综合案例：使用Configmap-reload动态热加载Configmap中的配置文件（三十七）

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综合案例：使用Configmap-reload动态热加载Configmap中的配置文件

文章目录

1.configmap-reload资源热更新机制

在k8s集群中，当configmap以volume的形式挂载到pod内时，更新configmap，k8s会自动将更改的配置文件内容同步到pod挂载的文件中，这个并不是立刻生效的，大约需要1分钟左右，实际案例中，如果应用程序支持热更新功能，所谓热更新就是通过http接口的方式就可以更新程序的配置，如果支持热更新机制就可以使用configmap-reload监控配置文件的变更，当配置文件变更后调用程序接口自动将应用程序进行更新

以prometheus为例配置当promet.yaml更新后立即进行热更新

注意：只有支持热更新的程序才能进行configmap-reload配置

整体实现思路：

​ 1.首先准备一个configmap资源，用于保存prometheus的配置文件

​ 2.准备一套pv、pvc，用于持久化prometheus监控系统的数据

​ 3.准备一个statfulset控制器跑prometheus pod，configmap-reload必须依靠固定的主机名，因此需要采用statfulset资源

​ 4.准备svc资源，用于在外部访问prometheus

​ 5.在所有k8s节点上部署node_exporter，用于prometheus采集数据

​ 6.编辑configmap资源增加k8s节点的配置内容，观察configmap-reload是否会自动更新

2.使用configmap-reload实现prometheus监控系统配置热更新

2.1.准备prometheus的configmap资源

将prometheus配置文件以configmap的方式挂载到容器中

1.编写yaml
[root@k8s-master ~/k8s_1.19_yaml/configmap]# vim prometheus-configmap.yaml
apiVersion: v1
kind: ConfigMap
metadata:
  name: prometheus-configmap
  namespace: prometheus
data:
  prometheus.yaml: |
    global:
      scrape_interval:     90s
      evaluation_interval: 90s
    scrape_configs:
    - job_name: prometheus
      static_configs:
      - targets:
        - 127.0.0.1:9090

2.创建yaml
[root@k8s-master ~/k8s_1.19_yaml/configmap]# kubectl create -f prometheus-configmap.yaml
configmap/prometheus-configmap created

3.查看资源状态
[root@k8s-master ~/k8s_1.19_yaml/configmap]# kubectl get cm -n prometheus
NAME                   DATA   AGE
prometheus-configmap   1      4m56s

4.查看资源的详细信息
[root@k8s-master ~/k8s_1.19_yaml/configmap]# kubectl describe cm -n prometheus
Name:         prometheus-configmap
Namespace:    prometheus
Labels:       <none>
Annotations:  <none>

Data
====
prometheus.yaml:
----
global:
  scrape_interval:     90s
  evaluation_interval: 90s
scrape_configs:
- job_name: prometheus
  static_configs:
  - targets:
    - 127.0.0.1:9090

Events:  <none>

2.2.准备prometheus pv、pvc资源

为prometheus数据提供持久化存储

1.编写yaml
[root@k8s-master ~/k8s_1.19_yaml/configmap]# vim prometheus-pv.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv-2
  labels:
    pv: pv-2
spec:
  capacity:
    storage: 5Gi
  accessModes:
  - ReadWriteMany
  persistentVolumeReclaimPolicy: Retain
  nfs:												#以nfs类型存储
    path: /data/pv_2/prometheus
    server: 192.168.81.210

---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pvc-2
  namespace: prometheus
spec:
  accessModes:
  - ReadWriteMany
  resources:
    requests:
      storage: 5Gi
  selector:
    matchLabels:
      pv: pv-2							#通过标签方式管理pv-2的pv存储

2.创建资源
[root@k8s-master ~/k8s_1.19_yaml/configmap]# kubectl create -f prometheus-pv.yaml
persistentvolume/pv-2 created
persistentvolumeclaim/pvc-2 created

2.3.编写prometheus statfulset、svc资源

使用statefulset资源控制器部署prometheus容器并使用svc进行暴露，由于configmap-reload必须要配合固定的主机名进行使用，因此采用statefulset控制器

1.编写statfulset控制器yaml文件
[root@k8s-master ~/k8s_1.19_yaml/configmap]# vim prometheus-statfulset.yaml 
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: statefulset-prometheus
  namespace: prometheus
spec:
  serviceName: "prometheus"
  replicas: 1
  podManagementPolicy: "Parallel"
  updateStrategy:
   type: "RollingUpdate"
  selector:
    matchLabels:
      app: prometheus-pod
  template:
    metadata:
      labels:
        app: prometheus-pod
    spec:
      initContainers:									#定义一个初始化容器，主要是给/data目录赋权限并挂载pvc
      - name: "init-chown-data"
        image: "busybox:1.30"
        command: ["chown", "-R", "65534:65534", "/data"]
        volumeMounts:
        - name: prometheus-data 
          mountPath: /data
      containers: 
      - name: prometheus
        image: prom/prometheus:v2.23.0
        args:								#定义prometheus启动参数
          - --config.file=/etc/config/prometheus.yaml
          - --storage.tsdb.path=/data
          - --web.console.libraries=/etc/prometheus/console_libraries
          - --web.console.templates=/etc/prometheus/consoles
          - --web.enable-lifecycle					#启动prometheus热更新机制
        ports:
        - containerPort: 9090
        volumeMounts:
        - name: prometheus-data
          mountPath: /data
        - name: prometheus-config
          mountPath: /etc/config
      volumes:
        - name: prometheus-data
          persistentVolumeClaim:
            claimName: pvc-2
            readOnly: false
        - name: prometheus-config
          configMap:
            name: prometheus-configmap

2.编写service资源的yaml文件
[root@k8s-master ~/k8s_1.19_yaml/configmap]# vim prometheus-svc.yaml
apiVersion: v1
kind: Service
metadata:
  name: prometheus-service
  namespace: prometheus
spec:
  selector:
    app: prometheus-pod
  type: NodePort
  ports:
  - port: 9090
    targetPort: 9090

3.创建资源
[root@k8s-master ~/k8s_1.19_yaml/configmap]# kubectl create -f prometheus-statfulset.yaml
statefulset.apps/statefulset-prometheus created

[root@k8s-master ~/k8s_1.19_yaml/configmap]# kubectl create -f prometheus-svc.yaml
service/prometheus-service created

2.4.访问prometheus

1.查看prometheus创建的资源
[root@k8s-master ~/k8s_1.19_yaml/configmap]# kubectl get all -n prometheus 
NAME                           READY   STATUS    RESTARTS   AGE
pod/statefulset-prometheus-0   1/1     Running   1          133m

NAME                         TYPE       CLUSTER-IP     EXTERNAL-IP   PORT(S)          AGE
service/prometheus-service   NodePort   10.99.144.79   <none>        9090:30877/TCP   134m

NAME                                      READY   AGE
statefulset.apps/statefulset-prometheus   1/1     134m


2.访问node节点ip加30877即可访问prometheus

在这里插入图片描述

2.5.配置configmap热更新

主要用来当configmap资源文件更新后，prometheus pod会自动加载配置并进行更新

1.修改yaml文件增加configmap-reload配置
[root@k8s-master ~/k8s_1.19_yaml/configmap]# vim prometheus-statfulset.yaml
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: statefulset-prometheus
  namespace: prometheus
spec:
  serviceName: "prometheus"
  replicas: 1
  podManagementPolicy: "Parallel"
  updateStrategy:
   type: "RollingUpdate"
  selector:
    matchLabels:
      app: prometheus-pod
  template:
    metadata:
      labels:
        app: prometheus-pod
    spec:
      initContainers:
      - name: "init-chown-data"
        image: "busybox:1.30"
        command: ["chown", "-R", "65534:65534", "/data"]
        volumeMounts:
        - name: prometheus-data 
          mountPath: /data
      containers: 
      - name: prometheus-configmap-reload						#增加一个configmap-reload的容器即可
        image: "jimmidyson/configmap-reload:v0.1"				
        imagePullPolicy: "IfNotPresent"
        args: 												#configmap-reload需要增加的参数
          - --volume-dir=/etc/prometheus
          - --webhook-url=http://localhost:9090/-/reload 
        volumeMounts:									#将configmap挂载到/etc/prometheus
          - name: prometheus-config
            mountPath: /etc/prometheus
            readOnly: true
      - name: prometheus
        image: prom/prometheus:v2.23.0
        args:
          - --config.file=/etc/config/prometheus.yaml
          - --storage.tsdb.path=/data
          - --web.console.libraries=/etc/prometheus/console_libraries
          - --web.console.templates=/etc/prometheus/consoles
          - --web.enable-lifecycle
        ports:
        - containerPort: 9090
        volumeMounts:
        - name: prometheus-data
          mountPath: /data
        - name: prometheus-config
          mountPath: /etc/config
      volumes:
        - name: prometheus-data
          persistentVolumeClaim:
            claimName: pvc-2
            readOnly: false
        - name: prometheus-config
          configMap:
            name: prometheus-configmap
            
2.更新yaml文件      
[root@k8s-master ~/k8s_1.19_yaml/configmap]# kubectl apply -f prometheus-statfulset.yaml 
statefulset.apps/statefulset-prometheus configured

2.6.更新configmap配置文件观察prometheus容器是否会自动更新

在node节点安装node_exporter监控采集器，并修改prometheus configmap的配置，等待一段时间后观察prometheus是否会自动更新配置

1.所有master、node节点安装并启动node_exporter
tar xf node_exporter-1.0.1.linux-amd64.tar.gz 
cp node_exporter-1.0.1.linux-amd64/node_exporter /usr/bin/
nohup /usr/bin/node_exporter &
netstat -lnpt | grep 9100

2.修改configmap中prometheus配置文件的内容增加node节点的配置
#这里只增加了master和node-1节点
[root@k8s-master ~/k8s_1.19_yaml/configmap]# vim prometheus-configmap.yaml 
apiVersion: v1
kind: ConfigMap
metadata:
  name: prometheus-configmap
  namespace: prometheus
data:
  prometheus.yaml: |
    global:
      scrape_interval:     90s
      evaluation_interval: 90s
    scrape_configs:
    - job_name: prometheus
      static_configs:
      - targets:
        - 127.0.0.1:9090
    - job_name: k8s-node
      static_configs:
      - targets:
        - 192.168.81.210:9100
        - 192.168.81.220:9100

3.更新configmap资源
[root@k8s-master ~/k8s_1.19_yaml/configmap]# kubectl apply -f prometheus-configmap.yaml 
configmap/prometheus-configmap configured

4.访问prometheus观察配置是否更新
直接在页面上查看prometheus的配置是否增加和targets里面是否有主机增加就可以看到效果了

在这里插入图片描述

本图文内容来源于网友网络收集整理提供，作为学习参考使用，版权属于原作者。
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