Prometheus在K8S中的应用和配置

一、在K8S平台部署Prometheus

IP	角色
192.168.73.136	nfs
192.168.73.138	k8s-master
192.168.73.139	k8s-node1
192.168.73.140	k8s-node2

可以直接选择git clone项目代码，也可以后面自己编写，后面的操作也会有实现代码

[root@k8s-master src]# git clone https://gitee.com/zhdya/K8S-Monitor.git
Cloning into 'k8s-prometheus'...
remote: Enumerating objects: 3, done.
remote: Counting objects: 100% (3/3), done.
remote: Total 3 (delta 0), reused 0 (delta 0), pack-reused 0
Unpacking objects: 100% (3/3), done.
[root@k8s-master src]# cd k8s-prometheus/
[root@k8s-master k8s-prometheus]# ls
alertmanager-configmap.yaml         kube-state-metrics-rbac.yaml             prometheus-rbac.yaml
alertmanager-deployment.yaml        kube-state-metrics-service.yaml          prometheus-rules.yaml
alertmanager-pvc.yaml               node_exporter-0.17.0.linux-amd64.tar.gz  prometheus-service.yaml
alertmanager-service.yaml           node_exporter.sh                         prometheus-statefulset-static-pv.yaml
grafana.yaml                        OWNERS                                   prometheus-statefulset.yaml
kube-state-metrics-deployment.yaml  prometheus-configmap.yaml                README.md

这些文件主要分为四部分，第一部分是 prometheus 的部署文件，包含了 configmap、rbac、service、statefulset，共四个文件，第二部分是 kube-state-metrics，获取资源对象的部署文件，第三部分为 node-exporter 部署文件，第四部分 alertmanager 部署文件，这个是用来告警的，开始部署吧，先部署 prometheus。

1.1、使用RBAC进行授权

首先需要部署 rbac、configmap

RBAC（Role-Based Access Control，基于角色的访问控制）：负责完成授权（Authorization）工作。

[root@k8s-master prometheus-k8s]# vim prometheus-rbac.yaml
apiVersion: v1
kind: ServiceAccount
metadata:
  name: prometheus
  namespace: kube-system
  labels:
    kubernetes.io/cluster-service: "true"

    addonmanager.kubernetes.io/mode: Reconcile
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRole
metadata:
  name: prometheus
  labels:
    kubernetes.io/cluster-service: "true"
    addonmanager.kubernetes.io/mode: Reconcile
rules:
  - apiGroups:
      - ""
    resources:
      - nodes
      - nodes/metrics
      - services
      - endpoints
      - pods
    verbs:
      - get
      - list
      - watch
  - apiGroups:
      - ""
    resources:
      - configmaps
    verbs:
      - get
  - nonResourceURLs:
      - "/metrics"
    verbs:
      - get
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
  name: prometheus
  labels:
    kubernetes.io/cluster-service: "true"
    addonmanager.kubernetes.io/mode: Reconcile
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: prometheus
subjects:
- kind: ServiceAccount
  name: prometheus
  namespace: kube-system

创建：

[root@k8s-master prometheus-k8s]# kubectl apply -f prometheus-rbac.yaml

1.2、配置管理

使用Configmap保存不需要加密配置信息其中需要把nodes中ip地址根据自己的地址进行修改，其他不需要改动。

[root@k8s-master prometheus-k8s]# vim prometheus-configmap.yaml
# Prometheus configuration format https://prometheus.io/docs/prometheus/latest/configuration/configuration/
apiVersion: v1
kind: ConfigMap #
metadata:
  name: prometheus-config
  namespace: kube-system
  labels:
    kubernetes.io/cluster-service: "true"
    addonmanager.kubernetes.io/mode: EnsureExists
data:
  prometheus.yml: |
    rule_files:
    - /etc/config/rules/*.rules

    scrape_configs:
    - job_name: prometheus
      static_configs:
      - targets:
        - localhost:9090

    - job_name: kubernetes-nodes
      scrape_interval: 30s
      static_configs:
      - targets:
        - 192.168.73.135:9100   #ip地址根据自己的地址进行修改
        - 192.168.73.138:9100
        - 192.168.73.139:9100
        - 192.168.73.140:9100

    - job_name: kubernetes-apiservers
      kubernetes_sd_configs:
      - role: endpoints
      relabel_configs:
      - action: keep
        regex: default;kubernetes;https
        source_labels:
        - __meta_kubernetes_namespace
        - __meta_kubernetes_service_name
        - __meta_kubernetes_endpoint_port_name
      scheme: https
      tls_config:
        ca_file: /var/run/secrets/kubernetes.io/serviceaccount/ca.crt
        insecure_skip_verify: true
      bearer_token_file: /var/run/secrets/kubernetes.io/serviceaccount/token

    - job_name: kubernetes-nodes-kubelet
      kubernetes_sd_configs:
      - role: node
      relabel_configs:
      - action: labelmap
        regex: __meta_kubernetes_node_label_(.+)
      scheme: https
      tls_config:
        ca_file: /var/run/secrets/kubernetes.io/serviceaccount/ca.crt
        insecure_skip_verify: true
      bearer_token_file: /var/run/secrets/kubernetes.io/serviceaccount/token

    - job_name: kubernetes-nodes-cadvisor
      kubernetes_sd_configs:
      - role: node
      relabel_configs:
      - action: labelmap
        regex: __meta_kubernetes_node_label_(.+)
      - target_label: __metrics_path__
        replacement: /metrics/cadvisor
      scheme: https
      tls_config:
        ca_file: /var/run/secrets/kubernetes.io/serviceaccount/ca.crt
        insecure_skip_verify: true
      bearer_token_file: /var/run/secrets/kubernetes.io/serviceaccount/token

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

    - job_name: kubernetes-services
      kubernetes_sd_configs:
      - role: service
      metrics_path: /probe
      params:
        module:
        - http_2xx
      relabel_configs:
      - action: keep
        regex: true
        source_labels:
        - __meta_kubernetes_service_annotation_prometheus_io_probe
      - source_labels:
        - __address__
        target_label: __param_target
      - replacement: blackbox
        target_label: __address__
      - 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

    - job_name: kubernetes-pods
      kubernetes_sd_configs:
      - role: pod
      relabel_configs:
      - action: keep
        regex: true
        source_labels:
        - __meta_kubernetes_pod_annotation_prometheus_io_scrape
      - action: replace
        regex: (.+)
        source_labels:
        - __meta_kubernetes_pod_annotation_prometheus_io_path
        target_label: __metrics_path__
      - action: replace
        regex: ([^:]+)(?::\d+)?;(\d+)
        replacement: $1:$2
        source_labels:
        - __address__
        - __meta_kubernetes_pod_annotation_prometheus_io_port
        target_label: __address__
      - action: labelmap
        regex: __meta_kubernetes_pod_label_(.+)
      - action: replace
        source_labels:
        - __meta_kubernetes_namespace
        target_label: kubernetes_namespace
      - action: replace
        source_labels:
        - __meta_kubernetes_pod_name
        target_label: kubernetes_pod_name
    alerting:
      alertmanagers:
      - static_configs:
          - targets: ["alertmanager:80"]

重点分析：

1、

rule_files:
- /etc/config/rules/*.rules

这是写入告警规则的目录，也就是这个configmap会挂载到普罗米修斯里面，让主进程读取这些配置；

2、

scrape_configs:
    - job_name: prometheus
      static_configs:
      - targets:
        - localhost:9090

如上这些都是来配置监控端的，job_name是分组，这是是监控它本身，下面还有监控node,我们会在node上起一个nodeport,这里修改要监控node节点。

[root@k8s-master prometheus-k8s]# kubectl apply -f prometheus-configmap.yaml

这里分为两块告警规则，一个是通用的告警规则，适用所有的实例，如果实例要是挂了，会发送告警，实例被监控端的agent，还有一个node角色，这个监控每个node的CPU、内存、磁盘利用率。

1.3、有状态部署prometheus

部署 prometheus 的方式为 statefulset，也就是有状态服务，这个也用到了 PV 动态供给，它默认的模板里指定了 storageClassName 类名为 managed-nfs-storage，也就是这里定义的，

[root@k8s-master prometheus-k8s]# vim prometheus-statefulset.yaml
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: prometheus
  namespace: kube-system
  labels:
    k8s-app: prometheus
    kubernetes.io/cluster-service: "true"
    addonmanager.kubernetes.io/mode: Reconcile
    version: v2.2.1
spec:
  serviceName: "prometheus"
  replicas: 1
  podManagementPolicy: "Parallel"
  updateStrategy:
   type: "RollingUpdate"
  selector:
    matchLabels:
      k8s-app: prometheus
  template:
    metadata:
      labels:
        k8s-app: prometheus
      annotations:
        scheduler.alpha.kubernetes.io/critical-pod: ''
    spec:
      priorityClassName: system-cluster-critical
      serviceAccountName: prometheus
      initContainers:
      - name: "init-chown-data"
        image: "busybox:latest"
        imagePullPolicy: "IfNotPresent"
        command: ["chown", "-R", "65534:65534", "/data"]
        volumeMounts:
        - name: prometheus-data
          mountPath: /data
          subPath: ""
      containers:
        - name: prometheus-server-configmap-reload
          image: "zhdya/configmap-reload:v0.1"
          imagePullPolicy: "IfNotPresent"
          args:
            - --volume-dir=/etc/config
            - --webhook-url=http://localhost:9090/-/reload
          volumeMounts:
            - name: config-volume
              mountPath: /etc/config
              readOnly: true
          resources:
            limits:
              cpu: 10m
              memory: 10Mi
            requests:
              cpu: 10m
              memory: 10Mi

        - name: prometheus-server
          image: "prom/prometheus:v2.2.1"
          imagePullPolicy: "IfNotPresent"
          args:
            - --config.file=/etc/config/prometheus.yml
            - --storage.tsdb.path=/data
            - --web.console.libraries=/etc/prometheus/console_libraries
            - --web.console.templates=/etc/prometheus/consoles
            - --web.enable-lifecycle
          ports:
            - containerPort: 9090
          readinessProbe:
            httpGet:
              path: /-/ready
              port: 9090
            initialDelaySeconds: 30
            timeoutSeconds: 30
          livenessProbe:
            httpGet:
              path: /-/healthy
              port: 9090
            initialDelaySeconds: 30
            timeoutSeconds: 30
          # based on 10 running nodes with 30 pods each
          resources:
            limits:
              cpu: 200m
              memory: 1000Mi
            requests:
              cpu: 200m
              memory: 1000Mi

          volumeMounts:
            - name: config-volume
              mountPath: /etc/config
            - name: prometheus-data
              mountPath: /data
              subPath: ""
            - name: prometheus-rules
              mountPath: /etc/config/rules

      terminationGracePeriodSeconds: 300
      volumes:
        - name: config-volume
          configMap:
            name: prometheus-config
        - name: prometheus-rules
          configMap:
            name: prometheus-rules

  volumeClaimTemplates:
  - metadata:
      name: prometheus-data
    spec:
      storageClassName: managed-nfs-storage #存储类根据自己的存储类名字修改
      accessModes:
        - ReadWriteOnce
      resources:
        requests:
          storage: "16Gi"

[root@k8s-master prometheus-k8s]# kubectl apply -f prometheus-statefulset.yaml

检查状态：

[root@k8s-master prometheus-k8s]# kubectl get pod -n kube-system
NAME                                    READY   STATUS    RESTARTS   AGE
prometheus-0                            2/2     Running   6          14d

1.4、创建service暴露访问端口

此处使用nodePort固定一个访问端口，不适用随机端口，便于访问

[root@k8s-master prometheus-k8s]# vim prometheus-service.yaml
kind: Service
apiVersion: v1
metadata:
  name: prometheus
  namespace: kube-system
  labels:
    kubernetes.io/name: "Prometheus"
    kubernetes.io/cluster-service: "true"
    addonmanager.kubernetes.io/mode: Reconcile
spec:
  type: NodePort
  ports:
    - name: http
      port: 9090
      protocol: TCP
      targetPort: 9090
      nodePort: 30090    #固定的对外访问的端口
  selector:
    k8s-app: prometheus

[root@k8s-master prometheus-k8s]# kubectl apply -f prometheus-service.yaml

[root@k8s-master prometheus-k8s]# kubectl get pod,svc -n kube-system
NAME                                        READY   STATUS    RESTARTS   AGE
pod/coredns-5bd5f9dbd9-wv45t                1/1     Running   1          8d
pod/kubernetes-dashboard-7d77666777-d5ng4   1/1     Running   5          14d
pod/prometheus-0                            2/2     Running   6          14d
NAME                           TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)             AGE
service/kube-dns               ClusterIP   10.0.0.2     <none>        53/UDP,53/TCP       13d
service/kubernetes-dashboard   NodePort    10.0.0.127   <none>        443:30001/TCP       16d
service/prometheus             NodePort    10.0.0.33    <none>        9090:30090/TCP      13d

web访问

使用任意一个NodeIP加端口进行访问，访问地址：http://NodeIP:Port ,此例就是：http://192.168.73.139:30090

二、基于 K8S 服务发现的配置解析

2.1、K8S集群资源监控

先看一下部署 prometheus 的部署文件，他是启动了两个容器，其中一个是这个：

- name: prometheus-server-configmap-reload
  image: "zhdya/configmap-reload:v0.1"
  imagePullPolicy: "IfNotPresent"

这个容器的作用是这样，当他发现 configmap 有更新的时候，会自动重载 prometheus，现在进入到 prometheus-server 容器中解析一下他的配置文件，先是这一段：

# kubectl exec -it -n kube-system prometheus-0 -c prometheus-server sh
/prometheus $ cat /etc/config/prometheus.yml
- job_name: kubernetes-apiservers
  kubernetes_sd_configs:
  - role: endpoints
  relabel_configs:
  - action: keep
    regex: default;kubernetes;https
    source_labels:
    - __meta_kubernetes_namespace
    - __meta_kubernetes_service_name
    - __meta_kubernetes_endpoint_port_name
  scheme: https
  tls_config:
    ca_file: /var/run/secrets/kubernetes.io/serviceaccount/ca.crt
    insecure_skip_verify: true
  bearer_token_file: /var/run/secrets/kubernetes.io/serviceaccount/token

job_name 为 kubernetes-apiservers，动态发现类型为 kubernetes_sd_configs，也就是基于 kubernetes 的服务发现，这一段的配置采集的是这个：

下面又使用了重新标记的标签，使用了keep，也就是只保留正则匹配的标签，源标签的值包含 default;kubernetes;https，我只采集这些，所以这一段的作用就是采集 kube-apiserver，使用的方法是 https，最后就是普罗米修斯访问apiserver 使用的 CA 和 token，这是两个默认的，任何一个pod都会有这两个文件，管理员权限，再下面：

- job_name: kubernetes-nodes-kubelet
  kubernetes_sd_configs:
  - role: node
  relabel_configs:
  - action: labelmap
    regex: __meta_kubernetes_node_label_(.+)
  scheme: https
  tls_config:
    ca_file: /var/run/secrets/kubernetes.io/serviceaccount/ca.crt
    insecure_skip_verify: true
  bearer_token_file: /var/run/secrets/kubernetes.io/serviceaccount/token

他是采集了每个节点的 10250/metrics，这个 10250 就是 kubelet 集成的 cAdvisor 单独暴露的端口，这个接口是采集kubelet本身暴露出来的一些指标，他的角色为 node，访问的方式还是 https，和上面的方式是一样的，再往下看：

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

这里是用来发现 endpoints 的，__开头的都是 prometheus 自有的，一般情况下不会直接使用，如果直接用的话需要重新打标签，看页面，目前只是采集到一个 coredns 的 endpoints，我目前 coredns 启动了两个：

所以你的 endpoints 想被prometheus抓取就需要加这个声明，是否被采集，采集的端口是什么，使用什么协议，都需要声明，再下面：

- job_name: kubernetes-services
  kubernetes_sd_configs:
  - role: service
  metrics_path: /probe
  params:
    module:
    - http_2xx
  relabel_configs:
  - action: keep
    regex: true
    source_labels:
    - __meta_kubernetes_service_annotation_prometheus_io_probe
  - source_labels:
    - __address__
    target_label: __param_target
  - replacement: blackbox
    target_label: __address__
  - 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

这里是黑盒探测 services 是否可用，这个之前没提过，他用了 blackbox 组件，探测路径为 /probe，http探测，下面的就不贴了，都是类似的东西了，prometheus 在采集你资源的时候用的值都是在被创建对象中动态获取的，也就是需要你去定义的。

2.2、监控集群中 pod

开始监控资源了，最重要的指标就是pod了，要想监控pod很简单，上面提到了监控 pod 需要使用 cAdvisor，而 cAdvisor 已经集成到 kubelet 中了，cAdvisor 会采集所有 pod 的指标，包括宿主机的内存CPU，cAdvisor有两个暴露地址，分别是 NodeIP:{10255,10250}/metrice/cadvisor，这是在kubelet配置文件中指定的，也就是这里：

port: 10250            #暴露kubelet自身指标端口
readOnlyPort: 10255    #单独cAdvisor端口

也就是如上的这张图：

K8S

Prometheus K8S

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