このページでは、Google Distributed Cloud の Kubernetes API サーバー（kube-apiserver）の問題を解決する方法について説明します。
このページは、基盤となるテクノロジー インフラストラクチャのライフサイクルを管理し、サービスレベル目標（SLO）が達成されていない場合やアプリケーションで障害が発生した場合にアラートやページに対応する IT 管理者とオペレーターを対象としています。 Google Cloudのコンテンツで使用されている一般的なロールとタスクの例の詳細については、一般的な GKE Enterprise ユーザーロールとタスクをご覧ください。
# Replace "--ca-cert /path/to/ca.pem" to "--insecure" if you are accessing# a local cluster and you trust the connection cannot be tampered.# The output is always "ok" and thus contains no sensentive information.
curl-v--cacert/path/to/ca.pemhttps://192.0.2.1:36917/healthz
このコマンドの出力は通常、失敗した接続の根本原因を示します。
接続に成功しても、速度が遅かったりタイムアウトになった場合は、API サーバーの負荷が過剰であることを示します。コンソールで確認するには、API
Server Request Rate を確認して、Cloud Kubernetes > Anthos >
Cluster > K8s Control Plane にレイテンシ指標をリクエストします。
[[["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 2025-07-31 UTC。"],[],[],null,["This page shows you how to resolve issues with the Kubernetes API server\n(`kube-apiserver`) for Google Distributed Cloud.\n\nThis page is for IT administrators and Operators who manage the\nlifecycle of the underlying tech infrastructure, and respond to alerts and pages\nwhen service level objectives (SLOs) aren't met or applications fail. To learn\nmore about common roles and example tasks that we reference in Google Cloud\ncontent, see\n[Common GKE user roles and tasks](/kubernetes-engine/enterprise/docs/concepts/roles-tasks).\n\nWebhook timeouts and failed webhook calls\n\nThese errors might be seen in a few different ways. If you experience any of the\nfollowing symptoms, it's possible that webhook calls are failing:\n\n- **Connection refused:** If `kube-apiserver` reports timeout errors for\n calling the webhook, the following error is reported in the logs:\n\n failed calling webhook \"server.system.private.gdc.goog\":\n failed to call webhook: Post \"https://root-admin-webhook.gpc-system.svc:443/mutate-system-private-gdc-goog-v1alpha1-server?timeout=10s\":\n dial tcp 10.202.1.18:443: connect: connection refused\n\n- **Context deadline exceeded:** You might also see the following error reported\n in the logs:\n\n failed calling webhook \"namespaces.hnc.x-k8s.io\": failed to call webhook: Post\n \"https://hnc-webhook-service.hnc-system.svc:443/validate-v1-namespace?timeout=10s\\\":\n context deadline exceeded\"\n\nIf you think that you are experiencing webhook timeouts or failed webhook calls,\nuse one of the following methods to confirm the issue:\n\n- Check the API server log to see if there is network issue.\n\n - Check the log for network-related errors like `TLS handshake error`.\n - Check if the IP/Port matches what the API server is configured to respond on.\n- Monitor webhook latency with the following steps:\n\n 1. In the console, go to the Cloud Monitoring page.\n\n [Go to the Cloud Monitoring page](https://console.cloud.google.com/monitoring/)\n 2. Select **Metrics explorer**.\n\n 3. Select the `apiserver_admission_webhook_admission_duration_seconds` metric.\n\nTo resolve this issue, review the following suggestions:\n\n- Additional firewall rules might be required for the webhook. For more\n information, see how to\n [add firewall rules for specific use cases](/kubernetes-engine/docs/how-to/private-clusters#add_firewall_rules).\n\n- If the webhook requires more time to complete, you can\n [configure a custom timeout value](https://kubernetes.io/docs/reference/access-authn-authz/extensible-admission-controllers/#timeouts).\n The webhooks latency adds to API request latency, so should be evaluated as\n quickly as possible.\n\n- If the webhook error blocks cluster availability or the webhook is harmless\n to remove and mitigates the situation, check if it's possible to temporarily\n set the `failurePolicy` to `Ignore` or remove the offending webhook.\n\nAPI server dial failure or latency\n\nThis error might be seen in a few different ways:\n\n- **External name resolution errors:** An external client might return errors\n that contain `lookup` in the message, such as:\n\n dial tcp: lookup kubernetes.example.com on 127.0.0.1:53: no such host\n\n This error doesn't apply to a client running within the cluster. The\n Kubernetes Service IP is injected, so no resolution is required.\n- **Network errors:** The client might print a generic network error when trying\n to dial the API server, like the following examples:\n\n dial tcp 10.96.0.1:443: connect: no route to host\n dial tcp 10.96.0.1:443: connect: connection refused\n dial tcp 10.96.0.1:443: connect: i/o timeout\n\n- **High latency connecting to API server:** The connection to API server might\n be successful, but the requests timeout on the client side. In this scenario,\n the client usually prints error messages containing `context deadline\n exceeded`.\n\nIf the connection to the API server fails completely, try the connection within\nthe same environment where the client reports the error.\n[Kubernetes ephemeral containers](https://kubernetes.io/docs/concepts/workloads/pods/ephemeral-containers/)\ncan be used to inject a debugging container to the existing namespaces as\nfollows:\n\n1. From where the problematic client runs, use `kubectl` to perform a request\n with high verbosity. For example, a `GET` request to `/healthz` usually\n requires no authentication:\n\n kubectl get -v999 --raw /healthz\n\n2. If the request fails or `kubectl` is unavailable, you can obtain the URL from\n the output and manually perform the request with `curl`. For example, if the\n service host obtained from the previous output was `https://192.0.2.1:36917/`,\n you can send a similar request as follows:\n\n # Replace \"--ca-cert /path/to/ca.pem\" to \"--insecure\" if you are accessing\n # a local cluster and you trust the connection cannot be tampered.\n # The output is always \"ok\" and thus contains no sensentive information.\n\n curl -v --cacert /path/to/ca.pem https://192.0.2.1:36917/healthz\n\n The output from this command usually indicates the root cause of a failed\n connection.\n | **Note:** You can't use the `ping` or `traceroute` commands to the IP address. A Kubernetes Service IP doesn't accept ICMP or protocols outside the list defined in the Service resource.\n\n If the connection is successful but is slow or times out, it indicates an\n overloaded API server. To confirm, in the console look at `API\n Server Request Rate` and request latency metrics in `Cloud Kubernetes \u003e Anthos \u003e\n Cluster \u003e K8s Control Plane`.\n\nTo resolve these connection failures or latency problems, review the following\nremediation options:\n\n- If a network error occurs within the cluster, there might be problem with the\n Container Network Interface (CNI) plugin. This problem is usually transient\n and resolves itself after a Pod recreation or reschedule.\n\n- If the network error is from outside the cluster, check if the client is\n properly configured to access the cluster, or generate the client\n configuration again. If the connection goes through a proxy or gateway, check\n if another connection that goes through the same mechanism works.\n\n- If the API server is overloaded, it usually means that many clients access the\n API server at the same time. A single client can't overload an API server due\n to throttling and the\n [Priority and Fairness](https://kubernetes.io/docs/concepts/cluster-administration/flow-control/)\n feature. Review the workload for the following areas:\n\n - Works at Pod level. It's more common to mistakenly create and forget Pods than higher level resources.\n - Adjust the number of replicas through erroneous calculation.\n - A webhook that loops back the request to itself or amplifies the load by creating more requests than it handles.\n\nWhat's next\n\nIf you need additional assistance, reach out to\n\n[Cloud Customer Care](/support-hub).\n\nYou can also see\n[Getting support](/kubernetes-engine/distributed-cloud/vmware/docs/getting-support) for more information about support resources, including the following:\n\n- [Requirements](/kubernetes-engine/distributed-cloud/vmware/docs/getting-support#support_requirements) for opening a support case.\n- [Tools](/kubernetes-engine/distributed-cloud/vmware/docs/getting-support#support_tools) to help you troubleshoot, such as logs and metrics.\n- Supported [components](/kubernetes-engine/distributed-cloud/vmware/docs/getting-support#whats_supported), [versions](/kubernetes-engine/distributed-cloud/vmware/docs/getting-support#version_support_policy), and [features](/kubernetes-engine/distributed-cloud/vmware/docs/getting-support#supported_features) of Google Distributed Cloud for VMware (software only)."]]
