[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        daemonfrontend 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-srvbackend 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 514local1.* /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.