系统环境
两台Nginx:
CentOS6.5 x86_64
两台tomcat:
CentOS6.5 x86_64
拓扑图
机器IP |
安装软件 |
角色
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|
虚拟ip |
描述 |
192.168.1.132 |
Nginx、keepalived |
Nginx主机 |
192.168.1.135 |
反向代理到tomcat1和tomcat2 |
192.168.1.133 |
Nginx、keepalived |
Nginx备机 |
主机挂了切换虚拟ip192.168.1.135 |
反向代理到tomcat1和tomcat2 |
192.168.1.128 |
Tomcat |
Tomcat1 |
无 |
|
192.168.1.30 |
Tomcat |
Tomcat2 |
无 |
IP分配
nginx(主LB):192.168.1.132
nginx(备LB):192.168.1.133
VIP地址:192.168.1.135
Real1的IP:192.168.1.128
Real2的IP:192.168.1.30
然后
在192.168.1.128和192.168.1.30上分别解压修改tomcat的index页面:
vi webapps/ROOT/index.jsp
修改页面html部分
<html>
<head>
</head>
<body>
SessionID:<%=session.getId()%>
<br/>
SessionIP:<%=request.getServerName()%>
<br/>
<h1>tomcat1 page</h1>
</body>
</html>
这样可以通过访问index来判断访问是不是轮询的
二、安装配置Nginx
1.用yum命令安装GCC编译器等环境依赖包:
yum install -y gcc gcc-c++ autoconf automake libtool make openssl openssl-devel pcre pcre-devel
2.下载安装Nginx:
wget http://nginx.org/download/nginx-1.11.8.tar.gz
注:这里也可以下载tengine压缩包,比一般nginx多一些功能
tar -zxvf nginx-1.11.8.tar.gz
cd nginx-1.11.8/
./configure --prefix=/usr/local/nginx
--sbin-path=/usr/local/nginx/sbin/nginx
--conf-path=/usr/local/nginx/conf/nginx.conf
--pid-path=/usr/local/nginx/logs/nginx.pid \
--with-http_ssl_module \
--with-http_stub_status_module \
--with-http_gzip_static_module \
make && make install
注:查询"./configure --help"相关模块,按需求指定启用
3.配置Nginx.conf
配置文件,二个nginx负载均衡器的文件一样
user nobody; worker_processes 1; error_log /usr/local/nginx/logs/error.log notice; pid /usr/local/nginx/logs/nginx.pid; worker_rlimit_nofile 51200; events { use epoll; worker_connections 51200; } http { 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; server_names_hash_bucket_size 128; client_header_buffer_size 32k; large_client_header_buffers 4 32k; client_max_body_size 8m; sendfile on; tcp_nopush on; server_tokens off; keepalive_timeout 60; fastcgi_connect_timeout 300; fastcgi_send_timeout 300; fastcgi_read_timeout 300; fastcgi_buffer_size 64k; fastcgi_buffers 4 64k; fastcgi_busy_buffers_size 128k; fastcgi_temp_file_write_size 128k; gzip on; upstream backend { server 192.168.1.128; server 192.168.1.130; } server { listen 80; server_name 192.168.1.135; location / { root html; index index.php index.html index.htm; proxy_redirect off; proxy_set_header Host $host; proxy_set_header X-Real-IP $remote_addr; #后端的Web服务器可以通过X-Forwarded-For获取用户真实IP proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_pass http://backend; } error_page 500 502 503 504 /50x.html; location = /50x.html { root html; }
location /nginx_status { stub_status on; auth_basic "NginxStatus"; auth_basic_user_file /usr/local/nginx/htpasswd; #allow 127.0.0.1; #deny all; } location ~* \.(ini|docx|txt|doc|pdf)$ { #禁止访问文档性文件 root /usr/share/nginx/html; deny all; } location ~ .*\.(gif|jpg|jpeg|png|bmp|swf|js|html|htm|css)$ { root /home/image; proxy_store on; proxy_store_access user:rw group:rw all:rw; proxy_temp_path /home/image; if ( !-e $request_filename) { proxy_pass http://backend; } } } } |
三.安装及配置keepalived
1.安装keepalived
在两台nginx服务器张安装keepalived:
wget http://www.keepalived.org/software/keepalived-1.2.15.tar.gz
tar -zxvf keepalived-1.2.15.tar.gz
cd keepalived-1.2.15
./configure --sysconf=/etc/ --with-kernel-dir=/usr/src/kernels/2.6.32-573.8.1.el6.x86_64
make && make install
ln -s /usr/local/sbin/keepalived /sbin/
注意:这里有坑,
#这一步很重要,不执行ln -s会报错“Starting keepalived: /bin/bash: keepalived: command not found”
service keepalived start
二台Nginx上keepalived.conf配置文件如下,配置完成后分别service keepalived start启动。检验keepalived配置是否成功
两台keepalived的配置如下:可以看出两者之间的区别仅仅是主备的权重不同,主为100备为66,其余一些有作用的配置已经用红色标注
主:
global_defs { notification_email { } notification_email_from keepalived@localhost smtp_server 127.0.0.1 smtp_connect_timeout 30 router_id LVS_MASTER } vrrp_script chk_http_port { #这里是写的一个检测脚本 script "/usr/local/src/check_nginx_pid.sh" interval 2 #(检测脚本执行的间隔) weight 2 } vrrp_instance VI_1 { #state MASTER state BACKUP nopreempt #设置非抢占模式时,修改“state MASTER”为“state BACKUP”,添加“nopreempt“ interface bond0 virtual_router_id 51 priority 100 advert_int 1 authentication { auth_type PASS auth_pass 1111 } track_script { chk_http_port #(调用检测脚本) } virtual_ipaddress { 192.168.1.135 } } |
备:
global_defs { notification_email { } notification_email_from keepalived@localhost smtp_server 127.0.0.1 smtp_connect_timeout 30 router_id LVS_BACKUP } vrrp_script chk_http_port { script "/usr/local/src/check_nginx_pid.sh" interval 2 #(检测脚本执行的间隔) weight 2 } vrrp_instance VI_1 { state BACKUP interface bond0 virtual_router_id 51 priority 66 #优先级别 advert_int 1 authentication { auth_type PASS auth_pass 1111 } track_script { chk_http_port #(调用检测脚本) } virtual_ipaddress { 192.168.1.135 } } |
以下是针对nginx状态进行检测的脚本check_nginx_pid,
vim /usr/local/src/check_nginx_pid.sh
#!/bin/bash A=`ps -C nginx --no-header |wc -l` if [ $A -eq 0 ];then /usr/local/nginx/sbin/nginx if [ `ps -C nginx --no-header |wc -l` -eq 0 ];then killall keepalived fi |
ps -C nginx --no-header | wc -l 大家可能疑惑
--no-header就是去掉表头的
ps --help|grep C 可以使用帮助命令,看看 -C是什么意思 -A all processes -C by command name -V,V show version L list format codes f ASCII art forest -w,w wide output n numeric WCHAN,UID -H process hierarchy #-C 跟命令的名子(nginx)
wc -l 是统计行数,其他的自行补脑吧
这个脚本的作用是检测Nginx服务状态的
第一次 nginx 服务死掉时,会重新启动,如果 Nginx 服务无法正常启动,则杀掉 keepalived 进程
最后
依次启动两个tomcat=》启动两个nginx=》启动两个keepalived,查看主机上是否有虚拟ip 192.168.15135
通过虚拟ip访问nignx,看页面是不是轮询两个tomcat
将主机的nginx进程kill -9掉,看看vip是不是切换到备机器上了,kill -9是kill掉所有相关进程
访问虚拟ip是不是还能轮询访问tomcat
好了,到此就是负载均衡的全部内容,有坑自补!