我們一起聊聊K8s定時備份MySQL并發送到指定郵箱

作者：院長技術 2023-12-29 08:46:48

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邊車容器(sidecar)：邊車容器就是與主容器一起在一個pod中運行的容器，為業務容器賦能，共享一個網絡空間，所以可以用127.0.0.1:3306連接主容器的數據庫。

一、背景：

一開始的初衷是，想寫一個腳本來監控服務器的高占用率進程并通過郵件發送給我，然后突發奇想，可以使用這種方式來備份我的數據庫，開始動手！

二、設計思路：

通過編寫Shell腳本，調用Linux的mail工具，MySQLDump的方式來保存數據庫的sql文件，通過Mail工具添加到附件，最后發送到我的郵箱。

三、編寫啟動腳本

首先我們來編寫一個啟動腳本為了方便以后的個性化配置，我們將腳本中的變量都提取到一個application.yml文件中，文件如下：

RUNTIME: 084900 
HOST: 172.16.1.2
USER: root
PORT: 3306
PASSWORD: 123456
DATABASE: dean
TARGETMAIL: deanmr@qq.com

接下來我們來寫一下shell腳本，邏輯也很簡單，當前時間與啟動時間相同時，則調用sendmail函數發送郵件

#!/bin/bash

RUNTIME=$(cat ./application.yml | grep RUNTIME| awk '{print $2}')
HOST=$(cat ./application.yml | grep HOST| awk '{print $2}')
USER=$(cat ./application.yml | grep USER| awk '{print $2}')
PORT=$(cat ./application.yml | grep PORT| awk '{print $2}')
PASSWORD=$(cat ./application.yml | grep PASSWORD| awk '{print $2}')
DATABASE=$(cat ./application.yml | grep DATABASE| awk '{print $2}')
TARGETMAIL=$(cat ./application.yml | grep TARGETMAIL| awk '{print $2}')

function  sendmail(){
  echo -e "mysqlbak_$CURRENT_TIME" |mail -s "mysqlbak_$CURRENT_TIME" -a $DATABASE.sql $TARGETMAIL
  sleep 1
}
while true
do 
  CURRENT_TIME=$(date +%H%M%S)
  if [ $CURRENT_TIME = $RUNTIME ];then
    echo "starting bak mysql database"
    sendmail
    continue
  else
    echo $CURRENT_TIME
    sleep 1
  fi
done

四、構建鏡像

因為我們最后要放到k8s平臺上的，所以我們要構建一個鏡像，在構建鏡像之前，請先把application.yml demo.sh Dockerfile放在同一目錄下 Dockerfile如下：PS:添加了mysql的客戶端，郵件mail客戶端

FROM centos
RUN mkdir /app && yum install -y mysql.x86_64 sendmail  mailx libreport-plugin-mailx 
WORKDIR /app
COPY demo.sh .
COPY application.yml .
CMD ["/bin/sh","demo.sh"]

使用docker build命令構建鏡像,要記得加一下最后的點

docker build -t mysqlmail-bak:1.0.1 .

五、添加邊車容器

5.1 創建配置文件

為了方便調試，我把里面的shell腳本也掛載出來。創建兩個configmap，分別對應容器內的配置文件與shell腳本，后面如果不需要調試可以取消mysqlshell的掛載。

apiVersion: v1
kind: ConfigMap
metadata:
  name: mysqlmail-conf
  namespace: dean
data:
  application.yml: | 
    RUNTIME: 105800
    HOST: 127.0.0.1
    USER: root
    PASSWORD: 123456
    DATABASE: dean
    TARGETMAIL: deanmr@qq.com
---
apiVersion: v1
kind: ConfigMap
metadata:
  name: mysqlmail-shell
  namespace: dean
data:
  demo.sh: |
    #!/bin/bash
    RUNTIME=$(cat ./application.yml | grep RUNTIME| awk '{print $2}')
    HOST=$(cat ./application.yml | grep HOST| awk '{print $2}')
    USER=$(cat ./application.yml | grep USER| awk '{print $2}')
    PASSWORD=$(cat ./application.yml | grep PASSWORD| awk '{print $2}')
    DATABASE=$(cat ./application.yml | grep DATABASE| awk '{print $2}')
    TARGETMAIL=$(cat ./application.yml | grep TARGETMAIL| awk '{print $2}')    
    function  sendmail(){
      mysqldump -h$HOST  -u$USER -p$PASSWORD  --complete-insert --skip-add-drop-table  --column-statistics=0 --hex-blob $DATABASE  > $DATABASE.sql
      echo -e "mysqlbak_$CURRENT_TIME" |mail -s "mysqlbak_$CURRENT_TIME" -a $DATABASE.sql $TARGETMAIL
      sleep 1
    }
    while true
    do 
      CURRENT_TIME=$(date +%H%M%S)
      if [ $CURRENT_TIME = $RUNTIME ];then
        echo "starting bak mysql database"
        sendmail
        continue
      else
        echo $CURRENT_TIME
        sleep 1
      fi
    done

5.2 創建有狀態服務部署文件

我們的deploy文件使用的是上篇文章中創建的mysql有狀態服務的yaml

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: mysql
  namespace: dean
spec:
  serviceName: mysql-service
  selector:
    matchLabels:
      app: mysql
  replicas: 1
  template:
    metadata:
      labels:
        app: mysql
    spec:
      containers:
      - name: mysqlmail-bak
        imagePullPolicy: IfNotPresent
        image: mysqlmail-bak:1.0.1
        volumeMounts:
        - name: mysqlmail-conf
          mountPath: /app/application.yml
          subPath: application.yml
        - name: mysqlmail-shell
          mountPath: /app/demo.sh
          subPath: demo.sh
      - name: mysql-pod
        imagePullPolicy: IfNotPresent
        image: mysql:5.7
        env:
        - name: MYSQL_ROOT_PASSWORD
          value: "123456"
        ports:
        - containerPort: 3306
          name: msyql-listin
        volumeMounts:
        - name: mysql-data  
          mountPath: /var/lib/mysql
          subPath: mysql-data
        - name: mysql-conf
          mountPath: /etc/mysql/conf.d/my.cnf
          subPath: my.cnf
      volumes:
      - name: mysql-data
        hostPath:
          path: /data/mysql
      - name: mysql-conf
        configMap:
          name: mysql-conf
      - name: mysqlmail-conf
        configMap: 
          name: mysqlmail-conf
      - name: mysqlmail-shell
        configMap:
          name: mysqlmail-shell
---

apiVersion: v1
kind: Service
metadata:
  name: mysql-service
  namespace: dean
  labels:
    app: mysql
spec:
  ports:
  - targetPort: 3306
    port: 3306
  clusterIP: None
  selector:
     app: mysql

六、測試

我們上面給他定的時間是RUNTIME: 105800，上海時區也就是18點58分，我們來看一下效果查看日志，注意：當一個pod包含多個容器時，要使用 -c 參數指定查看哪個容器

[root@VM-24-15-centos solo]# kubectl logs -n solo mysql-0  -c mysqlmail-bak | grep mysql -C 5
105755
105756
105757
105758
105759
starting bak mysql database
mysqldump: [Warning] Using a password on the command line interface can be insecure.
105801
105802

從日志可以看到，郵件已經發送成功了！我們來去郵箱看一下，發現也已經成功了，至此我們的實驗完美完成！

責任編輯：武曉燕來源：院長技術

邊車容器郵箱 pod

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