主体备用名称 (SAN) 是 SSL 证书的一项功能，可让您定义由证书提供安全保护的域名和子网域。在 Google Distributed Cloud 集群上，Kubernetes API 服务器证书的默认 SAN 包含控制平面节点的 IP 和 VIP 地址以及 Kubernetes DNS 名称。借助自定义 API 服务器证书额外 SAN 功能，您可以将其他网域、子网域和 IP 地址作为 SAN 添加到集群的 Kubernetes API 服务器证书。
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
更改传播到每个控制平面节点上的 Kubernetes API 服务器后，节点池就会变为就绪状态。
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
在运行中的集群上更新 API 服务器证书额外 SAN 字段时，您可能会遇到停机：
在高可用性 (HA) 集群中，API 服务器实例会依序重启。在证书更新期间，您仍然可以与集群进行交互，因为负载均衡器会将请求分发到每个 API 服务器。不过，您可能会看到响应，指明 API 服务器正在关闭。如果您看到此响应，请重试请求。
在非 HA 集群中，在 API 服务器重启以重新加载新证书时，可能会出现大约一分钟的短暂服务中断。
更改需要 5-20 分钟才能传播到所有 API 服务器，具体取决于集群中的控制平面节点数和集群的负载。
[[["易于理解","easyToUnderstand","thumb-up"],["解决了我的问题","solvedMyProblem","thumb-up"],["其他","otherUp","thumb-up"]],[["很难理解","hardToUnderstand","thumb-down"],["信息或示例代码不正确","incorrectInformationOrSampleCode","thumb-down"],["没有我需要的信息/示例","missingTheInformationSamplesINeed","thumb-down"],["翻译问题","translationIssue","thumb-down"],["其他","otherDown","thumb-down"]],["最后更新时间 (UTC)：2025-09-01。"],[],[],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."]]
