边车容器(sidecar)：边车容器就是与主容器一起在一个pod中运行的容器，为业务容器赋能，共享一个网络空间，所以可以用127.0.0.1:3306连接主容器的数据库 。一、背景：一开始的初衷是，想写一个脚本来监控服务器的高占用率进程并通过邮件发送给我，然后突发奇想，可以使用这种方式来备份我的数据库，开始动手！
二、设计思路：通过编写Shell脚本，调用linux的mAIl工具，MySQLDump的方式来保存数据库的sql文件，通过Mail工具添加到附件 ， 最后发送到我的邮箱 。
三、编写启动脚本首先我们来编写一个启动脚本 为了方便以后的个性化配置 ， 我们将脚本中的变量都提取到一个Application.yml文件中 ， 文件如下：
RUNTIME: 084900 HOST: 172.16.1.2USER: rootPORT: 3306PASSword: 123456DATABASE: deanTARGETMAIL: deanmr@qq.com接下来我们来写一下shell脚本，逻辑也很简单，当前时间与启动时间相同时，则调用sendmail函数发送邮件
#!/bin/bashRUNTIME=$(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 $2}')functionsendmail(){echo -e "mysqlbak_$CURRENT_TIME" |mail -s "mysqlbak_$CURRENT_TIME" -a $DATABASE.sql $TARGETMAILsleep 1}while truedoCURRENT_TIME=$(date +%H%M%S)if [ $CURRENT_TIME = $RUNTIME ];thenecho "starting bak mysql database"sendmailcontinueelseecho $CURRENT_TIMEsleep 1fidone四、构建镜像因为我们最后要放到k8s平台上的，所以我们要构建一个镜像，在构建镜像之前 ， 请先把application.yml demo.sh Dockerfile放在同一目录下 Dockerfile如下：PS:添加了mysql的客户端，邮件mail客户端
FROM centosRUN mkdir /app && yum install -y mysql.x86_64 sendmailmailx libreport-plugin-mailx WORKDIR /appCOPY demo.sh .COPY application.yml .CMD ["/bin/sh","demo.sh"]使用docker build命令构建镜像,要记得加一下最后的点
docker build -t mysqlmail-bak:1.0.1 .五、添加边车容器边车容器(sidecar)：边车容器就是与主容器一起在一个pod中运行的容器，为业务容器赋能，共享一个网络空间 ， 所以可以用127.0.0.1:3306连接主容器的数据库 。
5.1 创建配置文件为了方便调试，我把里面的shell脚本也挂载出来 。创建两个configmap，分别对应容器内的配置文件与shell脚本，后面如果不需要调试可以取消mysqlshell的挂载 。
apiVersion: v1kind: ConfigMapmetadata:name: mysqlmail-confnamespace: deandata:application.yml: |RUNTIME: 105800HOST: 127.0.0.1USER: rootPASSWORD: 123456DATABASE: deanTARGETMAIL: deanmr@qq.com---apiVersion: v1kind: ConfigMapmetadata:name: mysqlmail-shellnamespace: deandata:demo.sh: |#!/bin/bashRUNTIME=$(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 $2}')functionsendmail(){mysqldump -h$HOST-u$USER -p$PASSWORD--complete-insert --skip-add-drop-table--column-statistics=0 --hex-blob $DATABASE> $DATABASE.sqlecho -e "mysqlbak_$CURRENT_TIME" |mail -s "mysqlbak_$CURRENT_TIME" -a $DATABASE.sql $TARGETMAILsleep 1}while truedoCURRENT_TIME=$(date +%H%M%S)if [ $CURRENT_TIME = $RUNTIME ];thenecho "starting bak mysql database"sendmailcontinueelseecho $CURRENT_TIMEsleep 1fidone5.2 创建有状态服务部署文件【我们一起聊聊K8s定时备份MySQL并发送到指定邮箱】我们的deploy文件使用的是上篇文章中创建的mysql有状态服务的yaml
apiVersion: apps/v1kind: StatefulSetmetadata:name: mysqlnamespace: deanspec:serviceName: mysql-serviceselector:matchLabels:app: mysqlreplicas: 1template:metadata:labels:app: mysqlspec:containers:- name: mysqlmail-bakimagePullPolicy: IfNotPresentimage: mysqlmail-bak:1.0.1volumeMounts:- name: mysqlmail-confmountPath: /app/application.ymlsubPath: application.yml- name: mysqlmail-shellmountPath: /app/demo.shsubPath: demo.sh- name: mysql-podimagePullPolicy: IfNotPresentimage: mysql:5.7env:- name: MYSQL_ROOT_PASSWORDvalue: "123456"ports:- containerPort: 3306name: msyql-listinvolumeMounts:- name: mysql-datamountPath: /var/lib/mysqlsubPath: mysql-data- name: mysql-confmountPath: /etc/mysql/conf.d/my.cnfsubPath: my.cnfvolumes:- name: mysql-datahostPath:path: /data/mysql- name: mysql-confconfigMap:name: mysql-conf- name: mysqlmail-confconfigMap:name: mysqlmail-conf- name: mysqlmail-shellconfigMap:name: mysqlmail-shell---apiVersion: v1kind: Servicemetadata:name: mysql-servicenamespace: deanlabels:app: mysqlspec:ports:- targetPort: 3306port: 3306clusterIP: Noneselector:app: mysql