使用nginx+tomcat+keepalived实现高可用的详细步骤

架构设计

IP	服务应用
192.168.166.128	nginx/tomcat/keepalived
192.168.166.129	nginx/tomcat/keepalived
192.168.166.130	虚拟IP

我这是测试环境，防火墙全部关闭了。

# 查看防火墙状态
systemctl status firewalld
# 关闭防火墙
systemctl stop firewalld

安装tomcat服务

192.168.166.128

在tomcat服务webapps下创建一个目录：zkc
当前目录：

mdkir -p webapps/zkc
echo "192.168.166.128" >> webapps/zkc/a.html
#启动tomcat
./bin/startup.sh

访问地址：http://192.168.166.128:8080/zkc/a.html

192.168.166.129

在tomcat服务webapps下创建一个目录：zkc
当前目录：

mdkir -p webapps/zkc
echo "192.168.166.129" >> webapps/zkc/a.html
#启动tomcat
./bin/startup.sh

访问地址：http://192.168.166.129:8080/zkc/a.html

安装nginx服务

可以直接到官网下载或者通过yum下载
两台机器安装步骤一样

# 安装nginx
yum -y install nginx
# 进入配置文件目录
cd /etc/nginx/
# 修改配置文件
vim nginx.conf

upstream app_server{
        server  192.168.166.128:8080 weight=1 max_fails=1 fail_timeout=100;
        server  192.168.166.129:8080 weight=1 max_fails=1 fail_timeout=100;
        }
    server {
        listen       80;
        listen       [::]:80;
        server_name  _;
        root         /usr/share/nginx/html;
        # Load configuration files for the default server block.
        include /etc/nginx/default.d/*.conf;
        location /zkc {
                proxy_set_header Host $host:$server_port;
                proxy_set_header X-Real-IP $remote_addr;
                proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
                proxy_connect_timeout 10;
                proxy_read_timeout 600;
                proxy_send_timeout 600;
                proxy_pass http://app_server;
                access_log /var/log/nginx/access-app.log main;
    }
# 启动
nginx

访问： curl http://192.168.166.128/zkc/a.html

访问：curl http://192.168.166.129/zkc/a.html

安装keepalived

安装keepalived两台机器一样
可以上网下载keepalived或者通过yum安装

# 安装
yum -y install keepalived
cd /etc/keepalived/
# 创建检测文件
vim chk_nginx.sh
# 赋予可执行权限
chmod +x chk_nginx.sh

chk_nginx.sh 内容

#!/bin/bash
status=$(ps aux|grep nginx | grep -v grep | grep -v bash | wc -l)
#echo $status >> check.log
if [ "${status}" = "0" ]; then
        #echo "nginx已关闭，正在重启" >> check.log
        # 启动nginx
        /usr/sbin/nginx

        status=$(ps -C nginx --no-header|wc -l)
        #echo $status >> check.log
        # 再次判断
        if [ $status -eq 0 ];then
        #       echo "nginx已关闭，正在重启" >> check.log
                # 关闭keepalived
                systemctl stop keepalived;
        fi
fi

创建keepalived配置文件

# 备份原有keepalived.conf内容
mv keepalived.conf keepalived.conf_bk
vim keepalived.conf

global_defs {
   router_id LVS_Ha2
}

vrrp_script chk_mysql {
    script "/etc/keepalived/chk_nginx.sh"
    interval 2
}
vrrp_instance HA_1 {
        state BACKUP
        interface ens33
        virtual_router_id 80
        priority 80
        advert_int 2
        nopreempt
        authentication {
                auth_type PASS
                auth_pass 1111
        }
        virtual_ipaddress {
          192.168.166.130
        }
        track_script {
        chk_mysql
        }
}