高可用示例

两台nginx操作

关闭防火墙及selinux

systemctl stop firewalld 
setenforce 0

创建ARP冲突检测脚本

vi /etc/init.d/realserver

#!/bin/bash
# description:Script to start LVS DR real server.
. /etc/rc.d/init.d/functions
VIP=192.168.32.100

#修改相应的VIP
case "$1" in
    start)
        #启动 LVS-DR 模式，real server on this machine. 关闭ARP冲突检测。
        echo "Start LVS of Real Server!"
        /sbin/ifconfig lo down
        /sbin/ifconfig lo up
        echo 1 > /proc/sys/net/ipv4/conf/lo/arp_ignore
        echo 2 > /proc/sys/net/ipv4/conf/lo/arp_announce
        echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore
        echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce
        /sbin/ifconfig lo:0 $VIP broadcast $VIP netmask 255.255.255.255 up
        /sbin/route add -host $VIP dev lo:0
        sudo sysctl -p
    ;;

    stop)
        #停止LVS-DR real server loopback device(s).
        echo "Close LVS Director Server!"
        /sbin/ifconfig lo:0 down
        echo 0 > /proc/sys/net/ipv4/conf/lo/arp_ignore
        echo 0 > /proc/sys/net/ipv4/conf/lo/arp_announce
        echo 0 > /proc/sys/net/ipv4/conf/all/arp_ignore
        echo 0 > /proc/sys/net/ipv4/conf/all/arp_announce
        sudo sysctl -p
    ;;
    
    status)
        # Status of LVS-DR real server.
        islothere=`/sbin/ifconfig lo:0 | grep $VIP`
        isrothere=`netstat -rn | grep "lo:0" | grep $VIP`
        if [ ! "$islothere" -o ! "isrothere" ];then
        # Either the route or the lo:0 device
        # not found.
            echo "LVS-DR real server Stopped!"
        else
            echo "LVS-DR real server Running..."
        fi
    ;;
    
    *)
        # Invalid entry.
        echo "$0: Usage: $0 {start|status|stop}"
        exit 1
    ;;

esac

关闭ARP冲突检测

chmod +x /etc/init.d/realserver 
chmod +x /etc/rc.d/init.d/functions
service realserver start

安装nginx

sudo rpm -Uvh http://nginx.org/packages/centos/7/noarch/RPMS/nginx-release-centos-7-0.el7.ngx.noarch.rpm
yum install -y nginx

修改页面及启动

echo 'ip: 192.168.32.137' > /usr/share/nginx/html/index.html 
systemctl start nginx

两个keepalived主机

关闭防火墙及selinux

systemctl stop firewalld 
setenforce 0

下载安装包

yum install -y keepalived ipvsadm

修改keepalive master配置

mv /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak
vi /etc/keepalived/keepalived.conf

global_defs {
   smtp_server 127.0.0.1
}

vrrp_instance VI_1 {
    state MASTER          #指定Keepalived的角色，MASTER为主，BACKUP为备 记得大写
    interface ens33       #网卡id 不同的电脑网卡id会有区别 可以使用:ip a查看
    virtual_router_id 51  #虚拟路由编号，主备要一致
    priority 100          #定义优先级，数字越大，优先级越高，主DR必须大于备用DR
    advert_int 1          #检查间隔，默认为1s
    authentication {      #这里配置的密码最多为8位，主备要一致，否则无法正常通讯
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.32.100    #定义虚拟IP(VIP)为192.168.1.200，可多设，每行一个
    }
}

# 定义对外提供服务的LVS的VIP以及port
virtual_server 192.168.32.100 443 {
    delay_loop 6          # 设置健康检查时间，单位是秒
    lb_algo wlc           # 设置负载调度的算法为wlc
    lb_kind DR            # 设置LVS实现负载的机制，有NAT、TUN、DR三个模式
    nat_mask 255.255.255.0
    persistence_timeout 0
    protocol TCP
    real_server 192.168.32.137 443 {  # 指定real server1的IP地址
        weight 3   # 配置节点权值，数字越大权重越高
        TCP_CHECK {
        connect_timeout 10
        nb_get_retry 3
        delay_before_retry 3
        connect_port 443
        }
    }
    real_server 192.168.32.145 443 {  # 指定real server2的IP地址
        weight 3  # 配置节点权值，数字越大权重越高
        TCP_CHECK {
        connect_timeout 10
        nb_get_retry 3
        delay_before_retry 3
        connect_port 443
        }
     }
}

修改keepalived backup配置

mv /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak
vi /etc/keepalived/keepalived.conf

global_defs {
   smtp_server 127.0.0.1
}

vrrp_instance VI_1 {
    state BACKUP #指定Keepalived的角色，MASTER为主，BACKUP为备 记得大写
    interface ens33  #网卡id 不同的电脑网卡id会有区别 可以使用:ip a查看
    virtual_router_id 51  #虚拟路由编号，主备要一致
    priority 50  #定义优先级，数字越大，优先级越高，主DR必须大于备用DR
    advert_int 1  #检查间隔，默认为1s
    authentication {   #这里配置的密码最多为8位，主备要一致，否则无法正常通讯
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.32.100  #定义虚拟IP(VIP)为192.168.1.200，可多设，每行一个
    }
}

# 定义对外提供服务的LVS的VIP以及port
virtual_server 192.168.32.100 443 {
    delay_loop 6 # 设置健康检查时间，单位是秒
    lb_algo wlc  # 设置负载调度的算法为wlc
    lb_kind DR   # 设置LVS实现负载的机制，有NAT、TUN、DR三个模式
    nat_mask 255.255.255.0
    persistence_timeout 0
    protocol TCP
    real_server 192.168.32.137 443 {  # 指定real server1的IP地址
        weight 3   # 配置节点权值，数字越大权重越高
        TCP_CHECK {
        connect_timeout 10
        nb_get_retry 3
        delay_before_retry 3
        connect_port 443
        }
    }

    real_server 192.168.32.145 443 {  # 指定real server2的IP地址
        weight 3  # 配置节点权值，数字越大权重越高
        TCP_CHECK {
        connect_timeout 10
        nb_get_retry 3
        delay_before_retry 3
        connect_port 443
        }
     }
}

启动服务

systemctl start keepalived