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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  • The Graduated/Deprecated feature gate table also lists deprecated and withdrawn features.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

Feature Default Stage Since Until
HVPA false Alpha 0.31
HVPAForShootedSeed false Alpha 0.32
DefaultSeccompProfile false Alpha 1.54
CoreDNSQueryRewriting false Alpha 1.55
IPv6SingleStack false Alpha 1.63
MutableShootSpecNetworkingNodes false Alpha 1.64
MachineControllerManagerDeployment false Alpha 1.73
MachineControllerManagerDeployment true Beta 1.81 1.81
MachineControllerManagerDeployment true GA 1.82
ShootForceDeletion false Alpha 1.81
APIServerFastRollout true Beta 1.82
UseGardenerNodeAgent false Alpha 1.82

Feature Gates for Graduated or Deprecated Features

Feature Default Stage Since Until
NodeLocalDNS false Alpha 1.7
NodeLocalDNS Removed 1.26
KonnectivityTunnel false Alpha 1.6
KonnectivityTunnel Removed 1.27
MountHostCADirectories false Alpha 1.11 1.25
MountHostCADirectories true Beta 1.26 1.27
MountHostCADirectories true GA 1.27
MountHostCADirectories Removed 1.30
DisallowKubeconfigRotationForShootInDeletion false Alpha 1.28 1.31
DisallowKubeconfigRotationForShootInDeletion true Beta 1.32 1.35
DisallowKubeconfigRotationForShootInDeletion true GA 1.36
DisallowKubeconfigRotationForShootInDeletion Removed 1.38
Logging false Alpha 0.13 1.40
Logging Removed 1.41
AdminKubeconfigRequest false Alpha 1.24 1.38
AdminKubeconfigRequest true Beta 1.39 1.41
AdminKubeconfigRequest true GA 1.42 1.49
AdminKubeconfigRequest Removed 1.50
UseDNSRecords false Alpha 1.27 1.38
UseDNSRecords true Beta 1.39 1.43
UseDNSRecords true GA 1.44 1.49
UseDNSRecords Removed 1.50
CachedRuntimeClients false Alpha 1.7 1.33
CachedRuntimeClients true Beta 1.34 1.44
CachedRuntimeClients true GA 1.45 1.49
CachedRuntimeClients Removed 1.50
DenyInvalidExtensionResources false Alpha 1.31 1.41
DenyInvalidExtensionResources true Beta 1.42 1.44
DenyInvalidExtensionResources true GA 1.45 1.49
DenyInvalidExtensionResources Removed 1.50
RotateSSHKeypairOnMaintenance false Alpha 1.28 1.44
RotateSSHKeypairOnMaintenance true Beta 1.45 1.47
RotateSSHKeypairOnMaintenance (deprecated) false Beta 1.48 1.50
RotateSSHKeypairOnMaintenance (deprecated) Removed 1.51
ShootMaxTokenExpirationOverwrite false Alpha 1.43 1.44
ShootMaxTokenExpirationOverwrite true Beta 1.45 1.47
ShootMaxTokenExpirationOverwrite true GA 1.48 1.50
ShootMaxTokenExpirationOverwrite Removed 1.51
ShootMaxTokenExpirationValidation false Alpha 1.43 1.45
ShootMaxTokenExpirationValidation true Beta 1.46 1.47
ShootMaxTokenExpirationValidation true GA 1.48 1.50
ShootMaxTokenExpirationValidation Removed 1.51
WorkerPoolKubernetesVersion false Alpha 1.35 1.45
WorkerPoolKubernetesVersion true Beta 1.46 1.49
WorkerPoolKubernetesVersion true GA 1.50 1.51
WorkerPoolKubernetesVersion Removed 1.52
DisableDNSProviderManagement false Alpha 1.41 1.49
DisableDNSProviderManagement true Beta 1.50 1.51
DisableDNSProviderManagement true GA 1.52 1.59
DisableDNSProviderManagement Removed 1.60
SecretBindingProviderValidation false Alpha 1.38 1.50
SecretBindingProviderValidation true Beta 1.51 1.52
SecretBindingProviderValidation true GA 1.53 1.54
SecretBindingProviderValidation Removed 1.55
SeedKubeScheduler false Alpha 1.15 1.54
SeedKubeScheduler false Deprecated 1.55 1.60
SeedKubeScheduler Removed 1.61
ShootCARotation false Alpha 1.42 1.50
ShootCARotation true Beta 1.51 1.56
ShootCARotation true GA 1.57 1.59
ShootCARotation Removed 1.60
ShootSARotation false Alpha 1.48 1.50
ShootSARotation true Beta 1.51 1.56
ShootSARotation true GA 1.57 1.59
ShootSARotation Removed 1.60
ReversedVPN false Alpha 1.22 1.41
ReversedVPN true Beta 1.42 1.62
ReversedVPN true GA 1.63 1.69
ReversedVPN Removed 1.70
ForceRestore Removed 1.66
SeedChange false Alpha 1.12 1.52
SeedChange true Beta 1.53 1.68
SeedChange true GA 1.69 1.72
SeedChange Removed 1.73
CopyEtcdBackupsDuringControlPlaneMigration false Alpha 1.37 1.52
CopyEtcdBackupsDuringControlPlaneMigration true Beta 1.53 1.68
CopyEtcdBackupsDuringControlPlaneMigration true GA 1.69 1.72
CopyEtcdBackupsDuringControlPlaneMigration Removed 1.73
ManagedIstio false Alpha 1.5 1.18
ManagedIstio true Beta 1.19
ManagedIstio true Deprecated 1.48 1.69
ManagedIstio Removed 1.70
APIServerSNI false Alpha 1.7 1.18
APIServerSNI true Beta 1.19
APIServerSNI true Deprecated 1.48 1.72
APIServerSNI Removed 1.73
HAControlPlanes false Alpha 1.49 1.70
HAControlPlanes true Beta 1.71 1.72
HAControlPlanes true GA 1.73 1.73
HAControlPlanes Removed 1.74
FullNetworkPoliciesInRuntimeCluster false Alpha 1.66 1.70
FullNetworkPoliciesInRuntimeCluster true Beta 1.71 1.72
FullNetworkPoliciesInRuntimeCluster true GA 1.73 1.73
FullNetworkPoliciesInRuntimeCluster Removed 1.74
DisableScalingClassesForShoots false Alpha 1.73 1.78
DisableScalingClassesForShoots true Beta 1.79 1.80
DisableScalingClassesForShoots true GA 1.81 1.81
DisableScalingClassesForShoots Removed 1.82
ContainerdRegistryHostsDir false Alpha 1.77 1.85
ContainerdRegistryHostsDir true Beta 1.86 1.86
ContainerdRegistryHostsDir true GA 1.87 1.87
ContainerdRegistryHostsDir true Removed 1.88
WorkerlessShoots false Alpha 1.70 1.78
WorkerlessShoots true Beta 1.79 1.85
WorkerlessShoots true GA 1.86
WorkerlessShoots true Removed 1.88

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

Feature Relevant Components Description
HVPA gardenlet, gardener-operator Enables simultaneous horizontal and vertical scaling in garden or seed clusters.
HVPAForShootedSeed gardenlet Enables simultaneous horizontal and vertical scaling in managed seed (aka "shooted seed") clusters.
DefaultSeccompProfile gardenlet, gardener-operator Enables the defaulting of the seccomp profile for Gardener managed workload in the garden or seed to RuntimeDefault.
CoreDNSQueryRewriting gardenlet Enables 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.
IPv6SingleStack gardener-apiserver, gardenlet Allows 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.
MutableShootSpecNetworkingNodes gardener-apiserver Allows 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.
MachineControllerManagerDeployment gardenlet Enables Gardener to take over the deployment of the machine-controller-manager. If enabled, all registered provider extensions must support injecting the provider-specific MCM sidecar container into the deployment via the controlplane webhook.
ShootForceDeletion gardener-apiserver Allows forceful deletion of Shoots by annotating them with the confirmation.gardener.cloud/force-deletion annotation.
APIServerFastRollout gardenlet Enables fast rollouts for Shoot kube-apiservers on the given Seed. When enabled, maxSurge for Shoot kube-apiserver deployments is set to 100%.
UseGardenerNodeAgent gardenlet Enables the gardener-node-agent instead of the cloud-config-downloader for shoot worker nodes.