or virtual garden clusters, and the gardener-apiserver. They are scaled simultaneously by VPA and HPA on the same metric (CPU and memory usage). The pod-trashing cycle between VPA and HPA scaling on the same metric is avoided by configuring the HPA to scale on average usage (not on average utilization) and by picking the target average utilization values in sync with VPA’s allowed maximums. The feature gate takes precedence over the HVPA feature gate when they are both enabled.