拓扑图：
环境描述：
操作系统：CentOS6.4_x64
master-nginx均衡器：192.168.0.202
backup-nginx均衡器：192.168.0.203
后端web1：192.168.0.204
后端web2：192.168.0.205
VTP：192.168.0.200
一、安装nginx
1、安装依赖包和创建用户和组
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# yum install -y gcc gcc-c++ make kernel-headers glibc-headers zlib-devel openssl openssl-devel pcre-devel
# groupadd nginx
# useradd -g nginx -s /sbin/nologin nginx
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2、安装nginx
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# tar zxvf nginx-1.4.2.tar.gz
# cd nginx-1.4.2
# ./configure --prefix=/usr/local/nginx --user=nginx --group=nginx --with-http_ssl_module --with-http_gzip_static_module --with-http_stub_status_module
# make && make install
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二、配置主配置文件
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# vi /usr/local/nginx/conf/nginx.conf
user nginx nginx;
worker_processes 8;
error_log logs
/error
.log;
pid logs
/nginx
.pid;
events {
worker_connections 1024;
}
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;
#上面是访问日志格式和记录位置
sendfile on;
tcp_nopush on;
keepalive_timeout 65;
gzip
on;
upstream www.
test
.com {
server 192.168.0.203:80 weight=2;
server 192.168.0.204:80 weight=2;
}
server {
listen 80;
server_name www.
test
.com;
location / {
root html;
index index.html index.htm;
#请求转向mysvr 定义的服务器列表
proxy_pass http:
//www
.
test
.com;
proxy_headers_hash_max_size 51200;
#设置头部哈希表的最大值，不能小于你后端服务器设置的头部总数。
proxy_headers_hash_bucket_size 6400;
#设置头部哈希表大小
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
include proxy.conf;
}
}
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# vi /usr/local/nginx/conf/proxy.conf
proxy_redirect off;
proxy_set_header Host $host;
#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-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
client_max_body_size 10m;
#允许客户端请求的最大单文件字节数
client_body_buffer_size 128k;
#缓冲区代理缓冲用户端请求的最大字节数，
proxy_connect_timeout 90;
#nginx跟后端服务器连接超时时间(代理连接超时)
proxy_read_timeout 90;
#连接成功后，后端服务器响应时间(代理接收超时)
proxy_buffer_size 4k;
#设置代理服务器（nginx）保存用户头信息的缓冲区大小
proxy_buffers 6 32k;
#proxy_buffers缓冲区，网页平均在32k以下的话，这样设置
proxy_busy_buffers_size 64k;
#高负荷下缓冲大小（proxy_buffers*2）
proxy_temp_file_write_size 64k;
#设定缓存文件夹大小，大于这个值，将从upstream服务器传
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三、安装主从keepalived （配置基本一样，主配置文件稍作修改）
1、安装依赖包：
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# yum install -y pcre pcre-devel openssl-devel lftp libnl-devel popt*
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2、安装keepalived
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# wget http://www.keepalived.org/software/keepalived-1.2.7.tar.gz
# tar zxvf keepalived-1.2.7.tar.gz
# cd keepalived-1.2.7
# ./configure --prefix=/usr/local/keepalived
# make && make install
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3、keepalived配置成系统服务
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# cp /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/
# cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
# mkdir /etc/keepalived/
# cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/
# cp /usr/local/keepalived/sbin/keepalived /usr/sbin/
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4、修改keepalived主配置
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# vi /etc/keepalived/keepalived.conf
! Configuration File
for
keepalived
global_defs {
notification_email {
test
@sina.com
#故障联系人
}
notification_email_from admin@
test
.com
#故障发送人
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_MASTER
#BACKUP上修改为LVS_BACKUP
}
vrrp_script check_nginx {
script
"/usr/local/nginx/check_nginx.sh"
#检测nginx脚本路径
interval 2
#监控时间/秒
}
vrrp_instance VI_1 {
state MASTER
#BACKUP上修改为BACKUP
interface eth0
virtual_router_id 51
priority 100
#BACKUP上修改为90
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
track_script {
#实例引用脚本
check_nginx
}
virtual_ipaddress {
#VTP
192.168.0.203
192.168.0.204
}
}
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5、编写nginx_local.sh脚本
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# vi check_nginx.sh
#!/bin/bash
Count1=`
netstat
-antp |
grep
-
v
grep
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grep
nginx |
wc
-l`
if
[ $Count1 -
eq
0 ];
then
/usr/local/nginx/sbin/nginx
Count2=`
netstat
-antp |
grep
-
v
grep
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grep
nginx |
wc
-l`
if
[ $Count2 -
eq
0 ];
then
service keepalived stop
else
exit
0
fi
else
exit
0
fi
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6、重新启动
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# service keepalived restart
# /usr/local/nginx/sbin/nginx -s reload
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四、其他说明
实验中遇到一个问题，当keepalived或服务器没有DOWN时，主从服务器不会切换，所以就使用vrrp_script功能，写了个简单的检测脚本，nginx服务启动不起来时，就关闭keepalived，从而确保能主从切换。
1.常用命令：
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# ipvsadm -ln #显示集群中服务器ip信息
# ip add #显示VTP绑定在哪个服务器上
# /usr/local/nginx/sbin/nginx #启动nginx
# /sbin/nginx -s stop #快速终止web服务
# /sbin/nginx -s quit #有安排的结束web服务
# /sbin/nginx -s reload #重新加载相关配置
# echo '/usr/local/nginx/sbin/nginx' >> /etc/rc.local #设置开机启动
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2.tail -f /var/log/messger(从日志中可知，主机出现故障后，备机立刻检测到，此时备机变为MASTER角色，并且接管了主机的虚拟IP资源，最后将虚拟IP绑定在eth0设备上)
3.当主LVS恢复后，会切换成主动服务器，如果Keepalived监控模块检测web故障恢复后，恢复的wen主机又将此节点加入集群系统中。
本文转自 李振良OK 51CTO博客，原文链接：http://blog.51cto.com/lizhenliang/1301457，如需转载请自行联系原作者
