[负载均衡]haproxy

这东西非常强大..配置语法跟之前tengine的类似.

1.健康检查的例子:

主要是使用check关键字:

#
# demo config for Proxy mode
#

global
        maxconn         20000
#	ulimit-n	20000
	# ulimit-n	16384
        log             127.0.0.1 local0
	# log /tmp/haproxy.log
        uid             200
        gid             200
#        chroot          /var/empty
	nbproc		4
        daemon

frontend test-proxy
	bind		0.0.0.0:81
	# bind		192.168.200.10:8080
        mode            http
        log             global
        option          httplog
        option          dontlognull
        option          nolinger
        option          http_proxy
        maxconn         8000
        timeout client  30s

	# layer3: Valid users
#	acl allow_host src 192.168.200.150/32
#	http-request deny if !allow_host

	# layer7: prevent private network relaying
#	acl forbidden_dst url_ip 192.168.0.0/24
#	acl forbidden_dst url_ip 172.16.0.0/12
#	acl forbidden_dst url_ip 10.0.0.0/8
#	http-request deny if forbidden_dst

	default_backend test-proxy-srv


backend test-proxy-srv
	mode            http
	timeout connect 5s
	timeout server  5s
	retries         2
#	option          nolinger
	option          http_proxy

	# layer7: Only GET method is valid
	acl valid_method        method GET
	http-request deny if !valid_method

	# layer7: protect bad reply
	# http-response deny if { res.hdr(content-type) audio/mp3 }

	balance roundrobin  #负载均衡的方式,roundrobin平均方式
#	cookie SERVERID     #允许插入serverid到cookie中,serverid后面可以定义

#心跳检测的URL,HTTP/1.1¥r¥nHost:XXXX,指定了心跳检测HTTP的版本,XXX为检测时请求
#服务器的request中的域名是什么,这个在应用的检测URL对应的功能有对域名依赖的话需要设置
	option httpchk GET / HTTP/1.0

  #服务器定义,cookie 1表示serverid为1,check inter 1500 是检测心跳频率
  #rise 3是3次正确认为服务器可用,fall 3是3次失败认为服务器不可用,weight代表权重
	server mms1 127.0.0.1:6000 cookie 1 check inter 3000 rise 3 fall 3 weight 1
	server mms2 127.0.0.1:6001 cookie 2 check inter 3000 rise 3 fall 3 weight 2

关于haproxy其实还是不太理解，可以从简单的着手。

2.配置一个简单的本地代理

可以写成这样，一个frontend+一个backend:

# Simple configuration for an HTTP proxy listening on port 80 on all
  # interfaces and forwarding requests to a single backend "servers" with a
  # single server "server1" listening on 127.0.0.1:8000
  global
      daemon
      maxconn 256

  defaults
      mode http
      timeout connect 5000ms
      timeout client 50000ms
      timeout server 50000ms

  frontend http-in
      bind *:81
      default_backend servers

  backend servers
      server server1 127.0.0.1:80 maxconn 32

也可以写成单独的listen:

# The same configuration defined with a single listen block. Shorter but
   # less expressive, especially in HTTP mode.
   global
       daemon
       maxconn 256

   defaults
       mode http
       timeout connect 5000ms
       timeout client 50000ms
       timeout server 50000ms

   listen http-in
       bind *:81
       server server1 127.0.0.1:80 maxconn 32

3.日志记录

这里还缺了一个很关键的日志记录，日志需要和syslog软件相结合。
需要配置一下rsyslog:

$ModLoad imudp
$UDPServerRun 514
local1.* /var/log/haproxy.log

然后在代码中配置相关内容即可:

# Simple configuration for an HTTP proxy listening on port 80 on all
  # interfaces and forwarding requests to a single backend "servers" with a
  # single server "server1" listening on 127.0.0.1:8000
  global
      daemon
      maxconn 256
log 127.0.0.1 local1

  defaults
log global
      mode http
      timeout connect 5000ms
      timeout client 50000ms
      timeout server 50000ms
option httplog

  frontend http-in
      bind *:81
      default_backend servers

  backend servers
      server server1 127.0.0.1:80 maxconn 32

4.配置statistics

listen stats
    bind *:82
    mode http
    stats enable
    stats hide-version
    stats realm Haproxy\ Statistics
    stats uri /
    stats auth admin:Qq123456

haproxy提供一个很方便的monitor界面,比nginx_status好看多了.内容也丰富很多.很直观.