操作系统：centos6.4 x64
前端使用nginx做反向代理，后端服务器为：apache + php + mysql
1. nginx负载均衡。
nginx编译安装（编译安装前面的文章已经写过）、apache + php + mysql 直接使用yum安装。
nginx端口：80
apache端口：800 和 8080
nginx配置如下：
在http节点下添加如下：
upstream backend {
ip_hash; server 127.0.0.1:8080 weight=5 max_fails=2 fail_timeout=30s; server 127.0.0.1:800 weight=10 max_fails=2 fail_timeout=30s; }
将server节点下的location节点中添加proxy_pass 配置为:http://+upstream名称
location / { proxy_pass http://backend; #root html; #index index.html index.htm; }
这样负载均衡就已经完成了。upstream策略如下：
weight 权重
指定轮询几率，weight和访问比率成正比，用于后端服务器性能不均的情况。上面的情况：127.0.0.1:800访问到的几率要比127.0.0.1:8080高一倍。
ip_hash:
每个请求按访问IP的hash结果分配，这样每个访客固定访问一个后端服务器，可以解决session的问题。
upstream还可以为每个设备设置状态值，这些状态如下：
down 表示当前的server暂时不参与负载。
weight 默认为1，weight越大，负载的权重就越大。
max_fails 允许请求失败的次数默认为1，当超过最大次数时，返回proxy_next_upstream模块定义的错误。
fail_timeout max_fails次失败后，暂停的时间。
backup 其他所有的非backup机器down或者忙的时候，请求backup机器。所以这台机器压力是最小的。
2. nginx缓存设置
建议：在设置nginx缓存时，最好能编译安装ngx_purge_module 模块。
[root@cloud conf]# nginx -V nginx version: nginx/1.9.9 built by gcc 4.4.7 20120313 (Red Hat 4.4.7-3) (GCC) built with OpenSSL 1.0.1e-fips 11 Feb 2013 TLS SNI support enabled configure arguments: --prefix=/usr/local/nginx --user=nginx --group=nginx --add-module=../ngx_cache_purge-2.3
--with-http_ssl_module --with-http_stub_status_module --with-http_gzip_static_module --with-pcre --with-http_realip_module
nginx 全部相关配置如下：
user nginx 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; worker_rlimit_nofile 65535; events { use epoll; multi_accept on; worker_connections 4096; } http { server_tokens off; 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; open_log_file_cache max=2000 inactive=20s min_uses=2 valid=1m; proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; limit_conn_zone $binary_remote_addr zone=addr:5m; limit_conn addr 100; sendfile on; tcp_nopush on; #keepalive_timeout 0; keepalive_timeout 65; client_header_timeout 2m; client_body_timeout 3m; reset_timedout_connection on; send_timeout 15s; client_max_body_size 10m; client_body_buffer_size 512k; open_file_cache max=65535 inactive=20s; open_file_cache_valid 30s; open_file_cache_errors on; open_file_cache_min_uses 2; gzip on; gzip_disable "msie6"; gzip_proxied any; gzip_comp_level 4; gzip_vary on; gzip_min_length 1k; gzip_types text/plain text/css application/json application/x-javascript text/xml application/xml application/xml+rss text/javasc ript; proxy_connect_timeout 5; proxy_read_timeout 60; proxy_send_timeout 5; proxy_buffer_size 16k; proxy_buffers 4 64k; proxy_busy_buffers_size 128k; proxy_temp_file_write_size 128k;
#注：proxy_temp_path和proxy_cache_path指定的路径必须在同一分区 proxy_temp_path /cache/proxy_temp_dir; # 创建临时缓存目录
#设置Web缓存区名称为cache_one，内存缓存空间大小为200MB，1天没有被访问的内容自动清除，硬盘缓存空间大小为30GB。 proxy_cache_path /cache/proxy_cache_dir levels=1:2 keys_zone=cache_one:200m inactive=1d max_size=30g;
upstream backend { ip_hash; server 127.0.0.1:8080 weight=5 max_fails=2 fail_timeout=30; server 127.0.0.1:800 weight=10 max_fails=2 fail_timeout=30; } server { listen 80; server_name localhost; #charset koi8-r; #access_log logs/host.access.log main; location / {
#如果后端的服务器返回502、504、执行超时等错误，自动将请求转发到upstream负载均衡池中的另一台服务器，实现故障转移。
proxy_next_upstream http_502 http_504 error timeout invalid_header; proxy_pass http://backend; proxy_cache cache_one; proxy_cache_valid 200 304 12h; #对不同的HTTP状态码设置不同的缓存时间
#以域名、URI、参数组合成Web缓存的Key值，Nginx根据Key值哈希，存储缓存内容到二级缓存目录内
proxy_cache_key $host$uri$is_args$args; expires 1d; #root html; #index index.html index.htm; } location ~ /purge(/.*) { proxy_cache_purge cache_one $host$1$is_args$args; } #error_page 404 /404.html; # redirect server error pages to the static page /50x.html # error_page 500 502 503 504 /50x.html; location = /50x.html { root html; } # proxy the PHP scripts to Apache listening on 127.0.0.1:80 # #location ~ .php$ { # proxy_pass http://127.0.0.1; #} # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000 # #location ~ .php$ { # root html; # fastcgi_pass 127.0.0.1:9000; # fastcgi_index index.php; # fastcgi_param SCRIPT_FILENAME /scripts$fastcgi_script_name; # include fastcgi_params; #} # deny access to .htaccess files, if Apache's document root # concurs with nginx's one # #location ~ /.ht { # deny all; #} } # another virtual host using mix of IP-, name-, and port-based configuration # #server { # listen 8000; # listen somename:8080; # server_name somename alias another.alias; # location / { # root html; # index index.html index.htm; # } #} # HTTPS server # #server { # listen 443 ssl; # server_name localhost; # ssl_certificate cert.pem; # ssl_certificate_key cert.key; # ssl_session_cache shared:SSL:1m; # ssl_session_timeout 5m; # ssl_ciphers HIGH:!aNULL:!MD5; # ssl_prefer_server_ciphers on; # location / { # root html; # index index.html index.htm; # } #} }