双web服务器负载均衡配置

  本次实验是为了解决单台的web服务器访问压力过大而进行的，这里用双web服务器加单独的Mysql服务器来实现；平台是RedHat Linux 5.8系统。

 

具体实现方案：    

        

  上图中的web1上将安装：Nginx、DNS、NFS；web2只安装Nginx；Mysql上安装Mysql数据库和PHP。

  当某客户端发送访问请求时，DNS会将请求轮询到web1或web2服务器上，DNS上的算法会计算出该将请求发给哪个服务器响应，基本上是平均的，这样就减小了web服务器的访问压力；

  访问请求到达web服务器后，web服务器会检测客户端请求的是什么内容，如果是静态页面文件，就直接响应客户端；如果是动态的网页内容，就会通过接口送至Mysql服务器上的PHP进行解析，PHP再访问数据库的数据，并将结果返回web服务器，web服务器就响应客户端。

 

步骤：  

  首先每台服务器都要先关闭RedHat的SELinux。

查看SELinux的当前状态
#getenforce
如果是处于'ermissive'，就不用再执行下面的命令了
#setenfoce 0   关闭

配置web1

  1.编译安装Nginx

# yum -y install pcre-devel  解决依赖关系
# groupadd -r nginx
# useradd -r -g nginx -s /bin/false -M nginx
# tar xf nginx-1.2.2.tar.gz
# cd nginx-1.2.2
# ./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/tmp/nginx/client/ \
  --http-proxy-temp-path=/var/tmp/nginx/proxy/ \
  --http-fastcgi-temp-path=/var/tmp/nginx/fcgi/ \
  --http-uwsgi-temp-path=/var/tmp/nginx/uwsgi \
  --http-scgi-temp-path=/var/tmp/nginx/scgi \
  --with-pcre
# make
# maek install

创建SysV脚本，使之支持服务启动命令
# vim /etc/rc.d/init.d/nginx   编辑如下内容

#!/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
添加到服务列表并使开机启动
# chkconfig --add nginx
# chkconfig nginx on

  启动nginx并测试一下是否正常工作。

 

  修改nginx的配置文件

worker_processes  2;
events {
    worker_connections   50000;
}
http {
    include       mime.types;
    default_type  application/octet-stream;
    sendfile      on;
    keepalive_timeout   65;
    server {
         listen       172.16.3.110:80;
         server_name  localhost;
         location / {
              root    html;
              index   index.html index.htm index.php;
         }
         location ~ \.php$ {
              root    html;
              fastcgi_pass   172.16.3.112:9000;
              fastcgi_index  inedx.php;
              fastcgi_param  SCRIPT_FILENAME    /scripts$fastcgi_script_name;
              include        fastcgi_params;
         error_page    500 502 503 504   /50x.html;
         location = /50x.html {
               root    html;
          }
     }

}

  编辑/etc/nginx/fastcgi_params,将内容替换

fastcgi_param  GATEWAY_INTERFACE  CGI/1.1;
fastcgi_param  SERVER_SOFTWARE    nginx;
fastcgi_param  QUERY_STRING       $query_string;
fastcgi_param  REQUEST_METHOD     $request_method;
fastcgi_param  CONTENT_TYPE       $content_type;
fastcgi_param  CONTENT_LENGTH     $content_length;
fastcgi_param  SCRIPT_FILENAME   $document_root$fastcgi_script_name;
fastcgi_param  SCRIPT_NAME        $fastcgi_script_name;
fastcgi_param  REQUEST_URI        $request_uri;
fastcgi_param  DOCUMENT_URI       $document_uri;
fastcgi_param  DOCUMENT_ROOT      $document_root;
fastcgi_param  SERVER_PROTOCOL    $server_protocol;
fastcgi_param  REMOTE_ADDR        $remote_addr;
fastcgi_param  REMOTE_PORT        $remote_port;
fastcgi_param  SERVER_ADDR        $server_addr;
fastcgi_param  SERVER_PORT        $server_port;
fastcgi_param  SERVER_NAME        $server_name;

配置NFS共享

# vim /etc/exports
/etc/nginx/mnt 172.16.0.0/16 (rw,no_root_squash,)

  编译安装DNS

# yum -y install bind97 bind97-devel bind97-libs bind97-utils

  修改主配置文件/etc/named.conf

修改文件中的zone部分
zone "web1.com" IN {
           type master;
           file "web1.com.zone";
           allow-update{ none; };
};

zone "web2.com" IN {
           type master;
           file "web2.com.zone";
           allow-update{ none; };
};

zone "mp.com" IN {
           type master;
           file "mp.com.zone";
           allow-update{ none; };
}

  添加两条A记录

$TTL  600
@      IN  SOA    ns.web1.com.   admin.web1.com.  (
                                   0     ; serial
                                   1D    ; refresh
                                   1H    ; retry
                                   1W    ; expire
                                   3H )  ; minimum
      IN   NS      ns.web.com
ns    IN    A      172.16.3.110
www   IN    A　　　172.16.3.110
www   IN    A      172.16.3.111

2.配置web2

  这里安装Nginx与web1相同，只是蟹盖配置文件时有些不同

worker_processes  2;
events {
    worker_connections   50000;
}
http {
    include       mime.types;
    default_type  application/octet-stream;
    sendfile      on;
    keepalive_timeout   65;
    server {
         listen       172.16.3.111:80;
         server_name  localhost;
         location / {
              root    html;
              index   index.html index.htm index.php;
         }
         location ~ \.php$ {
              root    html;
              fastcgi_pass   172.16.3.112:9000;
              fastcgi_index  inedx.php;
              fastcgi_param  SCRIPT_FILENAME    /scripts$fastcgi_script_name;
              include        fastcgi_params;
         error_page    500 502 503 504   /50x.html;
         location = /50x.html {
               root    html;
          }
     }

}

 

3.配置Mysql服务器

  编译安装Mysql数据库  

  将下载好的Mysql源码包进行编译安装

# tar xf mysql-5.5.24-linux2.6-i686.tar.gz -C /usr/local
# cd /usr/local/
# ln -sv mysql-5.5.24-linux2.6-i686  mysql
# cd mysql
# chown -R mysql:mysql  .
# scripts/mysql_install_db --user=mysql --datadir=/mydata/data
# chown -R root  .

修改配置文件

# cd /usr/local/mysql
# cp support-files/my-large.cnf  /etc/my.cnf   软件提供的样本
修改
thread_concurrency = 2
datadir = /mydata/data

  为Mysql提供服务启动脚本

# cd /usr/local/mysql
# cp support-files/mysql.server  /etc/rc.d/init.d/mysqld
# chkconfig --add mysqld
# chkconfig mysqld on

  这样Mysql就可以启动了，但是因为是编译安装，所以仅仅这样很不符合系统使用规范，我们就把它做的规范些

 输出man手册
# vim /etc/man.config    添加
MANPATH  /usr/local/mysql/man
输出头文件到指定的位置
# ln -sv /usr/local/mysql/include  /usr/include/mysql
输出库文件的路径
# echo '/usr/local/mysql/lib' > /etc/ld.so.conf.d/mysql.conf
设置PATH的环境变量
# vim /etc/profile
PATH=/usr/local/mysql/bin:#PATH

  然后重新载入下：#ldconfig

  编译安装PHP

# tar xf php-5.4.4.tar.bz2
# cd php-5.4.4
#  ./configure --prefix=/usr/local/php4nginx
--with-mysql=/usr/local/mysql --with-openssl --enable-fpm
--enable-sockets --enable-sysvshm
--with-mysqli=/usr/local/mysql/bin/mysql_config
--enable-mbstring --with-freetype-dir --with-jpeg-dir
--with-png-dir --with-zlib-dir --with-libxml-dir=/usr
--enable-xml  --with-mhash --with-mcrypt  --with-config-file-path=/etc
--with-config-file-scan-dir=/etc/php.d --with-bz2 --with-curl
# make # make test # make intall

  为PHP提供配置文件和服务启动脚本

# cp php.ini-production /etc/php.ini
# cp sapi/fpm/init.d.php-fpm  /etc/rc.d/init.d/php-fpm
# chmod +x /etc/rc.d/init.d/php-fpm
# chkconfig --add php-fpm
# chkconfig php-fpm on

  设置php-fpm参数

首先把PHP提供的配置文件样本复制并重命名
# cp /usr/local/php/etc/php-fpm.conf.default /usr/local/php/etc/php-fpm.conf

# vim /usr/local/php/etc/php-fpm.conf
 pm.max_children = 50
 pm.start_servers = 5
 pm.min_spare_servers = 2
 pm.max_spare_servers = 8
 pid = /usr/local/php/var/run/php-fpm.pid
启动并验证
# service php-fpm start
# ps aux | grep php-fpm

  PHP算是配置好了，可是为了系统更给力的工作，给PHP安装xcache加速器吧

# tar xf xcache-2.0.0.tar.gz
# cd xcache-2.0.0
# /usr/local/php/bin/phpize
# ./configure --enable-xcache --with-php-config=/usr/local/php/bin/php-config
# make && make install
安装完成后，会出现一个
Installing shared extensions: ..............的字符串，把冒号后面的复制下备用
编辑php.ini就可以将exache跟php整合到一块了
把xcache提供的样例配置导入php.ini
# mkdir /etc/php.d
# cp /xcache/xcache.ini /etc/php.d
编辑/etc/php.d,找到zend_extension开头行，将复制的字符串粘进去
然后重启php-fpm
# service php-fpm restart

 

 

（对与写博客，也就是对平常知识的总结，这是需要下大功夫的，并且很有必要；也不是说不会总结，只是，像这种写成文章来，还真是不好搞，写着写着就乱了，也看了很多写的好的文章、博客，跟人家一比较还真不好意思拿出来让大家看了；想想这个也只有多练了。不唠叨了，苦练吧！）