一、keepalived安装

yum install keepalived -y

二、keepalived配置

/etc/keepalived/keepalived.conf

1、主配置文件

! Configuration File for keepalived

global_defs {
   router_id tianma157 ## 路由器标识符，每一个实例唯一标识
   script_user root
}

## 检查脚本
vrrp_script health-check {
   script   "/etc/keepalived/script/health_check.sh 10.110.13.158" ## 另一台keepalived的ip
   interval 5 ## 检查脚本的间隔时间，单位是秒
   fall     3
   rise     5
}

vrrp_instance NG_CONFIG_KEEP {
    state BACKUP
    interface ens192 ##网卡名
    virtual_router_id 230 ## 虚拟路由器标识符，VIP 后一段
    priority 100
    advert_int 3
    nopreempt
    garp_master_delay 30

    authentication {
        auth_type PASS
        auth_pass tm_keepalived_230 ## 集群通信密码，后数据为VIP 后一段
    }

    track_interface {
        ens192  ## 本机网卡名
    }

    virtual_ipaddress {
        10.110.13.230/24 dev ens192  ## VIP和对应的网卡名
    }

    track_script {
        health-check
    }
}

2、从配置文件

! Configuration File for keepalived

global_defs {
   router_id tianma158 ## 路由器标识符，每一个实例唯一标识
   script_user root
}

## 检查脚本
vrrp_script health-check {
   script   "/etc/keepalived/script/health_check.sh 10.110.13.157" ## 另一台keepalived的ip
   interval 5 ## 检查脚本的间隔时间，单位是秒
   fall     3
   rise     5
}

vrrp_instance NG_CONFIG_KEEP {
    state BACKUP
    interface ens192 ##网卡名
    virtual_router_id 230 ## 虚拟路由器标识符，VIP 后一段
    priority 95
    advert_int 3
    nopreempt
    garp_master_delay 30

    authentication {
        auth_type PASS
        auth_pass tm_keepalived_230 ## 集群通信密码，后数据为VIP 后一段
    }

    track_interface {
        ens192  ## 本机网卡名
    }

    virtual_ipaddress {
        10.110.13.230/24 dev ens192  ## VIP和对应的网卡名
    }

    track_script {
        health-check
    }
}

三、检测脚步

/etc/keepalived/script/health_check.sh

1、创建脚步目录

mkdir /etc/keepalived/script
chmod +x /etc/keepalived/script/health_check.sh

2、检测脚步

#!/bin/bash

# -------------------------------------------------------
# $Name:         health_check.sh
# $Version:      v1.0
# $Function:     keepalved检测逻辑
# $Author:       Liuzhousheng
# $Create Date:  2020-5-28 15:15
# $Description:  判断在什么情况下VIP在A/B二台主机上漂移
#                100 master
#                 95 slave
# -------------------------------------------------------


health_check()
{
    local datetime=$(date "+%F %T")
    local logfile='/var/log/keepalived-check.log'
    local keep_conf="/etc/keepalived/keepalived.conf"
    local role=$(grep 'priority' $keep_conf |grep -v '#' |awk '{print $2}')
    local nginx_status=$(netstat  -ntlp |grep -w 80|grep nginx |grep -v grep |wc -l)
    local vip=$(cat $keep_conf |grep 'dev' |sed -r 's!\s+([^/]+)/.*!\1!')
    local local_has_vip=$(ip addr show ens192 |grep -c "$vip")
    local gateways=$(ip r l |awk '/^def|via/ {print $3}' |egrep '^(10|192|172)\.'|sort |uniq)
    local another_keep_ip=$1

    # 根据权重定义本地keepalived角色
    if [ "$role" == "100" ]; then
        role="master"
    elif [ "$role" == "95" ]; then
        role="slave"
    fi

    # 检查server进程是否存活
    ha_msg="$datetime Nginx is shutdown"
    if [ $nginx_status -eq 0 ]; then
        echo -e "${ha_msg}. $local_has_vip" >>$logfile
        exit 1
    fi


    # 检查本地网络是否异常
    network_msg="$datetime Gateway is unreachable"
    for gateway in $gateways $another_keep_ip; do
        ping -W 1 -c 1 $gateway >/dev/null 2>&1
        if [ $? -ne 0 ]; then
            echo "${network_msg}, ${gateway}. $local_has_vip" >>$logfile
            stats="${stats}1"
        fi
    done
    if [ "$stats" == "11" ]; then
        exit 2
    fi

    return 0
}

health_check $1