フィーチャー ゲートは、機能を有効にするうえで Kubernetes API とは別のメカニズムであり、GKE クラスタによって Kubernetes API とは異なる方法で管理されています。アルファ クラスタでは、Kubernetes のアルファ版 API がすべて有効になります。アルファ クラスタのフィーチャー ゲートを有効または無効にしても、Kubernetes API が有効な状態には影響しません。ただし、Kubernetes API と Kubernetes フィーチャー ゲートの中には互いに連携して動作するものがあります。フィーチャー ゲートを無効にすると、これらに関連する API で問題が発生する可能性があります。特定のフィーチャー ゲートと API との接続を検証します。
[[["わかりやすい","easyToUnderstand","thumb-up"],["問題の解決に役立った","solvedMyProblem","thumb-up"],["その他","otherUp","thumb-up"]],[["わかりにくい","hardToUnderstand","thumb-down"],["情報またはサンプルコードが不正確","incorrectInformationOrSampleCode","thumb-down"],["必要な情報 / サンプルがない","missingTheInformationSamplesINeed","thumb-down"],["翻訳に関する問題","translationIssue","thumb-down"],["その他","otherDown","thumb-down"]],["最終更新日 2025-09-01 UTC。"],[],[],null,["# Alpha clusters\n\n[Standard](/kubernetes-engine/docs/concepts/choose-cluster-mode)\n\n*** ** * ** ***\n\nThis page provides an overview of how alpha clusters work in\nGoogle Kubernetes Engine (GKE). Access to alpha features and APIs works differently\nwith alpha clusters than with other types of GKE clusters. You\ncan [create an alpha\ncluster](/kubernetes-engine/docs/how-to/creating-an-alpha-cluster) or learn more\n[about cluster configuration\nchoices](/kubernetes-engine/docs/concepts/types-of-clusters).\n| **Warning:** Don't use alpha clusters or alpha features for production workloads. Alpha clusters expire after 30 days and don't receive security updates. You must migrate your data from alpha clusters before they expire. GKE does not automatically save data stored on alpha clusters. For more information, see [Limitations](#limitations).\n\nYou can experiment with Kubernetes alpha features by creating an *alpha\ncluster*. Alpha clusters are short-lived clusters that run stable Kubernetes\nreleases. All Kubernetes APIs, including alpha APIs, are enabled. By default,\nalpha clusters have all alpha feature gates enabled that are available with the\nKubernetes version. Some beta feature gates are enabled, depending on the\ndefault for Kubernetes. You can also selectively enable or disable specific\nalpha or beta feature gates during cluster creation. Alpha clusters are designed\nfor advanced users and early adopters to experiment with workloads that take\nadvantage of new features before those features are production-ready.\n\n### Limitations\n\nAlpha clusters have the following limitations:\n\n- Not covered by the [GKE SLA](/kubernetes-engine/sla)\n- Can't be upgraded\n - You must disable node auto-upgrade and auto-repair on alpha clusters\n- Can't be enrolled in a [release channel](/kubernetes-engine/docs/concepts/release-channels)\n- Are automatically deleted after 30 days\n- Don't receive security updates\n- Not supported with Windows Server node pools\n- Have additional [limitations for enabling feature gates with alpha clusters](#limitations-alpha-feature-gate)\n\n### Difference between alpha clusters and alpha GKE versions\n\nAlpha clusters don't necessarily run \"alpha\" versions of GKE. The\nterm *alpha cluster* means that alpha APIs are enabled regardless of the version\nof Kubernetes the cluster runs. Periodically, Google offers customers the\nability to test and validate GKE versions that are not generally\navailable. These early-access versions can be run as alpha clusters or as\nclusters without the Kubernetes alpha APIs enabled.\n\nFeature gates and alpha clusters\n--------------------------------\n\nFeature gates are a set of key-value pairs that toggle Kubernetes features. With\nalpha clusters, GKE enables the following:\n\n- **Alpha feature gates**: all feature gates at the alpha stages that are available with the Kubernetes version of your cluster\n- **Beta feature gates**: the feature gates at the beta stages that are available with the Kubernetes version of your cluster, and which are enabled by default by open source Kubernetes\n\nFor more information about which feature gates are available for a specific\nKubernetes version, and which beta features are enabled by default (`true`), see\n[Feature gates for Alpha or Beta features](https://kubernetes.io/docs/reference/command-line-tools-reference/feature-gates/#feature-gates-for-alpha-or-beta-features)\nin the Kubernetes documentation. However, you can selectively enable or disable\nspecific feature gates, modifying the default values set by GKE.\n\nFeature gates are a distinct mechanism for feature enablement from Kubernetes\nAPIs, and are managed differently by GKE clusters. With alpha\nclusters, all Kubernetes alpha APIs are enabled. If you enable or disable a\nfeature gate for an alpha cluster, the enablement of Kubernetes APIs isn't\naffected. However, some Kubernetes APIs and Kubernetes feature gates work\ntogether, so disabling feature gates might cause issues with related APIs.\nVerify the connection between specific feature gates and APIs.\n\nFor more information about how GKE works with feature gates, see\n[Feature gates](/kubernetes-engine/docs/concepts/feature-gates).\n\nTo enable a cluster with a specific feature gate configuration, use the\n`--alpha-cluster-feature-gates` flag during cluster creation with the\nGoogle Cloud CLI. When you include this flag, you can modify which alpha and beta\nfeature gates are enabled or disabled. For more information, see [Create an\nalpha\ncluster](/kubernetes-engine/docs/how-to/creating-an-alpha-cluster#create_an_alpha_cluster).\n\n### Limitations for enabling feature gates with alpha clusters\n\nWhen you enable feature gates with alpha clusters, understand the following\nadditional limitations:\n\n- You can only create alpha clusters with specific feature gates by using the gcloud CLI. Cluster creation with the Google Cloud console or Terraform isn't supported.\n- Kubernetes alpha features that require additional configuration beyond enabling the feature gate aren't supported.\n- You can selectively enable or disable alpha or beta feature gates, but all Kubernetes alpha APIs are enabled.\n\nLatest Kubernetes alpha features\n--------------------------------\n\nMost Kubernetes releases contain new alpha features that you can test in alpha\nclusters. For a full list of Kubernetes releases and the features they include,\nsee the [Kubernetes changelog](https://github.com/kubernetes/kubernetes/blob/master/CHANGELOG/README.md).\n\n### About feature stages\n\nNew Kubernetes features are introduced in four stages: early development, alpha,\nbeta, and stable.\n\nTo provide stability and production quality, GKE clusters other\nthan alpha clusters enable only features that are *beta or higher*.\nGKE doesn't enable alpha features on other types of\nGKE clusters because the features aren't production-ready or\nupgradeable.\n\nBecause GKE automatically upgrades the Kubernetes control plane\nand, by default, the worker nodes, enabling alpha features in production can\njeopardize the reliability of the cluster if there are breaking changes in a new\nversion.\n\nTo learn more about the stages of Kubernetes features, see [Alpha, Beta, and\nStable\nVersions](https://github.com/kubernetes/community/blob/master/contributors/devel/sig-architecture/api_changes.md#alpha-beta-and-stable-versions)\nin the Kubernetes documentation.\n\nTo learn more about determining which features are enabled for a given\nGKE control plane version, see [Feature\ngates](/kubernetes-engine/docs/concepts/feature-gates).\n\nWhat's next\n-----------\n\n- Learn more [about cluster configuration choices](/kubernetes-engine/docs/concepts/types-of-clusters).\n- [Create an alpha cluster](/kubernetes-engine/docs/how-to/creating-an-alpha-cluster).\n- [Read the GKE overview](/kubernetes-engine/docs/concepts/kubernetes-engine-overview)."]]
