Kubernetes系列之kubernetes Prometheus Operator

Kubernetes系列之kubernetes Prometheus Operator

Operator是由CoreOS公司开发的用来扩展Kubernetes API的特定应用程序控制器，用来创建、配置和管理复杂的有状态应用，例如Mysql、缓存和监控系统。目前CoreOS官方提供了几种Operator的代码实现，其中就包括Prometheus Operator

下图为Prometheus Operator 架构图

Operator作为一个核心的控制器，它会创建Prometheus、ServiceMonitor、alertmanager以及我们的prometheus-rule这四个资源对象，operator会一直监控并维持这四个资源对象的状态，其中创建Prometheus资源对象就是作为Prometheus Server进行监控，而ServiceMonitor就是我们用的exporter的各种抽象（exporter前面文章已经介绍了，就是提供我们各种服务的metrics的工具）Prometheus就是通过ServiceMonitor提供的metrics数据接口把我们数据pull过来的。现在我们监控prometheus不需要每个服务单独创建修改规则。通过直接管理Operator来进行集群的监控。这里还要说一下，一个ServiceMonitor可以通过我们的label标签去匹配集群内部的service，而我们的prometheus也可以通过label匹配多个ServiceMonitor

其中，Operator是核心部分，作为一个控制器而存在，Operator会创建Prometheus、ServiceMonitor、AlertManager及PrometheusRule这4个CRD资源对象，然后一直监控并维持这4个CRD资源对象的状态

• Prometheus 资源对象是作为Prometheus Service存在的
• ServiceMonitor 资源对象是专门提供metrics数据接口的exporter的抽象，Prometheus就是通过ServiceMonitor提供的metrics数据接口去 pull 数据的
• AlerManager 资源对象是对应alertmanager组件
• PrometheusRule 资源对象是被Prometheus实例使用的告警规则文件

CRD简介
全称CustomResourceDefinition，在Kubernetes中一切都可视为资源，在Kubernetes1.7之后增加对CRD自定义资源二次开发能力开扩展Kubernetes API，当我们创建一个新的CRD时，Kubernetes API服务器将为你制定的每个版本创建一个新的RESTful资源路径，我们可以根据该API路径来创建一些我们自己定义的类型资源。CRD可以是命名空间，也可以是集群范围。由CRD的作用域scpoe字段中所制定的，与现有的内置对象一样，删除名称空间将删除该名称中的所有自定义对象

简单的来说CRD是对Kubernetes API的扩展，Kubernetes中的每个资源都是一个API对象的集合，例如yaml文件中定义spec那样，都是对Kubernetes中资源对象的定义，所有的自定义资源可以跟Kubernetes中内建的资源一样使用Kubectl

这样，在集群中监控数据，就变成Kubernetes直接去监控资源对象，Service和ServiceMonitor都是Kubernetes的资源对象，一个ServiceMonitor可以通过labelSelector匹配一类Service，Prometheus也可以通过labelSelector匹配多个ServiceMonitor，并且Prometheus和AlertManager都是自动感知监控告警配置的变化，不需要认为进行reload操作。

---

安装

Operator是原生支持Prometheus的，可以通过服务发现来监控集群，并且是通用安装。也就是operator提供的yaml文件，基本上在Prometheus是可以直接使用的，需要改动的地方可能就只有几处

#官方下载 (使用官方下载的出现镜像版本不相同请自己找镜像版本)
wget -P /root/ https://github.com/coreos/kube-prometheus/archive/master.zip
unzip master.zip
cd /root/kube-prometheus-master/manifests

prometheus-serviceMonitorKubelet.yaml (这个文件是用来收集我们service的metrics数据的)

不需要修改

cat prometheus-serviceMonitorKubelet.yaml

apiVersion: monitoring.coreos.com/v1
kind: ServiceMonitor
metadata:
  labels:
    k8s-app: kubelet
  name: kubelet
  namespace: monitoring
spec:
  endpoints:
  - bearerTokenFile: /var/run/secrets/kubernetes.io/serviceaccount/token
    honorLabels: true
    interval: 30s
    port: https-metrics
    scheme: https
    tlsConfig:
      insecureSkipVerify: true
  - bearerTokenFile: /var/run/secrets/kubernetes.io/serviceaccount/token
    honorLabels: true
    interval: 30s
    metricRelabelings:
    - action: drop
      regex: container_(network_tcp_usage_total|network_udp_usage_total|tasks_state|cpu_load_average_10s)
      sourceLabels:
      - __name__
    path: /metrics/cadvisor
    port: https-metrics
    scheme: https
    tlsConfig:
      insecureSkipVerify: true
  jobLabel: k8s-app
  namespaceSelector:      #匹配命名空间，这个代表的意思就是会去匹配kube-system命名空间下，具有k8s-app=kubelet的标签，会将匹配的标签纳入我们prometheus监控中
    matchNames:
    - kube-system
  selector:             #这三行是用来匹配我们的service
    matchLabels:
      k8s-app: kubelet

这里修改完毕后，我们就可以直接创建配置文件

[root@HUOBAN-K8S-MASTER01 manifests]# kubectl apply -f ./
namespace/monitoring unchanged
customresourcedefinition.apiextensions.k8s.io/alertmanagers.monitoring.coreos.com unchanged
customresourcedefinition.apiextensions.k8s.io/podmonitors.monitoring.coreos.com unchanged
customresourcedefinition.apiextensions.k8s.io/prometheuses.monitoring.coreos.com unchanged
customresourcedefinition.apiextensions.k8s.io/prometheusrules.monitoring.coreos.com unchanged
customresourcedefinition.apiextensions.k8s.io/servicemonitors.monitoring.coreos.com unchanged
clusterrole.rbac.authorization.k8s.io/prometheus-operator unchanged
clusterrolebinding.rbac.authorization.k8s.io/prometheus-operator unchanged
deployment.apps/prometheus-operator unchanged
service/prometheus-operator unchanged
serviceaccount/prometheus-operator unchanged
servicemonitor.monitoring.coreos.com/prometheus-operator created
alertmanager.monitoring.coreos.com/main created
secret/alertmanager-main unchanged
service/alertmanager-main unchanged
serviceaccount/alertmanager-main unchanged
servicemonitor.monitoring.coreos.com/alertmanager created
secret/grafana-datasources unchanged
configmap/grafana-dashboard-apiserver unchanged
configmap/grafana-dashboard-controller-manager unchanged
configmap/grafana-dashboard-k8s-resources-cluster unchanged
configmap/grafana-dashboard-k8s-resources-namespace unchanged
configmap/grafana-dashboard-k8s-resources-node unchanged
configmap/grafana-dashboard-k8s-resources-pod unchanged
configmap/grafana-dashboard-k8s-resources-workload unchanged
configmap/grafana-dashboard-k8s-resources-workloads-namespace unchanged
configmap/grafana-dashboard-kubelet unchanged
configmap/grafana-dashboard-node-cluster-rsrc-use unchanged
configmap/grafana-dashboard-node-rsrc-use unchanged
configmap/grafana-dashboard-nodes unchanged
configmap/grafana-dashboard-persistentvolumesusage unchanged
configmap/grafana-dashboard-pods unchanged
configmap/grafana-dashboard-prometheus-remote-write unchanged
configmap/grafana-dashboard-prometheus unchanged
configmap/grafana-dashboard-proxy unchanged
configmap/grafana-dashboard-scheduler unchanged
configmap/grafana-dashboard-statefulset unchanged
configmap/grafana-dashboards unchanged
deployment.apps/grafana configured
service/grafana unchanged
serviceaccount/grafana unchanged
servicemonitor.monitoring.coreos.com/grafana created
clusterrole.rbac.authorization.k8s.io/kube-state-metrics unchanged
clusterrolebinding.rbac.authorization.k8s.io/kube-state-metrics unchanged
deployment.apps/kube-state-metrics unchanged
role.rbac.authorization.k8s.io/kube-state-metrics unchanged
rolebinding.rbac.authorization.k8s.io/kube-state-metrics unchanged
service/kube-state-metrics unchanged
serviceaccount/kube-state-metrics unchanged
servicemonitor.monitoring.coreos.com/kube-state-metrics created
clusterrole.rbac.authorization.k8s.io/node-exporter unchanged
clusterrolebinding.rbac.authorization.k8s.io/node-exporter unchanged
daemonset.apps/node-exporter configured
service/node-exporter unchanged
serviceaccount/node-exporter unchanged
servicemonitor.monitoring.coreos.com/node-exporter created
apiservice.apiregistration.k8s.io/v1beta1.metrics.k8s.io unchanged
clusterrole.rbac.authorization.k8s.io/prometheus-adapter unchanged
clusterrole.rbac.authorization.k8s.io/system:aggregated-metrics-reader unchanged
clusterrolebinding.rbac.authorization.k8s.io/prometheus-adapter unchanged
clusterrolebinding.rbac.authorization.k8s.io/resource-metrics:system:auth-delegator unchanged
clusterrole.rbac.authorization.k8s.io/resource-metrics-server-resources unchanged
configmap/adapter-config unchanged
deployment.apps/prometheus-adapter configured
rolebinding.rbac.authorization.k8s.io/resource-metrics-auth-reader unchanged
service/prometheus-adapter unchanged
serviceaccount/prometheus-adapter unchanged
clusterrole.rbac.authorization.k8s.io/prometheus-k8s unchanged
clusterrolebinding.rbac.authorization.k8s.io/prometheus-k8s unchanged
prometheus.monitoring.coreos.com/k8s created
rolebinding.rbac.authorization.k8s.io/prometheus-k8s-config unchanged
rolebinding.rbac.authorization.k8s.io/prometheus-k8s unchanged
rolebinding.rbac.authorization.k8s.io/prometheus-k8s unchanged
rolebinding.rbac.authorization.k8s.io/prometheus-k8s unchanged
role.rbac.authorization.k8s.io/prometheus-k8s-config unchanged
role.rbac.authorization.k8s.io/prometheus-k8s unchanged
role.rbac.authorization.k8s.io/prometheus-k8s unchanged
role.rbac.authorization.k8s.io/prometheus-k8s unchanged
prometheusrule.monitoring.coreos.com/prometheus-k8s-rules created
service/prometheus-k8s unchanged
serviceaccount/prometheus-k8s unchanged
servicemonitor.monitoring.coreos.com/prometheus created
servicemonitor.monitoring.coreos.com/kube-apiserver created
servicemonitor.monitoring.coreos.com/coredns created
servicemonitor.monitoring.coreos.com/kube-controller-manager created
servicemonitor.monitoring.coreos.com/kube-scheduler created
servicemonitor.monitoring.coreos.com/kubelet created

当我们部署成功之后，我们可以查看一下crd,yaml文件会自动帮我们创建crd文件。只有我们创建了crd文件，我们的serviceMonitor才会有用

[root@HUOBAN-K8S-MASTER01 manifests]# kubectl get crd
NAME                                    CREATED AT
alertmanagers.monitoring.coreos.com     2019-10-18T08:32:57Z
podmonitors.monitoring.coreos.com       2019-10-18T08:32:58Z
prometheuses.monitoring.coreos.com      2019-10-18T08:32:58Z
prometheusrules.monitoring.coreos.com   2019-10-18T08:32:58Z
servicemonitors.monitoring.coreos.com   2019-10-18T08:32:59Z

其他的资源文件都会部署在一个命名空间下面，在monitoring里面是operator Pod对应的列表

[root@HUOBAN-K8S-MASTER01 manifests]# kubectl get pod -n monitoring
NAME                                  READY   STATUS    RESTARTS   AGE
alertmanager-main-0                   2/2     Running   0          11m
alertmanager-main-1                   2/2     Running   0          11m
alertmanager-main-2                   2/2     Running   0          11m
grafana-55488b566f-g2sm9              1/1     Running   0          11m
kube-state-metrics-ff5cb7949-wq7pb    3/3     Running   0          11m
node-exporter-6wb5v                   2/2     Running   0          11m
node-exporter-785rf                   2/2     Running   0          11m
node-exporter-7kvkp                   2/2     Running   0          11m
node-exporter-85bnh                   2/2     Running   0          11m
node-exporter-9vxwf                   2/2     Running   0          11m
node-exporter-bvf4r                   2/2     Running   0          11m
node-exporter-j6d2d                   2/2     Running   0          11m
prometheus-adapter-668748ddbd-d8k7f   1/1     Running   0          11m
prometheus-k8s-0                      3/3     Running   1          11m
prometheus-k8s-1                      3/3     Running   1          11m
prometheus-operator-55b978b89-qpzfk   1/1     Running   0          11m

其中prometheus和alertmanager采用的StatefulSet，其他的Pod则采用deployment创建

[root@HUOBAN-K8S-MASTER01 manifests]# kubectl get deployments.apps -n monitoring
NAME                  READY   UP-TO-DATE   AVAILABLE   AGE
grafana               1/1     1            1           12m
kube-state-metrics    1/1     1            1           12m
prometheus-adapter    1/1     1            1           12m
prometheus-operator   1/1     1            1           12m
[root@HUOBAN-K8S-MASTER01 manifests]# kubectl get statefulsets.apps -n monitoring
NAME                READY   AGE
alertmanager-main   3/3     11m
prometheus-k8s      2/2     11m

#其中prometheus-operator是我们的核心文件，它是监控我们prometheus和alertmanager的文件

现在创建完成后我们还无法直接访问prometheus

[root@HUOBAN-K8S-MASTER01 manifests]# kubectl get svc -n monitoring |egrep  "prometheus|grafana|alertmanage"
alertmanager-main       ClusterIP   10.96.226.38            9093/TCP                     3m55s
alertmanager-operated   ClusterIP   None                    9093/TCP,9094/TCP,9094/UDP   3m10s
grafana                 ClusterIP   10.97.175.234           3000/TCP                     3m53s
prometheus-adapter      ClusterIP   10.96.43.155            443/TCP                      3m53s
prometheus-k8s          ClusterIP   10.105.75.186           9090/TCP                     3m52s
prometheus-operated     ClusterIP   None                    9090/TCP                     3m
prometheus-operator     ClusterIP   None                    8080/TCP                     3m55s

由于默认的yaml文件svc采用的是ClusterIP，我们无法进行访问。这里我们可以使用ingress进行代理，或者使用node-port临时访问。我这里就修改一下svc，使用node-port进行访问

#我这里使用edit进行修改，或者修改yaml文件apply下即可

kubectl edit svc -n monitoring prometheus-k8s
#注意修改的svc是prometheus-k8s因为这个有clusterIP
kubectl edit svc -n monitoring grafana
kubectl edit svc -n monitoring alertmanager-main
#三个文件都需要修改，不要修改错了。都是修改有clusterIP的
...
  type: NodePort   #将这行修改为NodePort

prometheus-k8s、grafana和alertmanager-main都是只修改type=clusterIP这行

修改完毕后，我们在查看svc，就会发现这几个都包含node端口了，接下来在任意集群节点访问即可

[root@HUOBAN-K8S-MASTER01 manifests]# kubectl get svc -n monitoring |egrep  "prometheus|grafana|alertmanage"
alertmanager-main       NodePort    10.96.226.38            9093:32477/TCP               13m
alertmanager-operated   ClusterIP   None                    9093/TCP,9094/TCP,9094/UDP   12m
grafana                 NodePort    10.97.175.234           3000:32474/TCP               13m
prometheus-adapter      ClusterIP   10.96.43.155            443/TCP                      13m
prometheus-k8s          NodePort    10.105.75.186           9090:32489/TCP               13m
prometheus-operated     ClusterIP   None                    9090/TCP                     12m
prometheus-operator     ClusterIP   None                    8080/TCP                     13m

接下来我们查看prometheus的Ui界面

[root@HUOBAN-K8S-MASTER01 manifests]# kubectl get svc -n monitoring |grep prometheus-k8s
prometheus-k8s          NodePort    10.105.75.186           9090:32489/TCP               19m
[root@HUOBAN-K8S-MASTER01 manifests]# hostname -i
172.16.17.191

我们访问的集群172.16.17.191:32489

这里kube-controller-manager和kube-scheduler并管理的目标，其他的都有。这里的就是和官方yaml文件里面定义的有关系

配置文件解释

# vim prometheus-serviceMonitorKubeScheduler.yaml
apiVersion: monitoring.coreos.com/v1    #kubectl get crd里面包含的，不进行修改
kind: ServiceMonitor
metadata:
  labels:
    k8s-app: kube-scheduler
  name: kube-scheduler              #定义的名称
  namespace: monitoring             
spec:
  endpoints:
  - interval: 30s
    port: http-metrics              #这里定义的就是在svc上的端口名称
  jobLabel: k8s-app
  namespaceSelector:            #表示匹配哪一个命名空间，配置any:true则回去所有命名空间中查询
    matchNames:
    - kube-system
  selector:         #这里大概意思就是匹配kube-system命名空间下具有k8s-app=kube-scheduler标签的svc
    matchLabels:
      k8s-app: kube-scheduler