目录

Haproxy概述

haproxy算法：

Haproxy实现七层负载

①部署nginx-server测试页面

②(主/备)部署负载均衡器

 ③部署keepalived高可用

 ④增加对haproxy健康检查

⑤测试

---

Haproxy概述

haproxy---主要是做负载均衡的7层，也可以做4层负载均衡
apache也可以做7层负载均衡，但是很麻烦。实际工作中没有人用。
负载均衡是通过OSI协议对应的
7层负载均衡：用的7层http协议，
4层负载均衡：用的是tcp协议加端口号做的负载均衡

haproxy算法：

1.roundrobin
基于权重进行轮询,在服务器的处理时间保持均匀分布时,这是最平衡,最公平的算法.此算法是动态的,这表示其权重可以在运行时进行调整.不过在设计上,每个后端服务器仅能最多接受4128个连接
2.static-rr
基于权重进行轮询,与roundrobin类似,但是为静态方法,在运行时调整其服务器权重不会生效.不过,其在后端服务器连接数上没有限制
3.leastconn
新的连接请求被派发至具有最少连接数目的后端服务器.

Haproxy实现七层负载

keepalived+haproxy

192.168.134.165  master

192.168.134.166 slave

192.168.134.163  nginx-server

192.168.134.164 nginx-server

192.168.134.160   VIP（虚拟IP）

①部署nginx-server测试页面

两台nginx都部署方便测试

[root@server03 ~]# yum -y install nginx
[root@server03 ~]# systemctl  start nginx
[root@server03 ~]# echo "webserver01..." > /usr/share/nginx/html/index.html 

[root@server04 ~]# yum -y install nginx
[root@server04 ~]# systemctl  start nginx
[root@server04 ~]# echo "webserver02..." > /usr/share/nginx/html/index.html

②(主/备)部署负载均衡器

[root@server01 ~]# yum -y install haproxy
[root@server01 ~]# vim /etc/haproxy/haproxy.cfg
global
    log         127.0.0.1 local2 info
    pidfile     /var/run/haproxy.pid
    maxconn     4000
    user        haproxy
    group       haproxy
    daemon
    nbproc 1
defaults
    mode                    http
    log                     global
    retries                 3
    option                  redispatch
    maxconn                 4000
    contimeout              5000
    clitimeout              50000
    srvtimeout              50000
listen stats
    bind                        *:81
    stats                       enable
    stats uri                   /haproxy
    stats auth                  aren:123
frontend  web
    mode                        http
    bind                            *:80
    option                  httplog
    acl html url_reg  -i  \.html$
    use_backend httpservers if  html
    default_backend    httpservers
backend httpservers
    balance     roundrobin
    server  http1 192.168.134.163:80 maxconn 2000 weight 1  check inter 1s rise 2 fall 2
    server  http2 192.168.134.164:80 maxconn 2000 weight 1  check inter 1s rise 2 fall 2

[root@server01 ~]# systemctl  start haproxy

浏览器访问haproxy监控

master:

slave:

页面主要参数解释
Queue
Cur: current queued requests //当前的队列请求数量
Max：max queued requests     //最大的队列请求数量
Limit：           //队列限制数量

Errors
Req：request errors             //错误请求
Conn：connection errors          //错误的连接

Server列表：
Status:状态，包括up(后端机活动)和down(后端机挂掉)两种状态
LastChk:    持续检查后端服务器的时间
Wght: (weight) : 权重

 ③部署keepalived高可用

注意：master和slave的优先级不一样，但虚拟路由id(virtual_router_id)保持一致；并且slave配置 nopreempt（不抢占资源）

master：

[root@server01 ~]# yum -y install keepalived
[root@server01 ~]# vim /etc/keepalived/keepalived.conf 
! Configuration File for keepalived

global_defs {
   router_id director1
}
vrrp_instance VI_1 {
    state MASTER
    interface ens33
    virtual_router_id 80
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.134.160/24
    }
}

[root@server01 ~]# systemctl  start keepalived

slaver：

[root@localhost ~]# yum -y install keepalived
[root@localhost ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
   router_id directory2
}
vrrp_instance VI_1 {
    state BACKUP
    interface ens33
    nopreempt
    virtual_router_id 80
    priority 50
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.134.160/24
    }
}
[root@localhost ~]# systemctl  start keepalived

查看IP

 ④增加对haproxy健康检查

两台机器都做，让Keepalived以一定时间间隔执行一个外部脚本，脚本的功能是当Haproxy失败，则关闭本机的Keepalived。

[root@server01 ~]# vim /etc/keepalived/check.sh
#!/bin/bash 
  /usr/bin/curl -I http://localhost &>/dev/null
if [ $? -ne 0 ];then
#       /etc/init.d/keepalived stop
        systemctl stop keepalived
fi
[root@server01 ~]# chmod a+x /etc/keepalived/check.sh

在keepalived增加健康检查配置vrrp_script check_haproxy并且用 track_script调用。

! Configuration File for keepalived

global_defs {
   router_id director1
}
vrrp_script check_haproxy {
   script "/etc/keepalived/check.sh"
   interval 5
}
vrrp_instance VI_1 {
    state MASTER
    interface ens33
    virtual_router_id 80
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.134.160/24
    }
 track_script {
        check_haproxy
    }
}

重启keepalived

[root@server01 ~]# systemctl  restart keepalived

⑤测试

关闭master的haproxy服务可以发现master的keepalived服务也关闭，此时master上的VIP转移到slave上

• 关闭master的服务并查看VIP

• 查看slave的IP可以发现VIP跳转至此。

• 在web界面查看服务是否正常

第一次刷新

第二次刷新