nginx+keepalived 高可用兼负载均衡集群

 

nginx+keepalived 高可用兼负载均衡集群

 

 

版本	作者	联系方式	最后更新
v0.3	purplegrape	[email protected]	2013-04-10

 

Nginx是一个高性能的web服务器，同时也是一个优秀的反向代理服务器，本文利用两台Dell R720 构建一个高可用兼负载均衡的Linux web集群。

 

原理

 

通过nginx分别搭建两个web服务器，监听在本地非80端口；

然后利用nginx构建一个包含两个节点的负载均衡池；

最后通过keepalived实现负载均衡池的高可用。两个节点同时运行时，备用节点可以承载一半的前端流量，一个节点宕机后，负载均衡器通过健康检查，将失效节点踢出集群。

 

环境：CentOS 6.4 x86_64

 

软件	版本
nginx	1.2.7
keepalived	1.2.7
php-fpm	5.4.13

 

主机名	IP地址
web01	192.168.122.10
web02	192.168.122.20
VIP	192.168.122.30

 

 

安装nginx、keepalived和php-fpm等（编译过程略）

 

yum install nginx keepalived php-fpm php-gd php-xml php-mysql php-pecl-memcached php-pecl-sphinx watchodg -y chkconfig nginx on chkconfig keepalived on chkconfig php-fpm on chkconfig watchdog on

 

 

配置nginx

 

nginx主配置文件 /etc/nginx/nginx.conf

user nginx; worker_processes 2; worker_rlimit_nofile 65535; error_log /var/log/nginx/error.log warn; pid /var/run/nginx.pid; events { use epoll; worker_connections 2048; } http { include /etc/nginx/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 /var/log/nginx/access.log main; sendfile on; server_tokens off; #tcp_nopush on; keepalive_timeout 65; gzip on; gzip_static on; gzip_disable "msie6"; gzip_http_version 1.1; gzip_vary on; gzip_comp_level 6; gzip_proxied any; gzip_types text/plain text/css application/json application/x-javascript text/xml application/xml application/xml+rss text/javascript application/javascript text/x$ gzip_buffers 16 8k; client_max_body_size 20m; client_body_buffer_size 128k;   proxy_hide_header Vary; proxy_connect_timeout 600; proxy_read_timeout 600; proxy_send_timeout 600; proxy_buffer_size 16k; proxy_buffers 4 64k; proxy_busy_buffers_size 128k; #proxy_temp_file_write_size 128k   proxy_temp_path /dev/shm/tmp; proxy_cache_path /dev/shm/proxycache/ levels=1:2 keys_zone=shmcache:10m inactive=2h max_size=500m;   include /etc/nginx/conf.d/*.conf; }

 

 

网站主配置文件/etc/nginx/conf.d/default.conf

upstream webservers { ip_hash ; server 192.168.122.10:88 max_fails=3 fail_timeout=3s weight=2 ; server 192.168.122.20:88 max_fails=3 fail_timeout=3s weight=2 ; } server { listen 80 ; server_name localhost ; access_log /var/log/nginx/web01.access.log main; location / { proxy_redirect off; proxy_pass http://webservers ;   proxy_cache shmcache; proxy_cache_valid 200 302 1d; proxy_cache_valid 404 1h; proxy_cache_valid any 10m; proxy_cache_use_stale error timeout invalid_header updating http_500 http_502 http_503 http_504;   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_next_upstream error timeout invalid_header http_500 http_502 http_504; } location /status { stub_status on; access_log off; allow 192.168.122.0/24; } } server { listen 192.168.122.10:88; server_name localhost; root /usr/share/nginx/html; index index.html index.htm index.php; #charset koi8-r; location / { if (!-e $request_filename) { rewrite ^/(.*)$ /index.php?q=$1 last; } } #error_page 404 /404.html; # redirect server error pages to the static page /50x.html # error_page 500 502 503 504 /50x.html; # proxy the PHP scripts to Apache listening on 127.0.0.1:80 # #location ~ \.php$ { # proxy_pass http://127.0.0.1; #} # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000 # location ~ \.php$ { #try_files $uri = 404; fastcgi_pass 127.0.0.1:9000; #fastcgi_pass unix:/var/run/php-fpm/php-fpm.sock; fastcgi_index index.php; fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name; fastcgi_buffer_size 128k; fastcgi_buffers 256 16k; fastcgi_busy_buffers_size 256k; fastcgi_temp_file_write_size 256k; fastcgi_read_timeout 240; include fastcgi_params; } if ($fastcgi_script_name ~ \..*\/.*php) { return 403; } # deny access to hiden file . (filename begin with ".") location ~ /\. { access_log off; log_not_found off; deny all; } # deny access to bakup file .(any filename end with "~" ) location ~ ~$ { access_log off; log_not_found off; deny all; } # cache image file location ~* \.(jpg|jpeg|gif|png|css|js|ico|xml|swf)$ { expires 1d; } # don't log robots and favion location = /robots.txt { access_log off; log_not_found off; } location = /favicon.ico { access_log off; log_not_found off; } # deny access to .htaccess files, if Apache's document root # concurs with nginx's one # location ~ /\.ht { deny all; } }

 

配置php-fpm

php-fpm全称php fastcgi process manager，用于管理php的fastcgi进程，自从php5.3.3之后集成进了php源码中。默认的php-fpm用户是apache，我们需要修改成nginx，代码：

 

sed -i 's/apache/nginx/g' /etc/php-fpm.d/www.conf

 

 

配置keepalived

keepalived是一个高可用软件，通过vrrp心跳来检测对方是否存活。

 

keepalived主配置文件

global_defs { notification_email { root@localhost } notification_email_from [email protected] smtp_server 127.0.0.1 smtp_connect_timeout 30 } vrrp_instance VI_1 { state MASTER interface eth0 virtual_router_id 51 priority 100 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 192.168.122.30 label eth0:1 } }

 

配置watchdog

 

watchdog是个健壮可靠的内核模块，即使在高负载的系统中仍然可以存活。它能够执行检测脚本，定时检查nginx和keepalived进程是否存在，如果不存在可以重新开启进程。

 

watchdog主配置文件/etc/watchdog.conf

min-memory = 1 repair-binary = /etc/watchdog.d/repair.sh test-binary = /etc/watchdog.d/test.sh test-timeout = 5 watchdog-device = /dev/watchdog admin = root interval = 10 logtick = 1 realtime = yes priority = 1 pidfile = /var/run/syslogd.pid pidfile = /var/run/nginx.pid pidfile = /var/run/keepalived.pid pidfile = /var/run/php-fpm/php-fpm.pid

 

 

 

测试脚本，权限751

#!/usr/bin/env bash #author:purplegrape #desc: shell script to check if keepalived/nginx/php-fpm down.   keepalived_proc=`pgrep keepalived |wc -l` nginx_proc=`pgrep nginx|wc -l` php_fpm_porc=`pgrep php-fpm|wc -l`   if [$keepalived_proc == 0 ];then exit 1 fi   if [$nginx_proc == 0 ];then exit 1 fi   if [$php_fpm_proc == 0 ];then exit 1 fi

 

修复脚本,权限751

#!/usr/bin/env bash #author:purplegrape #desc: shell script to repair keepalived/nginx/php-fpm.   keepalived_proc=`pgrep keepalived |wc -l` nginx_proc=`pgrep nginx|wc -l` php_fpm_proc=`pgrep php-fpm|wc -l`   if [$keepalived_proc == 0 ];then wall “keepalived is dead” /etc/init.d/keepalived restart sleep 30 /etc/init.d/nginx restart fi   if [$nginx_proc == 0 ];then if [$keepalived_proc != 0 ];then wall “nginx is dead” /etc/init.d/nginx restart fi fi   if [ $php_fpm_proc == 0 ]; then wall “php-fpm is dead” /etc/init.d/php-fpm restart fi

 

测试

打开浏览器，访问地址http://192.168.122.30