Kubernetes cadvisor 端点未被普罗米修斯抓取

Question

我安装了一个 minikube kubernetes 集群，它通过 prometheus 进行监控。 kubernetes 版本是 v1.13.4，直接在 vm 主机上运行（--vm-driver=none）。我在 Prometheus 配置文件中添加了一个特定的作业，以便抓取 cadvisor 容器指标。问题是 Prometheus 无法从 cadvisor 端点抓取指标。

我在 prometheus.yml 中包含以下配置

- job_name: 'kubernetes-cadvisor'
  kubernetes_sd_configs:
  - role: node
  relabel_configs:
  - action: labelmap
    regex: __meta_kubernetes_node_label_(.+)
  - target_label: __address__
    replacement:  kubernetes.default.svc:443
  - source_labels: [__meta_kubernetes_node_name]
    regex: (.+)
    target_label: __metrics_path__
    replacement: /api/v1/nodes/${1}/proxy/metrics/cadvisor

但在 prometheus 目标 web UI (http://my_ip:30900/targets) 我看到“kubernetes-cadvisor”处于 DOWN 状态并显示以下错误消息

http://kubernetes.default.svc:443/api/v1/nodes/minikube/proxy/metrics/cadvisor: context deadline exceeded

kubernetes.default.svc:443 应该是默认集群 DNS，可以从 pod 中访问，但正如预期的那样，我无法在 prometheus pod 中 ping 它。

幸运的是，我注意到我可以从 url 成功获取所有 cadvisor 容器指标：

http://my_dashboard_ip_and_port/api/v1/nodes/minikube/proxy/metrics/cadvisor

prometheus pod 中的日志是：

kubectl logs prometheus-deployment-6f64ff68f9-8c9xm
level=info ts=2019-03-29T14:33:18.939973334Z caller=main.go:285 msg="no time or size retention was set so using the default time retention" duration=15d
level=info ts=2019-03-29T14:33:18.940326462Z caller=main.go:321 msg="Starting Prometheus" version="(version=2.8.1, branch=HEAD, revision=4d60eb36dcbed725fcac5b27018574118f12fffb)"
level=info ts=2019-03-29T14:33:18.94039376Z caller=main.go:322 build_context="(go=go1.11.6, user=root@bfdd6a22a683, date=20190328-18:04:08)"
level=info ts=2019-03-29T14:33:18.940455316Z caller=main.go:323 host_details="(Linux 4.15.0 #1 SMP Tue Mar 26 02:53:14 UTC 2019 x86_64 prometheus-deployment-6f64ff68f9-8c9xm (none))"
level=info ts=2019-03-29T14:33:18.94050961Z caller=main.go:324 fd_limits="(soft=1048576, hard=1048576)"
level=info ts=2019-03-29T14:33:18.940570849Z caller=main.go:325 vm_limits="(soft=unlimited, hard=unlimited)"
level=info ts=2019-03-29T14:33:18.941555805Z caller=main.go:640 msg="Starting TSDB ..."
level=info ts=2019-03-29T14:33:18.941946171Z caller=web.go:418 component=web msg="Start listening for connections" address=0.0.0.0:9090
level=info ts=2019-03-29T14:33:18.946861683Z caller=main.go:655 msg="TSDB started"
level=info ts=2019-03-29T14:33:18.947193152Z caller=main.go:724 msg="Loading configuration file" filename=/etc/prometheus/prometheus.yml
level=info ts=2019-03-29T14:33:18.948922627Z caller=kubernetes.go:191 component="discovery manager scrape" discovery=k8s msg="Using pod service account via in-cluster config"
level=info ts=2019-03-29T14:33:18.950164896Z caller=kubernetes.go:191 component="discovery manager scrape" discovery=k8s msg="Using pod service account via in-cluster config"
level=info ts=2019-03-29T14:33:18.951281382Z caller=kubernetes.go:191 component="discovery manager scrape" discovery=k8s msg="Using pod service account via in-cluster config"
level=info ts=2019-03-29T14:33:18.952276845Z caller=main.go:751 msg="Completed loading of configuration file" filename=/etc/prometheus/prometheus.yml
level=info ts=2019-03-29T14:33:18.952303937Z caller=main.go:609 msg="Server is ready to receive web requests."

但我不知道如何正确配置 Prometheus yml 文件，以便也能够通过 Prometheus 获取公开的指标。

非常感谢。

Answer 1

我想您可能必须使用 HTTPS 架构来针对 HTTP 抓取请求，这似乎保留在您的配置中：

- job_name: 'kubernetes-cadvisor'

  scheme: https

  tls_config:
    ca_file: /var/run/secrets/kubernetes.io/serviceaccount/ca.crt
  bearer_token_file: /var/run/secrets/kubernetes.io/serviceaccount/token

  kubernetes_sd_configs:
  - role: node

  relabel_configs:
  - action: labelmap
    regex: __meta_kubernetes_node_label_(.+)
  - target_label: __address__
    replacement: kubernetes.default.svc:443
  - source_labels: [__meta_kubernetes_node_name]
    regex: (.+)
    target_label: __metrics_path__
    replacement: /api/v1/nodes/${1}/proxy/metrics/cadvisor

为了跳过 API 服务器证书验证，您可以将 insecure_skip_verify: true 参数添加到现有的 tls_config：

tls_config:
  ca_file: /var/run/secrets/kubernetes.io/serviceaccount/ca.crt
  insecure_skip_verify: true