# 错误：无法获取CPU利用率：无法获取资源CPU的指标：无法从资源指标API获取指标

- **ID:** `kubernetes/hpa-missing-metrics-server`
- **领域:** kubernetes
- **类别:** resource_error
- **验证级别:** ai_generated
- **修复率:** 85%

## 根因

水平Pod自动缩放器（HPA）无法查询CPU/指标，因为metrics-server未部署或运行不正常。

## 版本兼容性

| 版本 | 状态 | 引入 | 弃用 |
|------|------|------|------|
| metrics-server v0.6.4 | active | — | — |
| Kubernetes v1.28.3 | active | — | — |
| Kubernetes v1.29.0 | active | — | — |

## 解决方案

1. ```
   Deploy metrics-server using the official manifest: `kubectl apply -f https://github.com/kubernetes-sigs/metrics-server/releases/latest/download/components.yaml`
   ```
2. ```
   Check metrics-server pod logs: `kubectl logs -n kube-system deployment/metrics-server` and verify it can connect to kubelets. Common fix: add --kubelet-insecure-tls flag if using self-signed certs.
   ```

## 无效尝试

- **Install a custom Prometheus adapter instead of metrics-server** — HPA requires the resource metrics API, which is typically served by metrics-server. Prometheus adapter serves custom metrics, not resource metrics. (70% 失败率)
- **Set --horizontal-pod-autoscaler-use-rest-clients=false on kube-controller-manager** — This flag is deprecated and removed in recent Kubernetes versions (1.23+). It no longer affects HPA behavior. (90% 失败率)