使用keepalived搭建nginx高可用

1、主机  master   192.168.8.154    备用机backup 192.168.8.100    VIP：192.168.8.180   (关闭selinux、iptables  -F)

yum  -y  install   keepalived  nginx

编辑master上keepalived配置文件

# vim /etc/keepalived/keepalived.conf
global_defs {
   notification_email {
     951687336@qq..com
   }
   notification_email_from 951687336@qq.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 MASTER
    interface ens33
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass aminglinux>com
    }
    virtual_ipaddress {
        192.168.8.180
    }

    track_script {
        chk_nginx
    }

}

编辑vim   /etc/init.d/nginx

#!/bin/bash
# chkconfig: - 30 21
# description: http service.
# Source Function Library
. /etc/init.d/functions
# Nginx Settings

NGINX_SBIN="/usr/local/nginx/sbin/nginx"
NGINX_CONF="/usr/local/nginx/conf/nginx.conf"
NGINX_PID="/usr/local/nginx/logs/nginx.pid"
RETVAL=0
prog="Nginx"

start() {
        echo -n $"Starting $prog: "
        mkdir -p /dev/shm/nginx_temp
        daemon $NGINX_SBIN -c $NGINX_CONF
        RETVAL=$?
        echo
        return $RETVAL
}

stop() {
        echo -n $"Stopping $prog: "
        killproc -p $NGINX_PID $NGINX_SBIN -TERM
        rm -rf /dev/shm/nginx_temp
        RETVAL=$?
        echo
        return $RETVAL
}

reload(){
        echo -n $"Reloading $prog: "
        killproc -p $NGINX_PID $NGINX_SBIN -HUP
        RETVAL=$?
        echo
        return $RETVAL
}

restart(){
        stop
        start
}

configtest(){
    $NGINX_SBIN -c $NGINX_CONF -t
    return 0
}

case "$1" in
  start)
        start
        ;;
  stop)
        stop
        ;;
  reload)
        reload
        ;;
  restart)
        restart
        ;;
  configtest)
        configtest
        ;;
  *)
        echo $"Usage: $0 {start|stop|reload|restart|configtest}"
        RETVAL=1
esac

exit $RETVAL

定义nginx的监控脚本 vim   /usr/local/sbin/check_ng.sh

#!/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

chmod  a+x  /usr/local/sbin/check_ng.sh

配置完成，启动service  keepalived start  ，ip addr 可以产看网卡中的虚拟ip

配置backup

vim /etc/keepalived/keepalived.conf

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 eth0
    virtual_router_id 51
    priority 90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass aminglinux>com
    }
    virtual_ipaddress {
        192.168.8.180
    }

    track_script {
        chk_nginx
    }

}

配置nginx检测   vim /usr/local/sbin/check_ng.sh

#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

启动service  keepalived  start   （能够拉动nginx启动）