Nginx + varnish 构建高可用CDN节点集群

一、        环境描述

Linux server A  (CentOS release 5.8 Final)  实IP:192.168.4.97  虚IP:192.168.4.96
Linux server B  (CentOS release 5.8 Final)  实IP:192.168.4.99  虚IP:192.168.4.98

域名环境(DNS轮询解析到虚IP):
server.osapub.com 192.168.4.96
server.osapub.com 192.168.4.98

二、        简单架构示意图

描述:前端两台NGINX做DNS轮询,通过虚IP漂移+HA监控脚本相结合,实现前端两台NGINX高可用,利用NGINX反向代理功能对后端varnish实现高可用集群。

三、软件环境搭建
3.1 编译安装nginx

#!/bin/bash
####nginx 环境安装脚本,注意环境不同可能导致脚本运行出错,如果环境不同建议手工一条一条执行指令。
 
#创建工作目录
mkdir -p /dist/{dist,src}
cd /dist/dist
 
#下载安装包
wget http://bbs.osapub.com/down/google-perftools-1.8.3.tar.gz &> /dev/null
wget http://bbs.osapub.com/down/libunwind-0.99.tar.gz &> /dev/null
wget http://bbs.osapub.com/down/pcre-8.01.tar.gz &> /dev/null
wget http://bbs.osapub.com/down/nginx-1.0.5.tar.gz &> /dev/null
 
#------------------------------------------------------------------------
# 使用Google的开源TCMalloc库,忧化性能
 
cd /dist/src
tar zxf ../dist/libunwind-0.99.tar.gz
cd libunwind-0.99/
 
## 注意这里不能加其它 CFLAGS加速编译参数
 
CFLAGS=-fPIC ./configure
make clean
make CFLAGS=-fPIC
make CFLAGS=-fPIC install
if [ "$?" == "0" ]; then
        echo "libunwind-0.99安装成功." >> ./install_log.txt
else
        echo "libunwind-0.99安装失败." >> ./install_log.txt
        exit 1
fi
 
##----------------------------------------------------------
## 使用Google的开源TCMalloc库,提高MySQL在高并发情况下的性能
 
cd /dist/src
tar zxf ../dist/google-perftools-1.8.3.tar.gz
cd google-perftools-1.8.3/
 
CHOST="x86_64-pc-linux-gnu" CFLAGS="-march=nocona -O2 -pipe" CXXFLAGS="-march=nocona -O2 -pipe" \
./configure
 
make clean
make && make install
if [ "$?" == "0" ]; then
        echo "google-perftools-1.8.3安装成功." >> ./install_log.txt
else
        echo "google-perftools-1.8.3安装失败." >> ./install_log.txt
        exit 1
fi
 
echo "/usr/local/lib" > /etc/ld.so.conf.d/usr_local_lib.conf
/sbin/ldconfig
 
 
################ 安装nginx ##########################
#安装Nginx所需的pcre库
 
cd /dist/src
tar zxvf ../dist/pcre-8.01.tar.gz
cd pcre-8.01/
 
CHOST="x86_64-pc-linux-gnu" CFLAGS="-march=nocona -O2 -pipe" CXXFLAGS="-march=nocona -O2 -pipe" \
./configure
make && make install
if [ "$?" == "0" ]; then
        echo "pcre-8.01安装成功." >> ./install_log.txt
else
        echo "pcre-8.01安装失败." >> ./install_log.txt
        exit 1
fi
cd ../
 
 
## 安装Nginx
## 为优化性能,可以安装 google 的 tcmalloc ,之前己经安装过了
## 所以我们编译 Nginx 时,加上参数 --with-google_perftools_module
## 然后在启动nginx前需要设置环境变量 export LD_PRELOAD=/usr/local/lib/libtcmalloc.so
## 加上 -O2 参数也能优化一些性能
##
## 默认的Nginx编译选项里居然是用 debug模式的(-g参数),在 auto/cc/gcc 文件最底下,去掉那个 -g 参数
## 就是将  CFLAGS="$CFLAGS -g"  修改为   CFLAGS="$CFLAGS"   或者直接删除这一行
 
cd /dist/src
rm -rf nginx-1.0.5
tar zxf ../dist/nginx-1.0.5.tar.gz
cd nginx-1.0.5/
 
sed -i 's#CFLAGS="$CFLAGS -g"#CFLAGS="$CFLAGS "#' auto/cc/gcc
 
make clean
 
CHOST="x86_64-pc-linux-gnu" CFLAGS="-march=nocona -O2 -pipe" CXXFLAGS="-march=nocona -O2 -pipe" \
./configure --user=www --group=www \
--prefix=/usr/local/nginx \
--with-http_stub_status_module \
--with-google_perftools_module
 
make && make install
if [ "$?" == "0" ]; then
        echo "nginx-1.0.5安装成功." >> ./install_log.txt
else
        echo "nginx-1.0.5安装失败." >> ./install_log.txt
        exit 1
fi
cd ../
 
#创建Nginx日志目录
mkdir -p /data/logs
chmod +w /data/logs
chown -R www:www /data/logs
 
cd /usr/local/nginx/
mv conf conf_bak
ln -s /data/conf/nginx/ conf
 
echo 'export LD_PRELOAD=/usr/local/lib/libtcmalloc.so' > /root/nginx_start
echo 'ulimit -SHn 51200' >> /root/nginx_start
echo '/usr/local/nginx/sbin/nginx -c /usr/local/nginx/conf/nginx.conf' >> /root/nginx_start
 
echo '/usr/local/nginx/sbin/nginx -t' > /root/nginx_reload
echo 'kill -HUP `cat /usr/local/nginx/logs/nginx.pid`' >> /root/nginx_reload
 
chmod 700 /root/nginx_*

3.2 编译安装varnish

#!/bin/bash
 
#进入工作目录
cd /dist/dist
 
#下载安装包
wget http://bbs.osapub.com/down/varnish-3.0.0.tar.gz &> /dev/null
cd /dist/src
rm -fr varnish-3.0.0
export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig
tar zxvf ../dist/varnish-3.0.0.tar.gz
cd varnish-3.0.0
#编译参数可以根据自己需要定制
./configure -prefix=/usr/local/varnish -enable-debugging-symbols -enable-developer-warnings -enable-dependency-tracking
make && make install
if [ "$?" == "0" ]; then
        echo "varnish-3.0.0安装成功." >> ./install_log.txt
else
        echo "varnish-3.0.0安装失败." >> ./install_log.txt
        exit 1
fi
 
 
#设置启动、重启脚本
cat > /root/varnish_restart.sh <<EOF
#!/bin/bash
pkill varnish
pkill varnish
ulimit -SHn 51200
/usr/local/varnish/sbin/varnishd -n /data/varnish -f /usr/local/varnish/vcl.conf -a 0.0.0.0:81 -s malloc,12G -g www -u www -w 4000,12000,10 -T 127.0.0.1:3500 -p http_max_hdr=256 -p http_req_hdr_len=8192
EOF
 
cat > /root/varnish_start.sh <<EOF
#!/bin/bash
ulimit -SHn 51200
/usr/local/varnish/sbin/varnishd -n /data/varnish -f /usr/local/varnish/vcl.conf -a 0.0.0.0:81 -s malloc,12G -g www -u www -w 4000,12000,10 -T 127.0.0.1:3500 -p http_max_hdr=256 -p http_req_hdr_len=8192
EOF
 
chmod 755 /root/varnish*

三、 配置varnish

一些参数说明:
Backend servers
Varnish有后端(或称为源)服务器的概念。后端服务器是指Varnish提供加速服务的那台,通常提供内容。
第一件要做的事情是告诉Varnish,哪里能找到要加速的内容。
vcl_recv
vcl_recv是在请求开始时调用的。完成该子程序后,请求就被接收并解析了。用于确定是否需要服务请求,怎么服务,如果可用,使用哪个后端。
在vcl_recv中,你也可以修改请求。通常你可以修改cookie,或添加/移除请求头信息。
注意在vcl_recv中,只可以使用请求对象req。

vcl_fetch
vcl_fetch是在文档从后端被成功接收后调用的。通常用于调整响应头信息,触发ESI处理,万一请求失败就换个后端服务器。
在vcl_fecth中,你还可以使用请求对象req。还有个后端响应对象beresp。Beresp包含了后端的HTTP头信息。

varnish 3.X 配置参考文档:http://anykoro.sinaapp.com/?p=261

编辑:/usr/local/varnish/vcl.conf ,文件不存在则创建。注意:Server A 与server B 配置一致!

配置详情如下:

###########后台代理服务器########
 
backend server_osapub_com{
        .host = "192.168.4.97";
        .port = "82";
}
 
acl purge {
        "localhost";
                "127.0.0.1";       
}
 
 
#############################################
 
sub vcl_recv {
 
     #################BAN##########################begin
         if (req.request == "BAN") {
                # Same ACL check as above:
                if (!client.ip ~ purge) {
                        error 405 "Not allowed.";
                }
                ban("req.http.host == " + req.http.host +
                      "&& req.url == " + req.url);
                error 200 "Ban added";
        }
     #################BAN##########################end
 
         ###############配置域名##################################        
          if(req.http.host ~ "^server.osapub.com" ||req.http.host ~ ".osapub.com" ) {
 
                #使用哪一组后台服务器
                        set req.backend = server_osapub_com;
 
                }
 
 
                ##################################################
 
        if (req.restarts == 0) {
        if (req.http.x-forwarded-for) {
           set req.http.X-Forwarded-For = req.http.X-Forwarded-For + ", " + client.ip;
         }
         else {
            set req.http.X-Forwarded-For = client.ip;
         }
     }
 
 
        if (req.http.Accept-Encoding) {
        if (req.url ~ "\.(jpg|jpeg|png|gif|gz|tgz|bz2|tbz|mp3|ogg|swf)$") {
            remove req.http.Accept-Encoding;
        } elsif (req.http.Accept-Encoding ~ "gzip") {
            set req.http.Accept-Encoding = "gzip";}
          elsif (req.http.Accept-Encoding ~ "deflate") {
            set req.http.Accept-Encoding = "deflate";}
        else {
         remove req.http.Accept-Encoding;
      }
    }
     if (req.http.Cache-Control ~ "no-cache") {
         return (pass);
     }
     if (req.request != "GET" &&
       req.request != "HEAD" &&
       req.request != "PUT" &&
       req.request != "POST" &&
       req.request != "TRACE" &&
       req.request != "OPTIONS" &&
       req.request != "DELETE") {
         return (pipe);
     }
 
     if (req.request != "GET" && req.request != "HEAD") {
                        return(pass);
                }                
 
         if (req.http.Authorization || req.http.Cookie ||req.http.Authenticate) {
                 return (pass);
     }         
 
 
        if (req.request == "GET" && req.url ~ "(?i)\.php($|\?)"){
                return (pass);
             } 
 
        if (req.url ~ "\.(css|jpg|jpeg|png|gif|gz|tgz|bz2|tbz|mp3|ogg|swf)$") {
                unset req.http.Cookie;
        }            
 
        return (lookup);
 
 
}
 
 
sub vcl_fetch {
 
        set beresp.grace = 5m;
 
        if (beresp.status == 404 || beresp.status == 503 || beresp.status == 500 || beresp.status == 502) {
                set beresp.http.X-Cacheable = "NO: beresp.status";
                set beresp.http.X-Cacheable-status = beresp.status;
                return (hit_for_pass);
        }
 
        #决定哪些头不缓存
 
    if (req.url ~ "\.(php|shtml|asp|aspx|jsp|js|ashx)$") {
                return (hit_for_pass);
         }
 
 
        if (req.url ~ "\.(jpg|jpeg|png|gif|gz|tgz|bz2|tbz|mp3|ogg|swf)$") {
                unset beresp.http.set-cookie;
        }
 
        if (beresp.ttl <= 0s) {
                set beresp.http.X-Cacheable = "NO: !beresp.cacheable";
                return (hit_for_pass);
        }
        else {
                unset beresp.http.expires;
        }
 
 
        return (deliver);
 
}
 
sub vcl_deliver {
 
if (resp.http.magicmarker) {
 
     unset resp.http.magicmarker;
 
 
     set resp.http.age = "0";
 }
 
# add cache hit data
if (obj.hits > 0) {
 
   set resp.http.X-Cache = "HIT";
   set resp.http.X-Cache-Hits = obj.hits;
}
else {
     set resp.http.X-Cache = "MISS";
}
 
# hidden some sensitive http header returning to client, when the cache server received from backend server response
remove resp.http.X-Varnish;
remove resp.http.Via;
remove resp.http.Age;
remove resp.http.X-Powered-By;
remove resp.http.X-Drupal-Cache;
 
return (deliver);
}
 
sub vcl_error {
 
 if (obj.status == 503 && req.restarts < 5) {
   set obj.http.X-Restarts = req.restarts;
   return (restart);
 }
 
}
 
sub vcl_hit {
 
if (req.http.Cache-Control ~ "no-cache") {
 
  if (! (req.http.Via || req.http.User-Agent ~ "bot|MSIE")) {
      set obj.ttl = 0s;
      return (restart);
   }
}
  return(deliver);
}

配置完成后执行:/root/varnish_start.sh 如果启动成功则表示配置无误!

四、 配置nginx

编辑: /usr/local/nginx/conf/nginx.conf ,nginx 的配置方法请参考网上文档资料。
Server A(192.168.4.97) nginx配置如下:

user  www www;
worker_processes 16;
error_log /logs/nginx/nginx_error.log crit;
 
#Specifies the value for maximum file descriptors that can be opened by this process.
worker_rlimit_nofile 65500;
 
events
{
        use epoll;
 
        worker_connections 65500;
}
 
http
{
        include       mime.types;
        default_type  application/octet-stream;
 
 
        server_names_hash_bucket_size 128;
        client_header_buffer_size 64k;
        large_client_header_buffers 4 64k;
        client_max_body_size 10m;
 
        server_tokens off;
 
        expires       1h; 
 
        sendfile on;
        tcp_nopush     on;
        keepalive_timeout 60;
        tcp_nodelay on;
 
    fastcgi_connect_timeout 200;
    fastcgi_send_timeout 300;
    fastcgi_read_timeout 600;
    fastcgi_buffer_size 128k;
    fastcgi_buffers 4 64k;
    fastcgi_busy_buffers_size 128k;
    fastcgi_temp_file_write_size 128k;
    fastcgi_temp_path /dev/shm;
        gzip on;
        gzip_min_length  2048;
        gzip_buffers     4 16k;
        gzip_http_version 1.1;
        gzip_types  text/plain  text/css  application/xml application/x-javascript ;
 
        log_format  access  '$remote_addr - $remote_user [$time_local] "$request" '
                          '$status $body_bytes_sent "$http_referer" '
                          '"$http_user_agent" $http_x_forwarded_for';
 
#################  include  ###################
 
 
 
         upstream varnish_server {
                server 127.0.0.1:81 weight=2 max_fails=3 fail_timeout=30s;
                    server 192.168.4.99:81 weight=2 max_fails=3 fail_timeout=30s;
                ip_hash;
        }
 
 
                server
        {
                listen       80;
                server_name  192.168.4.96 192.168.4.98;
                             index index.html index.htm index.php index.aspx;              
                location /
                {
                        proxy_set_header   Host             $host;
                        proxy_set_header   X-Real-IP        $remote_addr;
                        proxy_set_header   X-Forwarded-For  $proxy_add_x_forwarded_for;
 
                        proxy_connect_timeout 200;
                        proxy_send_timeout 300;
                        proxy_read_timeout 500;
                        proxy_buffer_size 256k;
                        proxy_buffers 4 128k;
                        proxy_busy_buffers_size 256k;
                        proxy_temp_file_write_size 256k;
                        proxy_temp_path  /dev/shm;
 
                        proxy_pass  http://varnish_server;
 
                        expires off;
 
                        access_log  /logs/nginx/192.168.4.96.log  access;
                }
        }
 
                server
        {
              listen       82;
              server_name  192.168.4.97;
              index index.html index.htm index.php;
              root  /data/web/awstats/www;
 
              location ~ .*\.php$
              {
                   include fcgi.conf;
                   fastcgi_pass  127.0.0.1:10080;
                   fastcgi_index index.php;
                   expires off;
              }
              access_log  /logs/nginx/awstats.osapub.com.log  access;
        }                
 
}

server B (192.168.4.99)配置如下:

user  www www;
worker_processes 16;
error_log /logs/nginx/nginx_error.log crit;
 
#Specifies the value for maximum file descriptors that can be opened by this process.
worker_rlimit_nofile 65500;
 
events
{
        use epoll;
 
        worker_connections 65500;
}
 
http
{
        include       mime.types;
        default_type  application/octet-stream;
 
 
        server_names_hash_bucket_size 128;
        client_header_buffer_size 64k;
        large_client_header_buffers 4 64k;
        client_max_body_size 10m;
 
        server_tokens off;
 
        expires       1h; 
 
        sendfile on;
        tcp_nopush     on;
        keepalive_timeout 60;
        tcp_nodelay on;
 
    fastcgi_connect_timeout 200;
    fastcgi_send_timeout 300;
    fastcgi_read_timeout 600;
    fastcgi_buffer_size 128k;
    fastcgi_buffers 4 64k;
    fastcgi_busy_buffers_size 128k;
    fastcgi_temp_file_write_size 128k;
    fastcgi_temp_path /dev/shm;
        gzip on;
        gzip_min_length  2048;
        gzip_buffers     4 16k;
        gzip_http_version 1.1;
        gzip_types  text/plain  text/css  application/xml application/x-javascript ;
 
        log_format  access  '$remote_addr - $remote_user [$time_local] "$request" '
                          '$status $body_bytes_sent "$http_referer" '
                          '"$http_user_agent" $http_x_forwarded_for';
 
#################  include  ###################
 
 
 
         upstream varnish_server {
                server 127.0.0.1:81 weight=2 max_fails=3 fail_timeout=30s;
                    server 192.168.4.97:81 weight=2 max_fails=3 fail_timeout=30s;
                ip_hash;
        }
 
 
                server
        {
                listen       80;
                server_name  192.168.4.96 192.168.4.98;
                             index index.html index.htm index.php index.aspx;              
                location /
                {
                        proxy_set_header   Host             $host;
                        proxy_set_header   X-Real-IP        $remote_addr;
                        proxy_set_header   X-Forwarded-For  $proxy_add_x_forwarded_for;
 
                        proxy_connect_timeout 200;
                        proxy_send_timeout 300;
                        proxy_read_timeout 500;
                        proxy_buffer_size 256k;
                        proxy_buffers 4 128k;
                        proxy_busy_buffers_size 256k;
                        proxy_temp_file_write_size 256k;
                        proxy_temp_path  /dev/shm;
 
                        proxy_pass  http://varnish_server;
 
                        expires off;
 
                        access_log  /logs/nginx/192.168.4.98.log  access;
                }
        }
 
                server
        {
              listen       82;
              server_name  192.168.4.99;
              index index.html index.htm index.php;
              root  /data/web/awstats/www;
 
              location ~ .*\.php$
              {
                   include fcgi.conf;
                   fastcgi_pass  127.0.0.1:10080;
                   fastcgi_index index.php;
                   expires off;
              }
              access_log  /logs/nginx/awstats.osapub.com.log  access;
        }                
 
}

启动nginx:
/root/nginx_start
启动正常会监听80,82端口!

五、 运行nginx ha脚本
server A 的脚本下载地址:

下载地址

解压力后得到三个脚本:
nginx_watchdog.sh
nginxha.sh
nginx_ha1.sh
server B 的脚本下载地址:
下载地址

解压力后得到三个脚本:
nginx_watchdog.sh
nginxha.sh
nginx_ha2.sh

注意:脚本建议放到:/data/sh/ha 目录下,否则需要修改nginxha.sh 里面的程序路径!

六、 测试

1,测试之前先把nginx 负载去掉,可以在前面加#号暂时注释,只保留本机解析,确保测试结果准确。

2,修改本机host文件
添加:192.168.4.99 server.osapub.com 到末尾,保存后访问。

3,正常结果显示如下:

到这里整个架构基本能运行起来了,根据大家的实际需求,对配置文件进行调优,HA脚本也可以进一步调优,关于报警,请参考社区自动安装mutt报警的脚本!

没有完美的架构,只有不断完善的,不断调优的应用,欢迎大家多多指点,多多讨论!

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