使用keepalived+nginx+tomcat搭建高性能web服务器集群，系统采用centos6.9，前端用nginx做反向代理实现负载均衡，同时结合keepalived对nginx实现高可用，后端使用两台tomcat做动态jsp解析，实现了动静分离。
搭建环境
准备四台服务器
vip: 192.168.75.130
master: 192.168.75.131 (安装nginx做反向代理实现负载匀衡，结合keepalived实现高可用）
backup: 192.168.75.132 (同上)
web1: 192.168.75.151 (安装nginx和tomcat实现动静分离)
web2: 192.168.75.152 (同上)
这里为节省服器，nginx和tomcat和装在了一台服务上，也可以分开配置。
配置步骤如下：
四台服务器分别安装好nginx
安装方法参见：LNMP环境搭建
web1，web2上分别安装好tomcat
安装方法参见：Tomcat8.5的安装配置
web1, web2上分别启动nginx和tomcat
service nginx start
service tomcat start
在master和backup上配置nginx：
vi /usr/local/nginx/conf/nginx.conf
加入或修改以下内容：
upstream web_nginx {
#ip_hash;
server 192.168.75.151;
server 192.168.75.152;
}
upstream web_tomcat {
server 192.168.75.151:8080;
server 192.168.75.152:8080;
}
server {
listen 80;
server_name localhost;
#charset koi8-r;
#access_log logs/host.access.log main;
location / {
proxy_pass http://web_nginx/;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
}
location ~ \.jsp$ {
proxy_pass http://web_tomcat;
}
分别在master和backup上启动nginx服务
service nginx start
在master和backup上分别安装keepalived
yum install -y keepalived
配置master
vi /etc/keepalived/keepalived.conf
清空原文，加入如下内容：
! Configuration File for keepalived
global_defs {
notification_email {
#[email protected]
#[email protected]
#[email protected]
}
#notification_email_from [email protected]
#smtp_server 192.168.200.1
#smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_script chk_http_port {
script "</dev/tcp/127.0.0.1/80"
interval 1
weight -2
}
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 {
192.168.75.130
}
track_script {
chk_http_port
}
}
配置backup
scp 192.168.75.131:/etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf
vi /etc/keepalived/keepalived.conf
backup的配置文件只需要修改
state MASTER -> state BACKUP
priority 100 -> priority 99
最后，分别在master和backup上启动keepalived服务，先主后备
/etc/init.d/keepalived start