一、介紹
Operator是CoreOS公司開發,用于擴充kubernetes API或特定應用程式的控制器,它用來建立、配置、管理複雜的有狀态應用,例如資料庫,監控系統。其中Prometheus-Operator就是其中一個重要的項目。
其架構圖如下:

其中核心部分是Operator,它會去建立Prometheus、ServiceMonitor、AlertManager、PrometheusRule這4個CRD對象,然後會一直監控并維護這4個對象的狀态。
- Prometheus:作為Prometheus Server的抽象
- ServiceMonitor:就是exporter的各種抽象
- AlertManager:作為Prometheus AlertManager的抽象
- PrometheusRule:實作報警規則的檔案
上圖中的 Service 和 ServiceMonitor 都是 Kubernetes 的資源,一個 ServiceMonitor 可以通過 labelSelector 的方式去比對一類 Service,Prometheus 也可以通過 labelSelector 去比對多個ServiceMonitor。
二、安裝
注意叢集版本的坑,自己先到Github上下載下傳對應的版本。
我們使用源碼來安裝,首先克隆源碼到本地:
# git clone https://github.com/coreos/kube-prometheus.git
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我們進入kube-prometheus/manifests/setup,就可以直接建立CRD對象:
# cd kube-prometheus/manifests/setup
# kubectl apply -f .
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然後在上層目錄建立資源清單:
# cd kube-prometheus/manifests
# kubectl apply -f .
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可以看到建立如下的CRD對象:
# kubectl get crd | grep coreos
alertmanagers.monitoring.coreos.com 2019-12-02T03:03:37Z
podmonitors.monitoring.coreos.com 2019-12-02T03:03:37Z
prometheuses.monitoring.coreos.com 2019-12-02T03:03:37Z
prometheusrules.monitoring.coreos.com 2019-12-02T03:03:37Z
servicemonitors.monitoring.coreos.com 2019-12-02T03:03:37Z
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檢視建立的pod:
# kubectl get pod -n monitoring
NAME READY STATUS RESTARTS AGE
alertmanager-main-0 2/2 Running 0 2m37s
alertmanager-main-1 2/2 Running 0 2m37s
alertmanager-main-2 2/2 Running 0 2m37s
grafana-77978cbbdc-886cc 1/1 Running 0 2m46s
kube-state-metrics-7f6d7b46b4-vrs8t 3/3 Running 0 2m45s
node-exporter-5552n 2/2 Running 0 2m45s
node-exporter-6snb7 2/2 Running 0 2m45s
prometheus-adapter-68698bc948-6s5f2 1/1 Running 0 2m45s
prometheus-k8s-0 3/3 Running 1 2m27s
prometheus-k8s-1 3/3 Running 1 2m27s
prometheus-operator-6685db5c6-4tdhp 1/1 Running 0 2m52s
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檢視建立的Service:
# kubectl get svc -n monitoring
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
alertmanager-main ClusterIP 10.68.97.247 <none> 9093/TCP 3m51s
alertmanager-operated ClusterIP None <none> 9093/TCP,9094/TCP,9094/UDP 3m41s
grafana ClusterIP 10.68.234.173 <none> 3000/TCP 3m50s
kube-state-metrics ClusterIP None <none> 8443/TCP,9443/TCP 3m50s
node-exporter ClusterIP None <none> 9100/TCP 3m50s
prometheus-adapter ClusterIP 10.68.109.201 <none> 443/TCP 3m50s
prometheus-k8s ClusterIP 10.68.9.232 <none> 9090/TCP 3m50s
prometheus-operated ClusterIP None <none> 9090/TCP 3m31s
prometheus-operator ClusterIP None <none> 8080/TCP 3m57s
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我們看到我們常用的prometheus和grafana都是clustorIP,我們要外部通路可以配置為NodePort類型或者用ingress。比如配置為ingress:prometheus-ingress.yaml
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: prometheus-ingress
namespace: monitoring
annotations:
kubernetes.io/ingress.class: "traefik"
spec:
rules:
- host: prometheus.joker.com
http:
paths:
- path:
backend:
serviceName: prometheus-k8s
servicePort: 9090
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grafana-ingress.yaml
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: grafana-ingress
namespace: monitoring
annotations:
kubernetes.io/ingress.class: "traefik"
spec:
rules:
- host: grafana.joker.com
http:
paths:
- path:
backend:
serviceName: grafana
servicePort: 3000
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但是我們這裡由于沒有域名進行備案,我們就用NodePort類型。修改後如下:
# kubectl get svc -n monitoring
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
grafana NodePort 10.68.234.173 <none> 3000:39807/TCP 3h1m 3h1m
prometheus-k8s NodePort 10.68.9.232 <none> 9090:20547/TCP 3h1m
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然後就可以正常在浏覽器通路了。
三、配置
3.1、監控叢集資源
我們可以看到大部分的配置都是正常的,隻有兩三個沒有管理到對應的監控目标,比如 kube-controller-manager 和 kube-scheduler 這兩個系統元件,這就和 ServiceMonitor 的定義有關系了,我們先來檢視下 kube-scheduler 元件對應的 ServiceMonitor 資源的定義:(prometheus-serviceMonitorKubeScheduler.yaml)
apiVersion: monitoring.coreos.com/v1
kind: ServiceMonitor
metadata:
labels:
k8s-app: kube-scheduler
name: kube-scheduler
namespace: monitoring
spec:
endpoints:
- interval: 30s # 每30s擷取一次資訊
port: http-metrics # 對應service的端口名
jobLabel: k8s-app
namespaceSelector: # 表示去比對某一命名空間中的service,如果想從所有的namespace中比對用any: true
matchNames:
- kube-system
selector: # 比對的 Service 的labels,如果使用mathLabels,則下面的所有标簽都比對時才會比對該service,如果使用matchExpressions,則至少比對一個标簽的service都會被選擇
matchLabels:
k8s-app: kube-scheduler
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上面是一個典型的 ServiceMonitor 資源檔案的聲明方式,上面我們通過selector.matchLabels在 kube-system 這個命名空間下面比對具有k8s-app=kube-scheduler這樣的 Service,但是我們系統中根本就沒有對應的 Service,是以我們需要手動建立一個 Service:(prometheus-kubeSchedulerService.yaml)
apiVersion: v1
kind: Service
metadata:
namespace: kube-system
name: kube-scheduler
labels:
k8s-app: kube-scheduler
spec:
selector:
component: kube-scheduler
ports:
- name: http-metrics
port: 10251
targetPort: 10251
protocol: TCP
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10251是元件 metrics 資料所在的端口,10252是
kube-scheduler
元件的監控資料所在端口。
kube-controller-manager
其中最重要的是上面 labels 和 selector 部分,labels 區域的配置必須和我們上面的 ServiceMonitor 對象中的 selector 保持一緻,selector下面配置的是component=kube-scheduler,為什麼會是這個 label 标簽呢,我們可以去 describe 下 kube-scheduelr 這個 Pod:
$ kubectl describe pod kube-scheduler-master -n kube-system
Name: kube-scheduler-master
Namespace: kube-system
Node: master/10.151.30.57
Start Time: Sun, 05 Aug 2018 18:13:32 +0800
Labels: component=kube-scheduler
tier=control-plane
......
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我們可以看到這個 Pod 具有component=kube-scheduler和tier=control-plane這兩個标簽,而前面這個标簽具有更唯一的特性,是以使用前面這個标簽較好,這樣上面建立的 Service 就可以和我們的 Pod 進行關聯了,直接建立即可:
$ kubectl create -f prometheus-kubeSchedulerService.yaml
$ kubectl get svc -n kube-system -l k8s-app=kube-scheduler
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kube-scheduler ClusterIP 10.102.119.231 <none> 10251/TCP 18m
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建立完成後,隔一小會兒後去 prometheus 檢視 targets 下面 kube-scheduler 的狀态:
promethus kube-scheduler error我們可以看到現在已經發現了 target,但是抓取資料結果出錯了,這個錯誤是因為我們叢集是使用 kubeadm 搭建的,其中 kube-scheduler 預設是綁定在127.0.0.1上面的,而上面我們這個地方是想通過節點的 IP 去通路,是以通路被拒絕了,我們隻要把 kube-scheduler 綁定的位址更改成0.0.0.0即可滿足要求,由于 kube-scheduler 是以靜态 Pod 的形式運作在叢集中的,是以我們隻需要更改靜态 Pod 目錄下面對應的 YAML 檔案即可:
$ ls
etcd.yaml kube-apiserver.yaml kube-controller-manager.yaml kube-scheduler.yaml
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将 kube-scheduler.yaml 檔案中-command的--address位址更改成0.0.0.0:
containers:
- command:
- kube-scheduler
- --leader-elect=true
- --kubeconfig=/etc/kubernetes/scheduler.conf
- --address=0.0.0.0
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修改完成後我們将該檔案從目前檔案夾中移除,隔一會兒再移回該目錄,就可以自動更新了,然後再去看 prometheus 中 kube-scheduler 這個 target 是否已經正常了:
promethues-operator-kube-scheduler大家可以按照上面的方法嘗試去修複下 kube-controller-manager 元件的監控。
3.2、監控叢集外資源
很多時候我們并不是把所有資源都部署在叢集内的,經常有比如ectd,kube-scheduler等都部署在叢集外。其監控流程和上面大緻一樣,唯一的差別就是在定義Service的時候,其EndPoints是需要我們自己去定義的。
3.2.1、監控kube-scheduler
(1)、定義Service和EndPointsprometheus-KubeSchedulerService.yaml
apiVersion: v1
kind: Service
metadata:
name: kube-scheduler
namespace: kube-system
labels:
k8s-app: kube-scheduler
spec:
type: ClusterIP
clusterIP: None
ports:
- name: http-metrics
port: 10251
targetPort: 10251
protocol: TCP
---
apiVersion: v1
kind: Endpoints
metadata:
name: kube-scheduler
namespace: kube-system
labels:
k8s-app: kube-scheduler
subsets:
- addresses:
- ip: 172.16.0.33
ports:
- name: http-metrics
port: 10251
protocol: TCP
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(2)、定義ServiceMonitorprometheus-serviceMonitorKubeScheduler.yaml
apiVersion: monitoring.coreos.com/v1
kind: ServiceMonitor
metadata:
name: kube-scheduler
namespace: monitoring
labels:
k8s-app: kube-scheduler
spec:
endpoints:
- interval: 30s
port: http-metrics
jobLabel: k8s-app
namespaceSelector:
matchNames:
- kube-system
selector:
matchLabels:
k8s-app: kube-scheduler
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然後我們就可以看到其監控上了:
3.2.2、監控kube-controller-manager
(1)、配置Service和EndPoints,prometheus-KubeControllerManagerService.yaml
apiVersion: v1
kind: Service
metadata:
name: kube-controller-manager
namespace: kube-system
labels:
k8s-app: kube-controller-manager
spec:
type: ClusterIP
clusterIP: None
ports:
- name: http-metrics
port: 10252
targetPort: 10252
protocol: TCP
---
apiVersion: v1
kind: Endpoints
metadata:
name: kube-controller-manager
namespace: kube-system
labels:
k8s-app: kube-controller-manager
subsets:
- addresses:
- ip: 172.16.0.33
ports:
- name: http-metrics
port: 10252
protocol: TCP
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apiVersion: monitoring.coreos.com/v1
kind: ServiceMonitor
metadata:
labels:
k8s-app: kube-controller-manager
name: kube-controller-manager
namespace: monitoring
spec:
endpoints:
- interval: 30s
metricRelabelings:
- action: drop
regex: etcd_(debugging|disk|request|server).*
sourceLabels:
- __name__
port: http-metrics
jobLabel: k8s-app
namespaceSelector:
matchNames:
- kube-system
selector:
matchLabels:
k8s-app: kube-controller-manager
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