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 <a href="\"http://bbs.osapub.com/down/varnish-3.0.0.tar.gz\"" target="\"_blank\"">http://bbs.osapub.com/down/varnish-3.0.0.tar.gz</a> &> /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：http://bbs.osapub.com/down/server_a_ha.tar.gz
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：http://bbs.osapub.com/down/server_b_ha.tar.gz
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！
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