带健康状态监测的nginx做反向代理多台服务器实现负载均衡

原理在 nginx让web更精彩那里面基本上已经介绍完了，下面直接开始配置
安装配置第三方模块，实现upstream中对后端http server的健康状态检测：
yum  groupinstall   "Development Libraries" "Development Tools"
yum install  pcre-devel -y
wget http://www.nginx.org/download/nginx-1.0.14.tar.gz

[root@localhost src]#tar xf cep21-healthcheck_nginx_upstreams-16d6ae7.tar.gz
[root@localhost src]# mv cep21-healthcheck_nginx_upstreams-16d6ae7 healthcheck_nginx_upstreams
[root@localhost src]#tar xf nginx-1.0.14.tar.gz
对nginx打补丁
[root@localhost src]#cd nginx-1.0.14
[root@localhost nginx-1.0.14]# patch -p1 < ../healthcheck_nginx_upstreams/nginx.patch
patching file src/http/ngx_http_upstream.c
Hunk #1 succeeded at 4296 (offset 3 lines).
patching file src/http/ngx_http_upstream.h
Hunk #1 succeeded at 110 (offset 1 line).
patching file src/http/ngx_http_upstream_round_robin.c
Hunk #1 succeeded at 5 (offset 1 line).
Hunk #3 succeeded at 36 (offset 1 line).
Hunk #5 succeeded at 390 (offset 1 line).
Hunk #7 succeeded at 497 (offset 1 line).
Hunk #9 succeeded at 633 (offset 1 line).
patching file src/http/ngx_http_upstream_r
而后编译nginx，在执行configure时添加类似下面的选项：
--add-module=/usr/local/src/healthcheck_nginx_upstreams
[root@localhost nginx-1.0.14]# groupadd -r nginx
[root@localhost nginx-1.0.14]# useradd -r -g nginx -s /bin/false -M nginx
[root@localhost nginx-1.0.14]#  ./configure \
   --prefix=/usr \
   --sbin-path=/usr/sbin/nginx \
   --conf-path=/etc/nginx/nginx.conf \
   --error-log-path=/var/log/nginx/error.log \
   --http-log-path=/var/log/nginx/access.log \
   --pid-path=/var/run/nginx/nginx.pid  \
   --lock-path=/var/lock/nginx.lock \
   --user=nginx \
   --group=nginx \
   --with-http_ssl_module \
   --with-http_flv_module \
   --with-http_stub_status_module \
   --with-http_gzip_static_module \
   --http-client-body-temp-path=/var/usr/local/src/nginx/client/ \
   --http-proxy-temp-path=/var/usr/local/src/nginx/proxy/ \
   --http-fastcgi-temp-path=/var/usr/local/src/nginx/fcgi/ \
   --with-pcre \
   --add-module=/usr/local/src/healthcheck_nginx_upstreams/
######./configure 结果如下#####
Configuration summary
  + using system PCRE library
  + using system OpenSSL library
  + md5: using OpenSSL library
  + sha1: using OpenSSL library
  + using system zlib library

  nginx path prefix: "/usr"
  nginx binary file: "/usr/sbin/nginx"
  nginx configuration prefix: "/etc/nginx"
  nginx configuration file: "/etc/nginx/nginx.conf"
  nginx pid file: "/var/run/nginx/nginx.pid"
  nginx error log file: "/var/log/nginx/error.log"
  nginx http access log file: "/var/log/nginx/access.log"
  nginx http client request body temporary files: "/var/usr/local/src/nginx/client/"
  nginx http proxy temporary files: "/var/usr/local/src/nginx/proxy/"
  nginx http fastcgi temporary files: "/var/usr/local/src/nginx/fcgi/"
  nginx http uwsgi temporary files: "uwsgi_temp"
  nginx http scgi temporary files: "scgi_temp"
[root@localhost nginx-1.0.14]# make && make install
[root@localhost nginx-1.0.14]# vim /etc/init.d/nginx
#!/bin/sh
#
# nginx - this script starts and stops the nginx daemon
#
# chkconfig:   - 85 15
# description:  Nginx is an HTTP(S) server, HTTP(S) reverse \
#               proxy and IMAP/POP3 proxy server
# processname: nginx
# config:      /etc/nginx/nginx.conf
# config:      /etc/sysconfig/nginx
# pidfile:     /var/run/nginx.pid
 
# Source function library.
. /etc/rc.d/init.d/functions
 
# Source networking configuration.
. /etc/sysconfig/network
 
# Check that networking is up.
[ "$NETWORKING" = "no" ] && exit 0
 
nginx="/usr/sbin/nginx"
prog=$(basename $nginx)
 
NGINX_CONF_FILE="/etc/nginx/nginx.conf"
 
[ -f /etc/sysconfig/nginx ] && . /etc/sysconfig/nginx
 
lockfile=/var/lock/subsys/nginx
 
make_dirs() {
   # make required directories
   user=`nginx -V 2>&1 | grep "configure arguments:" | sed 's/[^*]*--user=\([^ ]*\).*/\1/g' -`
   options=`$nginx -V 2>&1 | grep 'configure arguments:'`
   for opt in $options; do
       if [ `echo $opt | grep '.*-temp-path'` ]; then
           value=`echo $opt | cut -d "=" -f 2`
           if [ ! -d "$value" ]; then
               # echo "creating" $value
               mkdir -p $value && chown -R $user $value
           fi
       fi
   done
}
 
start() {
    [ -x $nginx ] || exit 5
    [ -f $NGINX_CONF_FILE ] || exit 6
    make_dirs
    echo -n $"Starting $prog: "
    daemon $nginx -c $NGINX_CONF_FILE
    retval=$?
    echo
    [ $retval -eq 0 ] && touch $lockfile
    return $retval
}
 
stop() {
    echo -n $"Stopping $prog: "
    killproc $prog -QUIT
    retval=$?
    echo
    [ $retval -eq 0 ] && rm -f $lockfile
    return $retval
}
 
restart() {
    configtest || return $?
    stop
    sleep 1
    start
}
 
reload() {
    configtest || return $?
    echo -n $"Reloading $prog: "
    killproc $nginx -HUP
    RETVAL=$?
    echo
}
 
force_reload() {
    restart
}
 
configtest() {
  $nginx -t -c $NGINX_CONF_FILE
}
 
rh_status() {
    status $prog
}
 
rh_status_q() {
    rh_status >/dev/null 2>&1
}
 
case "$1" in
    start)
        rh_status_q && exit 0
        $1
        ;;
    stop)
        rh_status_q || exit 0
        $1
        ;;
    restart|configtest)
        $1
        ;;
    reload)
        rh_status_q || exit 7
        $1
        ;;
    force-reload)
        force_reload
        ;;
    status)
        rh_status
        ;;
    condrestart|try-restart)
        rh_status_q || exit 0
            ;;
    *)
        echo $"Usage: $0 {start|stop|status|restart|condrestart|try-restart|reload|force-reload|configtest}"
        exit 2
esac
[root@localhost nginx-1.0.14]# chmod +x /etc/init.d/nginx
[root@localhost nginx-1.0.14]# chkconfig --add nginx
[root@localhost nginx-1.0.14]# service nginx start
Starting nginx:                                            [  OK  ]
[root@localhost nginx-1.0.14]# cd /etc/nginx/
[root@localhost nginx]# mv nginx.conf nginx.conf.bak
[root@localhost nginx]#vim nginx.conf
user  nginx;
worker_processes  2;

#error_log  logs/error.log;
#error_log  logs/error.log  notice;
#error_log  logs/error.log  info;

#pid        logs/nginx.pid;

events {
    worker_connections  1024;
}

http {
    include       mime.types;
    default_type  application/octet-stream;

    #log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
    #                  '$status $body_bytes_sent "$http_referer" '
    #                  '"$http_user_agent" "$http_x_forwarded_for"';

    #access_log  logs/access.log  main;

    sendfile        on;
    #tcp_nopush     on;

    #keepalive_timeout  0;
    keepalive_timeout  65;

    #gzip  on;
    upstream www.gabylinux.com {
        server  192.168.1.117 weight=5;
        server  192.168.1.118 max_fails=3 fail_timeout=30s;
        server  192.168.1.189:8080;
        }
    server {
        listen 80;
        server_name www.gabylinux.com;
        access_log /var/log/www.gabylinux.com/access.log;
        error_log /var/log/www.gabylinux.com/error.log debug;
        #set your default location
        location / {
                proxy_set_header   Host             $host;
                proxy_set_header   X-Real-IP        $remote_addr;
                proxy_pass http://www.gabylinux.com;
        }
     }

}
[root@localhost nginx]# mkdir -p /var/log/www.gabylinux.com/
[root@localhost nginx]# service nginx reload
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful
Reloading nginx:                                           [  OK  ]

这时候我们用ie浏览器访问192.168.1.189，能够发现访问到不同realserver上，如果其中一台realserver宕机的话，nginx会自动把他踢掉。
生产环境中可以优化上面参数，以提高性能。