Docker+keepalived+nginx实现主从热备的方法示例

mkdir /etc/keepalivedcp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/然后复制keepalived脚本文件：cp /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/ln -s /usr/local/sbin/keepalived /usr/sbin/可以设置开机启动：chkconfig keepalived on，到此我们安装完毕!

#若启动报错，则执行下面命令
cd /usr/sbin/
rm -f keepalived
cp /usr/local/keepalived/sbin/keepalived /usr/sbin/

#常用命令
systemctl daemon-reload 重新加载systemctl enable keepalived.service 设置开机自动启动systemctl disable keepalived.service 取消开机自动启动systemctl start keepalived.service 启动systemctl stop keepalived.service停止systemctl status keepalived.service 查看服务状态

10,修改/etc/keepalived/keepalived.conf文件

#备份配置文件
cp /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.backup
rm -f keepalived.conf
vim keepalived.conf
#配置文件如下
vrrp_script chk_nginx {
  script "/etc/keepalived/nginx_check.sh"
  interval 2
  weight -20
}
vrrp_instance VI_1 {
  state MASTER
  interface eth0
  virtual_router_id 121
  mcast_src_ip 172.17.0.6
  priority 100
  nopreempt
  advert_int 1
  authentication {
    auth_type PASS
    auth_pass 1111
  }
  track_script {
    chk_nginx
  }
  virtual_ipaddress {
    172.17.0.100
  }
}

11,添加心跳检测文件

vim nginx_check.sh
#以下是脚本内容
#!/bin/bash
A=`ps -C nginx –no-header |wc -l`
if [ $A -eq 0 ];then
  /usr/local/nginx/sbin/nginx
  sleep 2
  if [ `ps -C nginx --no-header |wc -l` -eq 0 ];then
    killall keepalived
  fi
fi

12,给脚本赋予执行权限

chmod +x nginx_check.sh

13,设置开机启动

systemctl enable keepalived.service
#开启keepalived
systemctl start keepalived.service

14,检测虚拟IP是否成功,在宿主机里面执行下面命令，如果出现nginx欢迎界面表示成功

curl 172.17.0.100

15，将centos_temp 容器重新打包成镜像，然后利用这个新镜像再创建两个容器，实现热备效果

docker commit -a 'cfh' -m 'centos with keepalived nginx' centos_temp centos_kn

16,删除所有容器

docker rm -f `docker ps -a -q`

17，用centos_kn 镜像创建主服务器容器