linux学习第五十六篇：集群介绍，keepalived介绍，用keepalived配置高可用集群

global_defs {
   notification_email {
     aming@aminglinux.com //出现问题时给指定邮箱发邮件
   }
   notification_email_from root@aminglinux.com //由哪一个邮件发出去
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
}
vrrp_script chk_nginx {
    script "/usr/local/sbin/check_ng.sh"   //检测服务是否正常
    interval 3  //检测间断3秒钟
}
vrrp_instance VI_1 {
    state MASTER  
    interface ens33 //通过vrrp协议去发广播，通过指定网卡去发，这里的网卡是ens33
    virtual_router_id 51 //定义路由器的ID
    priority 100
    advert_int 1
    authentication { //认证相关的信息
        auth_type PASS
        auth_pass aminglinux>com
    }
    virtual_ipaddress {  //VIP，如果主宕机了，从马上绑定定义的这个VIP
        192.168.188.100 //这个IP可以在主上用ip add命令查看
    }
    track_script {
        chk_nginx  //加载检查脚本
    }
}

#!/bin/bash
#时间变量，用于记录日志
d=`date --date today +%Y%m%d_%H:%M:%S`
#计算nginx进程数量
n=`ps -C nginx --no-heading|wc -l`
#如果进程为0，则启动nginx，并且再次检测nginx进程数量，
#如果还为0，说明nginx无法启动，此时需要关闭keepalived
if [ $n -eq "0" ]; then
        /etc/init.d/nginx start
        n2=`ps -C nginx --no-heading|wc -l`
        if [ $n2 -eq "0"  ]; then
                echo "$d nginx down,keepalived will stop" >> /var/log/check_ng.log
                systemctl stop keepalived
        fi
fi

global_defs {
   notification_email {
     aming@aminglinux.com
   }
   notification_email_from root@aminglinux.com
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
}
vrrp_script chk_nginx {
    script "/usr/local/sbin/check_ng.sh"
    interval 3
}
vrrp_instance VI_1 {
    state BACKUP
    interface ens33
    virtual_router_id 51
    priority 90 //主上是100，这里是90，优先级
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass aminglinux>com
    }
    virtual_ipaddress {
        192.168.188.100  //跟主上的IP一样
    }
    track_script {
        chk_nginx
    }
}

#时间变量，用于记录日志
d=`date --date today +%Y%m%d_%H:%M:%S`
#计算nginx进程数量
n=`ps -C nginx --no-heading|wc -l`
#如果进程为0，则启动nginx，并且再次检测nginx进程数量，
#如果还为0，说明nginx无法启动，此时需要关闭keepalived
if [ $n -eq "0" ]; then
        systemctl start nginx
        n2=`ps -C nginx --no-heading|wc -l`
        if [ $n2 -eq "0"  ]; then
                echo "$d nginx down,keepalived will stop" >> /var/log/check_ng.log
                systemctl stop keepalived
        fi
fi