编译安装HAProxy

① 要求最低lua版本为5.3的环境

yum install -y lua;lua -v #要求HAProxy最低lua版本为5.3
yum -y install gcc make openssl-devel pcre-devel systemd-devel

② 下载源码并编译安装

wget https://www.haproxy.org/download/2.4/src/haproxy-2.4.9.tar.gz
tar xvf haproxy-2.4.9.tar.gz -C /usr/local/src
cd /usr/local/src/haproxy-2.4.9
make ARCH=x86_64 TARGET=linux-glibc USE_PCRE=1 USE_OPENSSL=1 USE_ZLIB=1 USE_SYSTEMD=1 #USE_LUA=1 LUA_INC=/usr/local/src/lua-5.3.5/src/ LUA_LIB=/usr/local/src/lua-5.3.5/src/
make install PREFIX=/apps/haproxy
ln -s /apps/haproxy/sbin/haproxy /usr/sbin/

③ 准备service启动文件

vim /usr/lib/systemd/system/haproxy.service
[Unit]
Description=HAProxy Load Balancer
After=syslog.target network.target
[Service]
ExecStartPre=/usr/sbin/haproxy -f /etc/haproxy/haproxy.cfg  -c -q
ExecStart=/usr/sbin/haproxy -Ws -f /etc/haproxy/haproxy.cfg -p /var/lib/haproxy/haproxy.pid
ExecReload=/bin/kill -USR2 $MAINPID
LimitNOFILE=100000
[Install]
WantedBy=multi-user.target

④ 创建配置文件

vim /etc/haproxy/haproxy.cfg
global
    maxconn 100000
    chroot /apps/haproxy
    stats socket /var/lib/haproxy/haproxy.sock mode 600 level admin
    #uid 99
    #gid 99
    user haproxy
    group haproxy
    daemon
    #nbproc 4
    #cpu-map 1 0
    #cpu-map 2 1
    #cpu-map 3 2
    #cpu-map 4 3
    pidfile /var/lib/haproxy/haproxy.pid
    log 127.0.0.1 local2 info
defaults
   option http-keep-alive
   option forwardfor
   maxconn 100000
   mode http
   timeout connect 300000ms
   timeout client 300000ms
   timeout server 300000ms
listen stats
   mode http
   bind 0.0.0.0:9999
   stats enable
   log global
   stats uri     /haproxy-status
   stats auth   haadmin:123456
listen web_port
   bind 10.0.0.28:80
   mode http
   log global
   server web1  10.0.0.7:80 check inter 3000 fall 2 rise 5
   server web2  10.0.0.17:80 check inter 3000 fall 2 rise 5
   redirect prefix http://www.baidu.com/  #重定向
   server backup  127.0.0.1:80 backup

⑤ 启动

mkdir /var/lib/haproxy         #准备socket文件目录
useradd -r -s /sbin/nologin -d /var/lib/haproxy haproxy            #设置用户和目录权限
systemctl enable --now haproxy
web访问：http://10.0.0.28:9999/haproxy-status

日志配置

失败嘞！

HAProxy配置，在global配置项定义
log 127.0.0.1 local{1-7} info #基于syslog记录日志到指定设备
log 10.0.0.8 local2 info
listen web_port
 bind 127.0.0.1:80
 mode http
 log global #开启当前web_port的日志功能，默认不记录日志
 server web1  127.0.0.1:8080 check inter 3000 fall 2 rise 5
systemctl restart haproxy

Rsyslog配置
vim /etc/rsyslog.conf 
$ModLoad imudp
$UDPServerRun 514
......
local3.*   /var/log/haproxy.log
systemctl restart rsyslog

配置 frontend+backend

frontend WEB_PORT_80
   bind 10.0.0.28:80
   mode http
   use_backend web_prot_http_nodes
backend web_prot_http_nodes
   mode http
   option forwardfor
   server 10.0.0.7 10.0.0.7:80   check inter 3000 fall 3 rise 5  
   server 10.0.0.17 10.0.0.17:80   check inter 3000 fall 3 rise 5
   redirect prefix http://www.baidu.com/  #重定向

使用子配置

子配置文件的文件后缀必须为.cfg

mkdir /etc/haproxy/conf.d/
vim /lib/systemd/system/haproxy.service
[Unit]
Description=HAProxy Load Balancer
After=syslog.target network.target
[Service]    #修改下面两行
ExecStartPre=/usr/sbin/haproxy -f /etc/haproxy/haproxy.cfg -f /etc/haproxy/conf.d/ -c -q
ExecStart=/usr/sbin/haproxy -Ws -f /etc/haproxy/haproxy.cfg -f /etc/haproxy/conf.d/ -p /var/lib/haproxy/haproxy.pid
ExecReload=/bin/kill -USR2 $MAINPID
[Install]
WantedBy=multi-user.target
创建子配置文件，注意：必须为cfg后缀非.开头的配置文件
vim /etc/haproxy/conf.d/test.cfg
systemctl daemon-reload
systemctl restart haproxy

调度算法——socat

echo "help"|socat stdio /var/lib/haproxy/haproxy.sock
echo "get weight web_port/web1"|socat stdio /var/lib/haproxy/haproxy.sock
echo "set weight web_port/web1 0"|socat stdio /var/lib/haproxy/haproxy.sock （改权重为0，实现优雅下线）

静态（static-rr, first）

balance static-rr
balance first

动态（roundrobin, leastconn, random）

balance roundrobin
balance leastconn
balance random

其他(source,uri,url_param,hdr,rdp-cookie)

source (map-based, consistent)

 balance source
 hash-type map-based 
 #不支持动态调整权重值,只能动态上线和下线

 balance source
 hash-type consistent
 #一致性哈希，当服务器的总权重发生变化时，对调度结果影响是局部的，不会引起大的变动;该hash算法是动态的

uri

 balance uri
 hash-type consistent

url_param

balance url_param userid
hash-type consistent

hdr

 balance hdr(User-Agent)
 hash-type consistent

rdp-cookie(基于windows)

 balance rdp-cookie
 hash-type consistent
基于iptables实现RDP协议转发,必须开启ip转发功能： net.ipv4.ip_forward = 1

#客户端和Windows在不同网段需要下面命令,注意后端服务器需要将iptables主机配置为网关
iptables -t nat -A PREROUTING -d 172.16.0.100 -p tcp --dport 3389 -j DNAT --to-destination 10.0.0.200:3389

#客户端和Windows在同一网段需要再执行下面命令
iptables -t nat -A PREROUTING -d 10.0.0.8 -p tcp --dport 3389 -j DNAT --to-destination 10.0.0.200:3389
iptables -t nat -A POSTROUTING -s 10.0.0.0/24 -j SNAT --to-source 10.0.0.8

报错

报错1：HAProxy后启动报错“cannot bind UNIX socket [/var/run/haproxy/admin.sock]”
解决：
mkdir  /var/run/haproxy/
touch /var/run/haproxy/admin.sock