实战环境（CentOS7）

VIP      10.211.55.180
LVS1     10.211.55.151
LVS1     10.211.55.151
RS1      10.211.55.171
RS2      10.211.55.172


初始化环境所有节点
iptalbes -F       #清空防火墙
systemctl stop firewalld    #关闭防火墙
systemctl disable firewalld  #停止防火墙开机自启动
setenforce 0      #临时关闭selinux
sed -i 's/^SELINUX=.*$/SELINUX=disabled/g'  /etc/selinux/config    #关闭selinux
yum -y install epel-release     #安装epel源

LVS1、2操作

1、安装keepalived ipvsadm

yum -y install keepalived ipvsadm


[root@localhost ~]# lsmod |grep ip_vs     #检查ipvs模块
ip_vs_rr               12600  1
ip_vs                 145497  3 ip_vs_rr
nf_conntrack          139264  9 ip_vs,nf_nat,nf_nat_ipv4,nf_nat_ipv6,xt_conntrack,nf_nat_masquerade_ipv4,nf_conntrack_netlink,nf_conntrack_ipv4,nf_conntrack_ipv6
libcrc32c              12644  4 xfs,ip_vs,nf_nat,nf_conntrack 



2、配置keepalived  （LVS1、2）

2.1 修改keepalived的配置文件
[root@localhost ~]# cd /etc/keepalived/
[root@localhost keepalived]# cat keepalived.conf
! Configuration File for keepalived

global_defs {
   notification_email {
     314334451@
   }
   notification_email_from 314334451@
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
   vrrp_skip_check_adv_addr
#   vrrp_strict
   vrrp_garp_interval 0
   vrrp_gna_interval 0
}

vrrp_instance VI_1 {
    state MASTER                            #LVS1的这里是MASTER，则LVS2的改为BACKUP
    interface eth0
    virtual_router_id 51
    priority 100                            #LVS1的是100，则LVS2的为100以下就行，比如90，权重越大，VIP则飘在哪一边
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        10.211.55.180                       #VIP
    }
}

virtual_server 10.211.55.180 80 {          #VIP
    delay_loop 6
    lb_algo wrr      
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 10.211.55.171 80 {           #后端RS1检测,如有问题则移除服务器，不再往该服务器发送请求
        weight 1
        TCP_CHECK {
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
            connect_port 80
        }
    }
    real_server 10.211.55.172 80 {            #后端RS2检测，如有问题则移除服务器，不再往该服务器发送请求
        weight 1
        TCP_CHECK {
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
            connect_port 80
        }
    }
}


2.2 设置开机启动（LVS1、2）
systemctl enable keepalived
systemctl start keepalived


3、配置LVS，执行下面的脚本（LVS1、2），并把脚本设置为开机启动

vi /opt/lvs_dr.sh
#!/bin/sh
# description: Start LVS of Director server
VIP=192.168.30.100
RIP1=192.168.30.71
RIP2=192.168.30.72
case "$1" in
    start)
        echo " start LVS of Director Server"
# set the Virtual  IP Address and sysctl parameter
# /sbin/ifconfig eth0:0 $VIP broadcast $VIP netmask 255.255.255.255 up
# route add -host $VIP dev eth0:0
       echo "1" >/proc/sys/net/ipv4/ip_forward
#Clear IPVS table
       /sbin/ipvsadm -C
#set LVS
/sbin/ipvsadm -A -t $VIP:80 -s wrr # -p 600                #需要会话持久化则把此处的-p 600取消注释,或使用sh算法
/sbin/ipvsadm -a -t $VIP:80 -r $RIP1:80 -g -w1             #-g DR模式
/sbin/ipvsadm -a -t $VIP:80 -r $RIP2:80 -g -w1
#Run LVS
      /sbin/ipvsadm
       ;;
    stop)
        echo "close LVS Directorserver"
        echo "0" >/proc/sys/net/ipv4/ip_forward
        /sbin/ipvsadm -C
      #  /sbin/ifconfig eth0:0 down
        ;;
    *)
        echo "Usage: $0 {start|stop}"
        exit 1
esac

chmod +x /opt/lvs_dr.sh    #加执行权限

echo "/opt/lvs_dr.sh start" >>/etc/profile   #开机自启动


4、配置RS操作,执行下面操作（RS1、2）

安装nginx
yum -y install nginx #RS1、2 都安装

#配置测试页面
echo 10.211.55.171 >/usr/share/nginx/html/index.html    #RS1上操作
echo 10.211.55.172 >/usr/share/nginx/html/index.html    #RS2上操作


设置RS脚本，并设置开机自启动
vi /opt/lvs_rs.sh

#!/bin/bash
VIP=192.168.30.100
/sbin/ifconfig lo:0 $VIP broadcast $VIP netmask 255.255.255.255 up    #添加虚拟IP
/sbin/route add -host $VIP dev lo:0                                   #添加网关
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

#end
此操作是在回环设备上绑定了一个虚拟IP地址，并设定其子网掩码为255.255.255.255，与Director Server上的虚拟IP保持互通，然后禁止了本机的ARP请求。
由于虚拟ip，也就是上面的VIP地址，是Director Server和所有的Real server共享的，如果有ARP请求VIP地址时，Director Server与所有Real server都做应答的话，就出现问题了，因此，需要禁止Real server响应ARP请求。而lvsrs脚本的作用就是使Real Server不响应arp请求。

chmod + /opt/lvs_rs.sh  #加执行权限
echo "/opt/lvs_rs.sh "    #开机自启动


5、测试
找一个客户机,执行下面的命令
->$ for i in `seq 20`;do curl 10.211.55.180;done
10.211.55.171
10.211.55.172
10.211.55.171
10.211.55.172
10.211.55.171
10.211.55.172
10.211.55.171
10.211.55.172
10.211.55.171
10.211.55.172
10.211.55.171
10.211.55.172
10.211.55.171
10.211.55.172
10.211.55.171
10.211.55.172
10.211.55.171
10.211.55.172
10.211.55.171
10.211.55.172