主體別名 (SAN) 是 SSL 憑證的一項功能，可讓您定義憑證保護的網域名稱和子網域。在 Google Distributed Cloud 叢集上，Kubernetes API 伺服器憑證的預設 SAN 包括控制層節點的 IP 和 VIP 位址，以及 Kubernetes DNS 名稱。使用自訂 API 伺服器憑證額外 SAN 功能，您可以將其他網域、子網域和 IP 位址新增為叢集的 Kubernetes API 伺服器憑證 SAN。
Control Plane Node Pool Status:Anthos Bare Metal Version:1.28.0-gke.435Anthos Bare Metal Versions:1.28.0-gke.435:3Conditions:...Last Transition Time:2023-11-15T18:23:49ZObserved Generation:1Reason:ReconcilingStatus:TrueType:Reconciling
變更傳播至每個控制層節點上的 Kubernetes API 伺服器後，節點集區就會準備就緒。
Control Plane Node Pool Status:Anthos Bare Metal Version:1.28.0-gke.435Anthos Bare Metal Versions:1.28.0-gke.435:3Conditions:. . .Last Transition Time:2023-11-15T18:32:25ZObserved Generation:1Reason:ReconciliationCompletedStatus:FalseType:Reconciling
在執行中的叢集更新 API 伺服器憑證的額外 SAN 欄位時，可能會發生停機情形：
在高可用性 (HA) 叢集上，API 伺服器執行個體會依序重新啟動。由於負載平衡器會將要求分配給每個 API 伺服器，因此您在更新憑證期間仍可與叢集互動。不過，您可能會看到 API 伺服器即將關閉的回應。如果看到這項回應，請重試要求。
在非高可用性叢集上，API 伺服器重新啟動以重新載入新憑證時，可能會短暫中斷約一分鐘。
視叢集中的控制層節點數量和叢集負載而定，這項變更需要 5 到 20 分鐘才能傳播至所有 API 伺服器。
[[["容易理解","easyToUnderstand","thumb-up"],["確實解決了我的問題","solvedMyProblem","thumb-up"],["其他","otherUp","thumb-up"]],[["難以理解","hardToUnderstand","thumb-down"],["資訊或程式碼範例有誤","incorrectInformationOrSampleCode","thumb-down"],["缺少我需要的資訊/範例","missingTheInformationSamplesINeed","thumb-down"],["翻譯問題","translationIssue","thumb-down"],["其他","otherDown","thumb-down"]],["上次更新時間：2025-09-01 (世界標準時間)。"],[],[],null,["A subject alternative name (SAN) is a feature of SSL certificates that lets you\ndefine the domain names and subdomains that are secured by a certificate. On an\nGoogle Distributed Cloud cluster, the default SANs for the Kubernetes API server\ncertificate include the IP and VIP addresses of the control plane nodes and the\nKubernetes DNS names. With the custom API server certificate extra SANs feature,\nyou can add additional domains, subdomains, and IP addresses as SANs to the\nKubernetes API server certificate for the cluster.\n\nTo specify custom SANs for the API server certificate, you use the\n[`controlPlane.apiServerCertExtraSANs`](/kubernetes-engine/distributed-cloud/bare-metal/docs/reference/cluster-config-ref#controlplane-apiservercertextrasans)\nfield in the cluster configuration spec. This field takes a list of domain names\nand IP addresses. This field is optional and mutable. You can add this field and\nupdate it when you create a cluster or any time after. \n\n ...\n kind: Cluster\n metadata:\n name: sample001\n namespace: cluster-sample001\n spec:\n type: user\n ...\n controlPlane:apiServerCertExtraSANs:\n - \"demo-dns.example.com\"\n - \"sample-dns.com\"\n nodePoolSpec:\n nodes:\n - address: 10.200.0.20\n clusterNetwork:\n ...\n\nAdd domains during cluster creation\n\nWhen you add extra SANs when you create a cluster, the Kubernetes API server\ncertificate includes the additional specified domains and IP addresses when the\ncluster becomes available.\n\nAdd or update domains for an existing cluster\n\nBecause the `apiServerCertExtraSANs` field is mutable, you can add or update the\nfield at any time for existing clusters. When you modify the\n`apiServerCertExtraSANs` field in the cluster, it triggers the following\nactivities:\n\n- The Google Distributed Cloud cluster controllers regenerate the API server\n certificate to include the modified extra domains.\n\n- The cluster controllers restart the API server to reload the new\n certificate.\n\n- The new values of `apiServerCertExtraSANs` are verified by a webhook to\n ensure that they conform to the [RFC 1035 domain name\n conventions](https://datatracker.ietf.org/doc/html/rfc1035).\n\n- The control plane node pool enters a reconciling state.\n\n Control Plane Node Pool Status:\n Anthos Bare Metal Version: 1.28.0-gke.435\n Anthos Bare Metal Versions:\n 1.28.0-gke.435: 3\n Conditions:\n ...\n Last Transition Time: 2023-11-15T18:23:49Z\n Observed Generation: 1Reason: Reconciling\n Status: True\n Type: Reconciling\n\n- The node pool becomes ready after the change propagates to the Kubernetes\n API servers on each control plane node.\n\n Control Plane Node Pool Status:\n Anthos Bare Metal Version: 1.28.0-gke.435\n Anthos Bare Metal Versions:\n 1.28.0-gke.435: 3\n Conditions:\n . . .\n Last Transition Time: 2023-11-15T18:32:25Z\n Observed Generation: 1Reason: ReconciliationCompleted\n Status: False\n Type: Reconciling\n\nYou might experience downtime when updating the API server certificate extra\nSANs field on a running cluster:\n\n- On high availability (HA) clusters, API server instances restart\n sequentially. You can still interact with the cluster during the certificate\n update, because the load balancer distributes requests to each API server.\n However, you might see a response indicating that the API server is shutting\n down. If you see this response, retry the request.\n\n- On non-HA clusters, there might be a brief outage of about one minute while\n an API server restarts to reload the new certificate.\n\nThe change takes 5-20 minutes to propagate to all API servers, depending on the\nnumber of control plane nodes in the cluster and the load of the cluster."]]
