centos7下通过LVS的DR模式实现负载均衡访问

一、两台服务器作为real server ，一台作为director

director:172.28.18.69 vip:172.28.18.70

real server1:172.28.18.71

real server2:172.28.18.78

二、两台real server上安装nginx

配置nginx yum源

[root@localhost ~]# vim /etc/yum.repos.d/nginx.repo
 
[nginx]
name=nginx repo
baseurl=http://nginx.org/packages/centos/7/$basearch/
gpgcheck=
enabled=

安装

[root@localhost ~]# yum install -y nginx

查看

[root@localhost ~]# whereis nginx
nginx: /usr/sbin/nginx /usr/lib64/nginx /etc/nginx /usr/share/nginx /usr/share/man/man8/nginx..gz
[root@localhost ~]#

配置文件

查看默认根目录页面地址

[root@localhost ~]# vim /etc/nginx/conf.d/default.conf 
 
server {
    listen       ;
    server_name  localhost;
 
    #charset koi8-r;
    #access_log  /var/log/nginx/host.access.log  main;
 
    location / {
        root   /usr/share/nginx/html;
        index  index.html index.htm;
    }

编辑/usr/share/nginx/html/index.html

加上本机IP地址，在测试负载均衡的时候，才知道分发到了哪台real server上

[root@localhost ~]# vim /usr/share/nginx/html/index.html 
 
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
    body {
        width: 35em;
        margin:  auto;
        font-family: Tahoma, Verdana, Arial, sans-serif;
    }
</style>
</head>
<body>
<h1>Welcome to nginx!-</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>
 
<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>
 
<p><em>Thank you for using nginx.</em></p>
</body>
</html>

保存、退出

启动nginx

[root@localhost conf.d]# nginx -c /etc/nginx/nginx.conf

在浏览器查看

可以显示IP了，同样172.28.18.78的服务器也安装和配置nginx

三、在172.28.18.69上安装ipvsadm

[root@localhost mysql-5.7.]# yum install -y ipvsadm
已加载插件：fastestmirror
Loading mirror speeds from cached hostfile
 * base: mirrors.tuna.tsinghua.edu.cn
 * extras: mirrors.huaweicloud.com
 * updates: mirrors.tuna.tsinghua.edu.cn
base                                                                                | 3.6 kB  ::
extras                                                                              | 3.4 kB  ::
updates                                                                             | 3.4 kB  ::
正在解决依赖关系
--> 正在检查事务
---> 软件包 ipvsadm.x86_64.0.1.-.el7 将被 安装
--> 解决依赖关系完成
 
依赖关系解决
 
===========================================================================================================
 Package                  架构                    版本                         源                     大小
===========================================================================================================
正在安装:
 ipvsadm                  x86_64                  1.27-.el7                   base                    k
 
事务概要
===========================================================================================================
安装   软件包
 
总下载量： k
安装大小： k
Downloading packages:
ipvsadm-1.27-.el7.x86_64.rpm                                                       |   kB  ::
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
警告：RPM 数据库已被非 yum 程序修改。
** 发现  个已存在的 RPM 数据库问题， 'yum check' 输出如下：
:postfix-2.10.-.el7.x86_64 有缺少的需求 libmysqlclient.so.()(64bit)
:postfix-2.10.-.el7.x86_64 有缺少的需求 libmysqlclient.so.(libmysqlclient_18)(64bit)
  正在安装    : ipvsadm-1.27-.el7.x86_64                                                              /
  验证中      : ipvsadm-1.27-.el7.x86_64                                                              / 
 
已安装:
  ipvsadm.x86_64 :1.27-.el7                                                                              
 
完毕！

四、配置虚拟服务器

[root@director ~]# ipvsadm -A -t 172.28.18.70: -s rr

增加一个虚拟服务器 172.28.18.69, -A:增加一个虚拟服务器 -t:tcp协议 -s：分发算法 rr 轮询

五、增加后端实际服务器

[root@director ~]# ipvsadm -a -t 172.28.18.70: -r 172.28.18.71: -g -w 1
[root@director ~]# ipvsadm -a -t 172.28.18.70: -r 172.28.18.78: -g -w 1

-a :增加后端服务器 -t:对应的虚拟服务器IP -r :对应的后端服务器IP -g: DR模式 -w:权重

六、查看配置规则

[root@director home]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 172.28.18.70:80 rr
-> 172.28.18.71:80 Route 1 0 0
-> 172.28.18.78:80 Route 1 0 0

七、设置director分发器的虚拟IP到设备em1:0

[root@director home]# ip addr add 172.28.18.70 dev em1:
[root@director home]# ip a
: lo: <LOOPBACK,UP,LOWER_UP> mtu  qdisc noqueue state UNKNOWN group default qlen
    link/loopback ::::: brd :::::
    inet 127.0.0.1/ scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::/ scope host
       valid_lft forever preferred_lft forever
: em1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu  qdisc mq state UP group default qlen
    link/ether :fe:b5:dc:2c: brd ff:ff:ff:ff:ff:ff
    inet 172.28.18.69/ brd 172.28.18.79 scope global noprefixroute em1
       valid_lft forever preferred_lft forever
    inet 172.28.18.70/ scope global em1
       valid_lft forever preferred_lft forever
    inet6 fe80::b3e8:e3b2::a2ed/ scope link noprefixroute
       valid_lft forever preferred_lft forever
: em2: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu  qdisc mq state DOWN group default qlen
    link/ether :fe:b5:dc:2c: brd ff:ff:ff:ff:ff:ff
: em3: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu  qdisc mq state DOWN group default qlen
    link/ether :fe:b5:dc:2c:7b brd ff:ff:ff:ff:ff:ff
: em4: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu  qdisc mq state DOWN group default qlen
    link/ether :fe:b5:dc:2c:7d brd ff:ff:ff:ff:ff:ff

ip -a 查看，172.28.18.70已经绑定到em1:0上了

此时，在其他机器上测试curl 172.28.18.70，还是不通，是因为在后端服务器上还需要设置虚拟IP绑定到回环接口上

八、绑定虚拟IP到后端服务器的回环接口上

[root@server- html]# ip addr add 172.28.18.70 dev lo:

九、在其他服务器上测试172.28.18.70

[root@zabbix_server ~]# curl 172.28.18.70
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
width: 35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
</head>
<body>
<h1>Welcome to nginx!-71</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>

分发到71上

[root@zabbix_server ~]# curl 172.28.18.70
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
width: 35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
</head>
<body>
<h1>Welcome to nginx!-78</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>

再次请求，分发到78上。至此lvsDR模式负载均衡配置完成。