HAProxy提供高可用性、负载均衡以及基于TCP和HTTP的应用代理，支持虚拟主机，它是免费、快速并且可靠的一种负载均衡解决方案。适合处理高负载站点的七层数据请求。类似的代理服务可以屏蔽内部真实服务器，防止内部服务器遭受攻击。
软件：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。
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
——————————————————————————————————————————
ha-proxy概述
ha-proxy是一款高性能的负载均衡软件。因为其专注于负载均衡这一些事情，因此与nginx比起来在负载均衡这件事情上做更好，更专业。
ha-proxy的特点：
ha-proxy 作为目前流行的负载均衡软件，必须有其出色的一面。下面介绍一下ha-proxy负载均衡软件的优点:
1.支持tcp / http 两种协议层的负载均衡，使得其负载均衡功能非常丰富。
2.支持8种左右的负载均衡算法支持会话保持，尤其是在http模式时，有许多非常实在的负载均衡算法，适用各种需求。
3.性能非常优秀，单进程处理模式（和Nginx类似）让其性能卓越。
4.拥有一个功能出色的监控页面，实时了解系统的当前状况。
5.功能强大的ACL支持，给用户极大的方便。
6.支持原生SSL,同时支持客户端和服务器的SSL.
7.并发连接40000-50000个，单位时间处理最大请求20000个，最大数据处理10Gbps.
8.支持虚拟主机
haproxy算法：
1.roundrobin—基于权重进行轮询,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.
1、Haproxy 实现七层负载
Keepalived + Haproxy
=================================================================================
/etc/haproxy/haproxy.cfg
global //关于进程的全局参数
log 127.0.0.1 local2 info #日志服务器
pidfile /var/run/haproxy.pid #pid文件
maxconn 4000 #最大连接数
user haproxy #用户
group haproxy #组
daemon #守护进程方式后台运行
nbproc 1 #工作进程数量 cpu内核是几就写几
defaults 段用于为其它配置段提供默认参数
listen是frontend和backend的结合体
frontend 虚拟服务VIrtual Server
backend 真实服务器Real Server
Keepalived + Haproxy
=================================================================================
拓扑结构
[vip: 192.168.246.17]
[LB1 Haproxy] [LB2 Haproxy]
192.168.246.169 192.168.246.161
[httpd] [httpd]
192.168.246.162 192.168.246.163
一、Haproxy实施步骤
1. 准备工作（集群中所有主机）
[root@ha-proxy-master ~]# cat /etc/hosts
127.0.0.1 localhost
192.168.246.169 ha-proxy-master
192.168.246.161 ha-proxy-slave
192.168.246.162 test-nginx1
192.168.246.163 test-nginx2
2. RS配置
配置好网站服务器，测试所有RS,所有机器安装nginx
[root@test-nginx1 ~]# yum install -y nginx
[root@test-nginx1 ~]# systemctl start nginx
[root@test-nginx1 ~]# echo “test-nginx1” >> /usr/share/nginx/html/index.html
# 所有nginx服务器按顺序输入编号，方便区分。
3. 调度器配置Haproxy（主/备）都执行
[root@ha-proxy-master ~]# yum -y install haproxy
[root@ha-proxy-master ~]# cp -rf /etc/haproxy/haproxy.cfg{,.bak}
[root@ha-proxy-master ~]# sed -i -r ‘/^[ ]*#/d;/^$/d’ /etc/haproxy/haproxy.cfg
[root@ha-proxy-master ~]# vim /etc/haproxy/haproxy.cfg
global
log 127.0.0.1 local2 info
pidfile /var/run/haproxy.pid
maxconn 4000 #优先级低
user haproxy
group haproxy
daemon #以后台形式运行ha-proxy
nbproc 1#工作进程数量 cpu内核是几就写几
defaults
mode http #工作模式 http ,tcp 是 4 层,http是 7 层
log global
retries 3 #健康检查。3次连接失败就认为服务器不可用，主要通过后面的check检查
option redispatch #服务不可用后重定向到其他健康服务器。
maxconn 4000 #优先级中
contimeout 5000 #ha服务器与后端服务器连接超时时间，单位毫秒ms
clitimeout 50000 #客户端超时
srvtimeout 50000 #后端服务器超时
listen stats
bind*:81
stats enable
stats uri /haproxy #使用浏览器访问 http://192.168.246.169/haproxy,可以看到服务器状态
stats auth qianfeng:123 #用户认证，客户端使用elinks浏览器的时候不生效
frontend web
mode http
bind *:80 #监听哪个ip和什么端口
option httplog #日志类别 http 日志格式
acl html url_reg -i .html$ #1.访问控制列表名称html。规则要求访问以html结尾的url
use_backend httpservers if html #2.如果满足acl html规则，则推送给后端服务器httpservers
default_backend httpservers #默认使用的服务器组
backend httpservers #名字要与上面的名字必须一样
balance roundrobin #负载均衡的方式
server http1 192.168.246.162:80 maxconn 2000 weight 1 check inter 1s rise 2 fall 2
server http2 192.168.246.163:80 maxconn 2000 weight 1 check inter 1s rise 2 fall 2
将配置文件拷贝到slave服务器
[root@ha-proxy-master ~]# scp /etc/haproxy/haproxy.cfg 192.168.246.161:/etc/haproxy/
两台机器启动设置开机启动
[root@ha-proxy-master ~]# systemctl start haproxy
[root@ha-proxy-master ~]# systemctl enable haproxy
#check inter 2000 检测心跳频率
#rise 2 2 次正确认为服务器可用
#fall 2 2 次失败认为服务器不可用
4.测试主/备(浏览器访问)
主:
备:
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
========================================================
2.测试访问
通过访问haparoxy的ip地址访问到后端服务器
# curl http://192.168.246.169
如果出现bind失败的报错，执行下列命令
setsebool -P haproxy_connect_any=1
二、Keepalived实现调度器HA
注：主/备调度器均能够实现正常调度
1. 主/备调度器安装软件
[root@ha-proxy-master ~]# yum install -y keepalived
[root@ha-proxy-slave ~]# yum install -y keepalived
[root@ha-proxy-master ~]# cp /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak
[root@ha-proxy-master ~]# 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 {
192.168.246.17/24
}
}
[root@ha-proxy-slave ~]# cp /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak
[root@ha-proxy-slave ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
router_id directory2
}
vrrp_instance VI_1 {
state BACKUP
interface ens33
virtual_router_id 80
priority 50
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.246.17/24
}
}
3. 启动KeepAlived（主备均启动）
[root@ha-proxy-master ~]# chkconfig keepalived on
[root@ha-proxy-master ~]# service keepalived start
[root@ha-proxy-master ~]# ip a
4. 扩展对调度器Haproxy健康检查（可选）
思路：一台机器做
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
a. script
[root@ha-proxy-master ~]# cat /etc/keepalived/check_haproxy_status.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@ha-proxy-master ~]# chmod a+x /etc/keepalived/check_haproxy_status.sh
b. keepalived使用script
[root@ha-proxy-master keepalived]# vim keepalived.conf
! Configuration File for keepalived
global_defs {
router_id director1
}
vrrp_script check_haproxy {
script “/etc/keepalived/check_haproxy_status.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 {
192.168.246.17/24
}
track_script {
check_haproxy
}
}
[root@ha-proxy-slave keepalived]# vim keepalived.conf
! Configuration File for keepalived
global_defs {
router_id directory2
}
vrrp_script check_haproxy {
script “/etc/keepalived/check_haproxy_status.sh”
interval 5
}
vrrp_instance VI_1 {
state BACKUP
interface ens33
virtual_router_id 80
priority 50
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.246.17/24
}
track_script {
check_haproxy
}
}
[root@ha-proxy-master keepalived]# systemctl restart keepalived
[root@ha-proxy-slave keepalived]# systemctl restart keepalived
注：必须先启动haproxy，再启动keepalived
两台机器都配置haproxy的日志:需要打开注释并添加
[root@ha-proxy-master ~]# vim /etc/rsyslog.conf
# Provides UDP syslog reception #由于haproxy的日志是用udp传输的,所以要启用rsyslog的udp监听
$ModLoad imudp
$UDPServerRun 514
找到 #### RULES #### 下面添加
local2.info /var/log/haproxy.log
[root@ha-proxy-master ~]# systemctl restart rsyslog
[root@ha-proxy-master ~]# systemctl restart haproxy
[root@ha-proxy-master ~]# tail -f /var/log/haproxy.log
2019-07-13T23:11:35+08:00 localhost haproxy[906]: Connect from 192.168.246.1:56866 to 192.168.246.17:80 (web/HTTP)
2019-07-13T23:11:35+08:00 localhost haproxy[906]: Connect from 192.168.246.1:56867 to 192.168.246.17:80 (web/HTTP)
2019-07-13T23:13:39+08:00 localhost haproxy[906]: Connect from 192.168.246.1:56889 to 192.168.246.17:80 (stats/HTTP)
2019-07-13T23:13:39+08:00 localhost haproxy[906]: Connect from 192.168.246.1:56890 to 192.168.246.17:80 (web/HTTP)
2019-07-13T23:14:07+08:00 localhost haproxy[906]: Connect from 192.168.246.1:56895 to 192.168.246.17:80 (web/HTTP)
2019-07-13T23:14:07+08:00 localhost haproxy[906]: Connect from 192.168.246.1:56896 to 192.168.246.17:80 (stats/HTTP)
四层代理mysql
准备两台机器，关闭防火墙和selinux。
1.两台机器部署mysql并制作互为主从—-略
2.安装haproxy制作代理
[root@haproxy-server ~]# yum -y install haproxy
[root@haproxy-server ~]# cp -rf /etc/haproxy/haproxy.cfg{,.bak}
[root@haproxy-server ~]# sed -i -r ‘/^[ ]*#/d;/^$/d’ /etc/haproxy/haproxy.cfg
[root@haproxy-server ~]# vim /etc/haproxy/haproxy.cfg
global
log 127.0.0.1 local2
pidfile /var/run/haproxy.pid
maxconn 4000
user haproxy
group haproxy
daemon
nbproc 1
defaults
mode http
log global
option redispatch
retries 3
maxconn 3000
contimeout 5000
clitimeout 50000
srvtimeout 50000
listen stats
bind*:81
stats enable
stats uri /haproxy
stats auth qianfeng:123
listen mysql
bind *:3307
mode tcp
balance roundrobin
server mysql1 192.168.198.149:3306 weight 1 check inter 1s rise 2 fall 2
server mysql2 192.168.198.150:3306 weight 1 check inter 1s rise 2 fall 2
[root@haproxy-server ~]# systemctl start haproxy
[root@haproxy-server ~]# netstat -lntp | grep 3307
tcp 0 0 0.0.0.0:33070.0.0.0:* LISTEN 11866/haproxy
3.验证：
[root@haproxy-server ~]# mysql -uroot -p’QianFeng@123!’ -P 3307
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or g.
Your MySQL connection id is 6
Server version: 5.7.31-log MySQL Community Server (GPL)
Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type ‘help;’ or ‘h’ for help. Type ‘c’ to clear the current input statement.
mysql> show databases;
+——————–+
| Database |
+——————–+
| information_schema |
| mysql |
| performance_schema |
| sys |
+——————–+
4 rows in set (0.00 sec)
mysql>
来源：千锋JAVA开发学院
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