k8s與監控--解讀prometheus監控kubernetes的配置文件

時間  2019-11-06
標籤 k8s 監控 解讀 prometheus kubernetes 配置文件 简体版
原文   原文鏈接

前言

Prometheus 是一個開源和社區驅動的監控&報警&時序數據庫的項目。來源於谷歌BorgMon項目。如今最多見的Kubernetes容器管理系統中，一般會搭配Prometheus進行監控。主要監控：node

  • Node:如主機CPU，內存，網絡吞吐和帶寬佔用，磁盤I/O和磁盤使用等指標。node-exporter採集。
  • 容器關鍵指標:集羣中容器的CPU詳細情況，內存詳細情況，Network，FileSystem和Subcontainer等。經過cadvisor採集。
  • Kubernetes集羣上部署的應用：監控部署在Kubernetes集羣上的應用。主要是pod，service，ingress和endpoint。經過black-box和kube-apiserver的接口採集。

prometheus自身提供了一些資源的自動發現功能，下面是我從官方github上截圖，羅列了目前提供的資源發現：
圖片描述
由上圖可知prometheus自身提供了自動發現kubernetes的監控目標的功能。相應，配置文件官方也提供了一份，今天咱們就解讀一下該配置文件。git

配置文件解讀

首先直接上官方的配置文件：github

# A scrape configuration for running Prometheus on a Kubernetes cluster.
# This uses separate scrape configs for cluster components (i.e. API server, node)
# and services to allow each to use different authentication configs.
#
# Kubernetes labels will be added as Prometheus labels on metrics via the
# `labelmap` relabeling action.
#
# If you are using Kubernetes 1.7.2 or earlier, please take note of the comments
# for the kubernetes-cadvisor job; you will need to edit or remove this job.

# Scrape config for API servers.
#
# Kubernetes exposes API servers as endpoints to the default/kubernetes
# service so this uses `endpoints` role and uses relabelling to only keep
# the endpoints associated with the default/kubernetes service using the
# default named port `https`. This works for single API server deployments as
# well as HA API server deployments.
scrape_configs:
- job_name: 'kubernetes-apiservers'

  kubernetes_sd_configs:
  - role: endpoints

  # Default to scraping over https. If required, just disable this or change to
  # `http`.
  scheme: https

  # This TLS & bearer token file config is used to connect to the actual scrape
  # endpoints for cluster components. This is separate to discovery auth
  # configuration because discovery & scraping are two separate concerns in
  # Prometheus. The discovery auth config is automatic if Prometheus runs inside
  # the cluster. Otherwise, more config options have to be provided within the
  # <kubernetes_sd_config>.
  tls_config:
    ca_file: /var/run/secrets/kubernetes.io/serviceaccount/ca.crt
    # If your node certificates are self-signed or use a different CA to the
    # master CA, then disable certificate verification below. Note that
    # certificate verification is an integral part of a secure infrastructure
    # so this should only be disabled in a controlled environment. You can
    # disable certificate verification by uncommenting the line below.
    #
    # insecure_skip_verify: true
  bearer_token_file: /var/run/secrets/kubernetes.io/serviceaccount/token

  # Keep only the default/kubernetes service endpoints for the https port. This
  # will add targets for each API server which Kubernetes adds an endpoint to
  # the default/kubernetes service.
  relabel_configs:
  - source_labels: [__meta_kubernetes_namespace, __meta_kubernetes_service_name, __meta_kubernetes_endpoint_port_name]
    action: keep
    regex: default;kubernetes;https

# Scrape config for nodes (kubelet).
#
# Rather than connecting directly to the node, the scrape is proxied though the
# Kubernetes apiserver.  This means it will work if Prometheus is running out of
# cluster, or can't connect to nodes for some other reason (e.g. because of
# firewalling).
- job_name: 'kubernetes-nodes'

  # Default to scraping over https. If required, just disable this or change to
  # `http`.
  scheme: https

  # This TLS & bearer token file config is used to connect to the actual scrape
  # endpoints for cluster components. This is separate to discovery auth
  # configuration because discovery & scraping are two separate concerns in
  # Prometheus. The discovery auth config is automatic if Prometheus runs inside
  # the cluster. Otherwise, more config options have to be provided within the
  # <kubernetes_sd_config>.
  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

# Scrape config for Kubelet cAdvisor.
#
# This is required for Kubernetes 1.7.3 and later, where cAdvisor metrics
# (those whose names begin with 'container_') have been removed from the
# Kubelet metrics endpoint.  This job scrapes the cAdvisor endpoint to
# retrieve those metrics.
#
# In Kubernetes 1.7.0-1.7.2, these metrics are only exposed on the cAdvisor
# HTTP endpoint; use "replacement: /api/v1/nodes/${1}:4194/proxy/metrics"
# in that case (and ensure cAdvisor's HTTP server hasn't been disabled with
# the --cadvisor-port=0 Kubelet flag).
#
# This job is not necessary and should be removed in Kubernetes 1.6 and
# earlier versions, or it will cause the metrics to be scraped twice.
- job_name: 'kubernetes-cadvisor'

  # Default to scraping over https. If required, just disable this or change to
  # `http`.
  scheme: https

  # This TLS & bearer token file config is used to connect to the actual scrape
  # endpoints for cluster components. This is separate to discovery auth
  # configuration because discovery & scraping are two separate concerns in
  # Prometheus. The discovery auth config is automatic if Prometheus runs inside
  # the cluster. Otherwise, more config options have to be provided within the
  # <kubernetes_sd_config>.
  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

# Scrape config for service endpoints.
#
# The relabeling allows the actual service scrape endpoint to be configured
# via the following annotations:
#
# * `prometheus.io/scrape`: Only scrape services that have a value of `true`
# * `prometheus.io/scheme`: If the metrics endpoint is secured then you will need
# to set this to `https` & most likely set the `tls_config` of the scrape config.
# * `prometheus.io/path`: If the metrics path is not `/metrics` override this.
# * `prometheus.io/port`: If the metrics are exposed on a different port to the
# service then set this appropriately.
- job_name: 'kubernetes-service-endpoints'

  kubernetes_sd_configs:
  - role: endpoints

  relabel_configs:
  - source_labels: [__meta_kubernetes_service_annotation_prometheus_io_scrape]
    action: keep
    regex: true
  - source_labels: [__meta_kubernetes_service_annotation_prometheus_io_scheme]
    action: replace
    target_label: __scheme__
    regex: (https?)
  - source_labels: [__meta_kubernetes_service_annotation_prometheus_io_path]
    action: replace
    target_label: __metrics_path__
    regex: (.+)
  - source_labels: [__address__, __meta_kubernetes_service_annotation_prometheus_io_port]
    action: replace
    target_label: __address__
    regex: ([^:]+)(?::\d+)?;(\d+)
    replacement: $1:$2
  - action: labelmap
    regex: __meta_kubernetes_service_label_(.+)
  - source_labels: [__meta_kubernetes_namespace]
    action: replace
    target_label: kubernetes_namespace
  - source_labels: [__meta_kubernetes_service_name]
    action: replace
    target_label: kubernetes_name

# Example scrape config for probing services via the Blackbox Exporter.
#
# The relabeling allows the actual service scrape endpoint to be configured
# via the following annotations:
#
# * `prometheus.io/probe`: Only probe services that have a value of `true`
- job_name: 'kubernetes-services'

  metrics_path: /probe
  params:
    module: [http_2xx]

  kubernetes_sd_configs:
  - role: service

  relabel_configs:
  - source_labels: [__meta_kubernetes_service_annotation_prometheus_io_probe]
    action: keep
    regex: true
  - source_labels: [__address__]
    target_label: __param_target
  - target_label: __address__
    replacement: blackbox-exporter.example.com:9115
  - source_labels: [__param_target]
    target_label: instance
  - action: labelmap
    regex: __meta_kubernetes_service_label_(.+)
  - source_labels: [__meta_kubernetes_namespace]
    target_label: kubernetes_namespace
  - source_labels: [__meta_kubernetes_service_name]
    target_label: kubernetes_name

# Example scrape config for probing ingresses via the Blackbox Exporter.
#
# The relabeling allows the actual ingress scrape endpoint to be configured
# via the following annotations:
#
# * `prometheus.io/probe`: Only probe services that have a value of `true`
- job_name: 'kubernetes-ingresses'

  metrics_path: /probe
  params:
    module: [http_2xx]

  kubernetes_sd_configs:
    - role: ingress

  relabel_configs:
    - source_labels: [__meta_kubernetes_ingress_annotation_prometheus_io_probe]
      action: keep
      regex: true
    - source_labels: [__meta_kubernetes_ingress_scheme,__address__,__meta_kubernetes_ingress_path]
      regex: (.+);(.+);(.+)
      replacement: ${1}://${2}${3}
      target_label: __param_target
    - target_label: __address__
      replacement: blackbox-exporter.example.com:9115
    - source_labels: [__param_target]
      target_label: instance
    - action: labelmap
      regex: __meta_kubernetes_ingress_label_(.+)
    - source_labels: [__meta_kubernetes_namespace]
      target_label: kubernetes_namespace
    - source_labels: [__meta_kubernetes_ingress_name]
      target_label: kubernetes_name

# Example scrape config for pods
#
# The relabeling allows the actual pod scrape endpoint to be configured via the
# following annotations:
#
# * `prometheus.io/scrape`: Only scrape pods that have a value of `true`
# * `prometheus.io/path`: If the metrics path is not `/metrics` override this.
# * `prometheus.io/port`: Scrape the pod on the indicated port instead of the
# pod's declared ports (default is a port-free target if none are declared).
- job_name: 'kubernetes-pods'

  kubernetes_sd_configs:
  - role: pod

  relabel_configs:
  - source_labels: [__meta_kubernetes_pod_annotation_prometheus_io_scrape]
    action: keep
    regex: true
  - source_labels: [__meta_kubernetes_pod_annotation_prometheus_io_path]
    action: replace
    target_label: __metrics_path__
    regex: (.+)
  - source_labels: [__address__, __meta_kubernetes_pod_annotation_prometheus_io_port]
    action: replace
    regex: ([^:]+)(?::\d+)?;(\d+)
    replacement: $1:$2
    target_label: __address__
  - action: labelmap
    regex: __meta_kubernetes_pod_label_(.+)
  - source_labels: [__meta_kubernetes_namespace]
    action: replace
    target_label: kubernetes_namespace
  - source_labels: [__meta_kubernetes_pod_name]
    action: replace
    target_label: kubernetes_pod_name

固然該配置文件，是在prometheus部署在k8s中生效的,即in-cluster模式。數據庫

kubernetes-apiservers

該項主要是讓prometheus程序能夠訪問kube-apiserver，進而進行服務發現。看一下服務發現的代碼能夠看出，主要服務發現：node，service，ingress，pod。api

switch d.role {
    case "endpoints":
        var wg sync.WaitGroup

        for _, namespace := range namespaces {
            elw := cache.NewListWatchFromClient(rclient, "endpoints", namespace, nil)
            slw := cache.NewListWatchFromClient(rclient, "services", namespace, nil)
            plw := cache.NewListWatchFromClient(rclient, "pods", namespace, nil)
            eps := NewEndpoints(
                log.With(d.logger, "role", "endpoint"),
                cache.NewSharedInformer(slw, &apiv1.Service{}, resyncPeriod),
                cache.NewSharedInformer(elw, &apiv1.Endpoints{}, resyncPeriod),
                cache.NewSharedInformer(plw, &apiv1.Pod{}, resyncPeriod),
            )
            go eps.endpointsInf.Run(ctx.Done())
            go eps.serviceInf.Run(ctx.Done())
            go eps.podInf.Run(ctx.Done())

            for !eps.serviceInf.HasSynced() {
                time.Sleep(100 * time.Millisecond)
            }
            for !eps.endpointsInf.HasSynced() {
                time.Sleep(100 * time.Millisecond)
            }
            for !eps.podInf.HasSynced() {
                time.Sleep(100 * time.Millisecond)
            }
            wg.Add(1)
            go func() {
                defer wg.Done()
                eps.Run(ctx, ch)
            }()
        }
        wg.Wait()
    case "pod":
        var wg sync.WaitGroup
        for _, namespace := range namespaces {
            plw := cache.NewListWatchFromClient(rclient, "pods", namespace, nil)
            pod := NewPod(
                log.With(d.logger, "role", "pod"),
                cache.NewSharedInformer(plw, &apiv1.Pod{}, resyncPeriod),
            )
            go pod.informer.Run(ctx.Done())

            for !pod.informer.HasSynced() {
                time.Sleep(100 * time.Millisecond)
            }
            wg.Add(1)
            go func() {
                defer wg.Done()
                pod.Run(ctx, ch)
            }()
        }
        wg.Wait()
    case "service":
        var wg sync.WaitGroup
        for _, namespace := range namespaces {
            slw := cache.NewListWatchFromClient(rclient, "services", namespace, nil)
            svc := NewService(
                log.With(d.logger, "role", "service"),
                cache.NewSharedInformer(slw, &apiv1.Service{}, resyncPeriod),
            )
            go svc.informer.Run(ctx.Done())

            for !svc.informer.HasSynced() {
                time.Sleep(100 * time.Millisecond)
            }
            wg.Add(1)
            go func() {
                defer wg.Done()
                svc.Run(ctx, ch)
            }()
        }
        wg.Wait()
    case "ingress":
        var wg sync.WaitGroup
        for _, namespace := range namespaces {
            ilw := cache.NewListWatchFromClient(reclient, "ingresses", namespace, nil)
            ingress := NewIngress(
                log.With(d.logger, "role", "ingress"),
                cache.NewSharedInformer(ilw, &extensionsv1beta1.Ingress{}, resyncPeriod),
            )
            go ingress.informer.Run(ctx.Done())

            for !ingress.informer.HasSynced() {
                time.Sleep(100 * time.Millisecond)
            }
            wg.Add(1)
            go func() {
                defer wg.Done()
                ingress.Run(ctx, ch)
            }()
        }
        wg.Wait()
    case "node":
        nlw := cache.NewListWatchFromClient(rclient, "nodes", api.NamespaceAll, nil)
        node := NewNode(
            log.With(d.logger, "role", "node"),
            cache.NewSharedInformer(nlw, &apiv1.Node{}, resyncPeriod),
        )
        go node.informer.Run(ctx.Done())

        for !node.informer.HasSynced() {
            time.Sleep(100 * time.Millisecond)
        }
        node.Run(ctx, ch)

    default:
        level.Error(d.logger).Log("msg", "unknown Kubernetes discovery kind", "role", d.role)
    }

kubernetes-nodes

發現node之後，經過/api/v1/nodes/${1}/proxy/metrics來獲取node的metrics。安全

kubernetes-cadvisor

cadvisor已經被集成在kubelet中，因此發現了node就至關於發現了cadvisor。經過 /api/v1/nodes/${1}/proxy/metrics/cadvisor採集容器指標。網絡

kubernetes-services和kubernetes-ingresses

該兩種資源監控方式差很少，都是須要安裝black-box，而後相似於探針去定時訪問，根據返回的http狀態碼來斷定service和ingress的服務可用性。
PS：不過我本身在這裏和官方的稍微有點區別，app

- target_label: __address__
      replacement: blackbox-exporter.example.com:9115

官方大體是須要咱們要建立black-box 的ingress從外部訪問，這樣從效率和安全性都不是最合適的。因此我通常都是直接內部dns訪問。以下ide

- target_label: __address__
      replacement: blackbox-exporter.kube-system:9115

固然看源碼能夠發現，並非全部的service和ingress都會健康監測，若是須要將服務進行健康監測，那麼你部署應用的yaml文件加一些註解。例如：
對於service和ingress：
須要加註解：prometheus.io/scrape: 'true'ui

apiVersion: v1
kind: Service
metadata:
  annotations:
    prometheus.io/scrape: 'true'
  name: prometheus-node-exporter
  namespace: kube-system
  labels:
    app: prometheus
    component: node-exporter
spec:
  clusterIP: None
  ports:
    - name: prometheus-node-exporter
      port: 9100
      protocol: TCP
  selector:
    app: prometheus
    component: node-exporter
  type: ClusterIP

kubernetes-pods

對於pod的監測也是須要加註解：

  • prometheus.io/scrape，爲true則會將pod做爲監控目標。
  • prometheus.io/path，默認爲/metrics
  • prometheus.io/port , 端口

因此看到此處能夠看出，該job並非監控pod的指標，pod已經經過前面的cadvisor採集。此處是對pod中應用的監控。寫過exporter的人應該對這個概念很是清楚。通俗講，就是你pod中的應用提供了prometheus的監控功能，加上對應的註解，那麼該應用的metrics會定時被採集走。

kubernetes-service-endpoints

對於服務的終端節點，也須要加註解：

  • prometheus.io/scrape，爲true則會將pod做爲監控目標。
  • prometheus.io/path，默認爲/metrics
  • prometheus.io/port , 端口
  • prometheus.io/scheme 默認http，若是爲了安全設置了https，此處須要改成https

這個基本上同上的。採集service-endpoints的metrics。

我的認爲：若是某些部署應用只有pod沒有service，那麼這種狀況只能在pod上加註解，經過kubernetes-pods採集metrics。若是有service，那麼就無需在pod加註解了，直接在service上加便可。畢竟service-endpoints最終也會落到pod上。

總結

配置項總結

  • kubernetes-service-endpoints和kubernetes-pods採集應用中metrics，固然並非全部的都提供了metrics接口。
  • kubernetes-ingresses 和kubernetes-services 健康監測服務和ingress健康的狀態
  • kubernetes-cadvisor 和 kubernetes-nodes，經過發現node，監控node 和容器的cpu等指標

自動發現源碼

參考client-go和prometheus自動發現k8s，這種監聽k8s集羣中資源的變化，使用informer實現，不要輪詢kube-apiserver接口。

參考

該配置文件須要部署一些組件來支持prometheus對k8s的監控，例如black-exporter。由於要自動發現，獲取集羣的一些信息，因此也要作rbac的受權。具體參考：
github

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