实验环境

（1）本次基于VMware Workstation搭建一个四台Linux（CentOS 7.4）系统所构成的一个服务器集群，其中两台负载均衡服务器（一台为主机，另一台为备机），另外两台作为真实的Web服务器（向外部提供http服务，这里仅仅使用了CentOS默认自带的http服务，没有安装其他的类似Tomcat、Jexus服务）。

　　（2）本次实验基于DR负载均衡模式，设置了一个VIP（Virtual IP）为172.18.38.99，用户只需要访问这个IP地址即可获得网页服务。其中，负载均衡主机为172.18.38.100，备机为172.18.38.101。Web服务器A为172.18.38.200，Web服务器B为172.18.38.201。

实验准备

(1)，绑定静态IP地址

[root@centos7-100 ~]# nmcli connection modify ens37 ipv4.addresses 172.18.38.100/16 ipv4.method manual connection.autoconnect yes     [root@centos7-101 ~]# nmcli connection modify ens37 ipv4.addresses 172.18.38.101/16 ipv4.method manual connection.autoconnect yes     [root@centos7-200 ~]# nmcli connection modify ens37 ipv4.addresses 172.18.38.200/16 ipv4.method manual connection.autoconnect yes     [root@centos7-201 ~]# nmcli connection modify ens37 ipv4.addresses 172.18.38.201/16 ipv4.method manual connection.autoconnect yes

(2)，同步时间

利用chronyd服务同步时间

1，在四台主机上都执行下面的命令，注意时间服务器必须是一台

1，修改配置文件     vim /etc/chrony.conf        # Please consider joining the pool (http://www.pool.ntp.org/join.html).        server 172.18.0.1  iburst #指定一台服务器    2，利用下面这条命令概略同步一下      ntpdate 172.18.0.1      1 Apr 13:23:31 ntpdate[8517]: adjust time server 172.18.0.1 offset -0.350642 sec    3，重启chrony服务     systemctl restart chronyd.service

(3)，关闭防火墙

systemctl disable firewalld    systemctl stop firewalld

(3)，LVS+keepalived主从配置

1，在两台lvs服务器下载keepalived

yum  -y install keepalived

1，keepvlived_master+lvs配置文件

vim /etc/keepalived/keepalived.conf     ! Configuration File for keepalived    global_defs {       notification_email {         root@localhost   #出问题了发邮件给谁       }       notification_email_from keepalived@localhost       smtp_server 127.0.0.1 #本机邮件服务器       smtp_connect_timeout 30 #超时时间       router_id proxy1  #服务器id       vrrp_mcast_group4 224.1.1.1 #多播地址所有的keepalived会在这个地址通讯，决定谁工作    }    vrrp_instance VI_1 {        state MASTER  #主服务器        interface ens37 #网卡接口        virtual_router_id 66 #服务器id        priority 100  #优先级，        advert_int 1 #心跳检测 1秒一次        authentication { #验证            auth_type PASS  #验证类型，基于密码            auth_pass 123456 #密码        }        virtual_ipaddress {            172.18.38.99/16 #共享IP        }    }    virtual_server 172.18.38.99 80 {        delay_loop 6          lb_algo rr  #调度算法        lb_kind DR  #调度模型        #persistence_timeout 50         protocol TCP         sorry_server 127.0.0.1 80         real_server 172.18.38.200 80 {  #后端server_IP 及端口            weight 1  #权重            HTTP_GET {  #健康检测方式                url {                  path /                  status_code 200                  }                connect_timeout 3 #超时时间                nb_get_retry 3 #重试次数                delay_before_retry 3 #多长时间重试            }        }        real_server 172.18.38.201 80 {            weight 1            HTTP_GET {                url {                  path /                  status_code 200                }                connect_timeout 3                nb_get_retry 3                delay_before_retry 3            }        }    }

2，keepalived_slave+lvs配置

vim /etc/keepalived/keepalived.conf    ! Configuration File for keepalived    global_defs {       notification_email {         root@localhost       }       notification_email_from keepalived@localhost       smtp_server 127.0.0.1       smtp_connect_timeout 30       router_id proxy1       vrrp_mcast_group4 224.1.1.1    }    vrrp_instance VI_2 {        state SLAVE  "slave关键配置"        interface ens37        virtual_router_id 88        priority 80        advert_int 1        authentication {            auth_type PASS            auth_pass 123456        }        virtual_ipaddress {            172.18.38.99/16        }    }    virtual_server 172.18.38.99 80 {        delay_loop 6        lb_algo rr        lb_kind DR        #persistence_timeout 50        protocol TCP        sorry_server 127.0.0.1 80        real_server 172.18.38.200 80 {            weight 1            HTTP_GET {                url {                  path /                  status_code 200                }                connect_timeout 3                nb_get_retry 3                delay_before_retry 3            }        }        real_server 172.18.38.201 80 {            weight 1            HTTP_GET {                url {                  path /                  status_code 200                }                connect_timeout 3                nb_get_retry 3                delay_before_retry 3            }        }    }

3，在两台lvs服务器下载ipvsadm包

yum install ipvsadm

4，在两台lvs主机上都启动keepalived服务

systemctl start keepalived    systemctl enable keepalived

5，注意这时候会在ens37网卡上加上一个新的IP

[root@centos7-lvs_master ~]# ip a         ens37: 
    
      mtu 1500 qdisc pfifo_fast state UP qlen 1000    link/ether 00:50:56:39:48:cc brd ff:ff:ff:ff:ff:ff    inet 172.18.38.101/16 brd 172.18.255.255 scope global ens37       valid_lft forever preferred_lft forever    inet 172.18.38.99/16 scope global secondary ens37       valid_lft forever preferred_lft forever    inet6 fe80::a7b9:b100:4f55:480e/64 scope link        valid_lft forever preferred_lft forever[root@centos7-lvs_slave  ~]# ip a         ens37: 
     
       mtu 1500 qdisc pfifo_fast state UP qlen 1000            link/ether 00:50:56:39:48:cc brd ff:ff:ff:ff:ff:ff            inet 172.18.38.101/16 brd 172.18.255.255 scope global ens37                 valid_lft forever preferred_lft forever            inet 172.18.38.99/16 scope global secondary ens37                 valid_lft forever preferred_lft forever            inet6 fe80::a7b9:b100:4f55:480e/64 scope link                  valid_lft forever preferred_lft forever
     
    

5，查看调度规则

[root@centos7-lvs_master ~]# ipvsadm -ln    IP Virtual Server version 1.2.1 (size=4096)    Prot LocalAddress:Port Scheduler Flags      -> RemoteAddress:Port           Forward Weight ActiveConn InActConn    TCP  172.18.38.99:80 rr      -> 172.18.38.200:80             Route   1      0          4               -> 172.18.38.201:80             Route   1      0          4        [root@centos7-lvs_slave  ~]# ipvsadm -ln    IP Virtual Server version 1.2.1 (size=4096)    Prot LocalAddress:Port Scheduler Flags      -> RemoteAddress:Port           Forward Weight ActiveConn InActConn    TCP  172.18.38.99:80 rr      -> 172.18.38.200:80             Route   1      0          0               -> 172.18.38.201:80             Route   1      0          0

(4)，配置2个后端web服务器

1，安装httpd软件

1，安装httpd软件    yum install http    2，启动服务        systemctl start httpd        systemctl enable httpd    2，生成web页面，        A主机            echo web_server_A > /var/www/html/index.html        b主机            echo web_server_B > /var/www/html/index.html

2，在两个web服务器执行下面的脚本，会在lo网卡上生成一个vip

vim lvs_br_rs.sh    #!/bin/bash    #Author:wangxiaochun    #Date:2017-08-13    vip=172.18.38.99   "只需要修改一下IP即可"    mask='255.255.255.255'    dev=lo:1    case $1 in    start)        echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore        echo 1 > /proc/sys/net/ipv4/conf/lo/arp_ignore        echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce        echo 2 > /proc/sys/net/ipv4/conf/lo/arp_announce        ifconfig $dev $vip netmask $mask #broadcast $vip up        #route add -host $vip dev $dev        echo "The RS Server is Ready!"        ;;    stop)        ifconfig $dev down        echo 0 > /proc/sys/net/ipv4/conf/all/arp_ignore        echo 0 > /proc/sys/net/ipv4/conf/lo/arp_ignore        echo 0 > /proc/sys/net/ipv4/conf/all/arp_announce        echo 0 > /proc/sys/net/ipv4/conf/lo/arp_announce        echo "The RS Server is Canceled!"        ;;    *)        echo "Usage: $(basename $0) start|stop"        exit 1        ;;    esac

3，查看lo网卡

[root@centos7-web_server_A ~]# ip a     1: lo: 
    
      mtu 65536 qdisc noqueue state UNKNOWN qlen 1    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00    inet 127.0.0.1/8 scope host lo       valid_lft forever preferred_lft forever    inet 172.18.38.99/32 scope global lo:1       valid_lft forever preferred_lft forever    inet6 ::1/128 scope host        valid_lft forever preferred_lft forever    [root@centos7-web_server_B ~]# ip a     1: lo: 
     
       mtu 65536 qdisc noqueue state UNKNOWN qlen 1    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00    inet 127.0.0.1/8 scope host lo       valid_lft forever preferred_lft forever    inet 172.18.38.99/32 scope global lo:1       valid_lft forever preferred_lft forever    inet6 ::1/128 scope host        valid_lft forever preferred_lft forever
     
    

客户端测试

1，不宕任何服务

[root@centos6 ~]# for i in {1..10};do sleep 0.5;curl 172.18.38.99;done    web_server_B    web_server_A    web_server_B    web_server_A    web_server_B    web_server_A    web_server_B    web_server_A    web_server_B    web_server_A

2，宕掉一台keepalived测试

[root@centos7 lvs_master ~]# systemctl stop keepalived.service    [root@centos6 ~]# for i in {1..10};do sleep 0.5;curl 172.18.38.99;done    web_server_B    web_server_A    web_server_B    web_server_A    web_server_B    web_server_A    web_server_B    web_server_A    web_server_B    web_server_A

测试通过