Akemi

Tomcat综合案例

2024/08/23

环境说明

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CentOS Linux release 7.9.2009 (Core)
jdk1.8.0-u421
tomcat 9.0.43
nignx 1.18
mysql 5.7.44 主从复制

主机地址
192.168.10.125 mysql-1
192.168.10.161 web1
192.168.10.162 web2
192.168.10.163 web3
192.168.10.164 nginx1
192.168.10.165 nginx2
vip 192.168.10.51/24

tomcat常用作java容器，擅长处理动态请求，但无法抗高并发
nginx擅长处理静态请求，并且可以处理高并发，可以做反向代理
两种整合方式：
1.动静分离：
将静态界面交给nginx，动态请求交给后端tomcat。只能针对非高并发的场景
2.负载均衡：
通过nginx反向代理和负载均衡，转发给后端tomcat
实际场景中，会使用cdn（比如cloudflare）来缓存静态资源，如果没有再访问源站服务器

NFS服务器准备

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mkdir -p /root/data/jdk1.8
echo "/root/data/jdk1.8/ 192.168.10.0/24(rw,sync,no_root_squash,no_subtree_check)" >> /etc/exports
echo "/root/data/tomcat/ 192.168.10.0/24(rw,sync,no_root_squash,no_subtree_check)" >> /etc/exports

#下载jdk包与tomcat包
tar -xf jdk-8u421-linux-x64.tar.gz
cp jdk1.8.0_421/* /root/data/jdk1.8/
chmod -R 777 /root/data/

wget https://dlcdn.apache.org/tomcat/tomcat-9/v9.0.93/bin/apache-tomcat-9.0.93.tar.gz
tar -xf apache-tomcat-9.0.93.tar.gz
cp -R apache-tomcat-9.0.93 /root/data/tomcat
mkdir /root/data/tomcat/tomcat-apps/ROOT
cp jpress-web-newest.war /root/data/tomcat/tomcat-apps/jpress.war

#修改conf/server.xml
vim /root/data/tomcat/conf/server.xml
<Server port="8001" shutdown="SHUTDOWN">
...
    <Connector port="8081" protocol="HTTP/1.1"
               connectionTimeout="20000"
               redirectPort="8443"
               maxParameterCount="1000"
...
      <Host name="www.it2.com"  appBase="tomcat-apps"
            unpackWARs="true" autoDeploy="true">

chmod -R 777 /root/data
exportfs -arv
#exporting 192.168.10.0/24:/root/data/tomcat
#exporting 192.168.10.0/24:/root/data/jdk1.8

数据库部分

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create database jpress;
CREATE USER 'jpress'@'%' IDENTIFIED BY '123456';
GRANT ALL PRIVILEGES ON jpress.* TO 'jpress'@'%';
FLUSH PRIVILEGES;

web服务器准备

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每台web服务器，先做其中一台
yum -y install nfs-utils
mkdir /usr/local/jdk1.8
mkdir /usr/local/tomcat
mount -t nfs 192.168.10.102:/root/data/jdk1.8 /usr/local/jdk1.8/
mount -t nfs 192.168.10.102:/root/data/tomcat /usr/local/tomcat
echo 'export JAVA_HOME=/usr/local/jdk1.8' >> /etc/profile
source /etc/profile 

#启动
/usr/local/tomcat/bin/startup.sh

#网页安装
http://www.it2.com:8081/jpress/install

#安装完成后为web2 web3进行挂载
yum -y install nfs-utils
mkdir /usr/local/jdk1.8
mkdir /usr/local/tomcat
mount -t nfs 192.168.10.102:/root/data/jdk1.8 /usr/local/jdk1.8/
mount -t nfs 192.168.10.102:/root/data/tomcat /usr/local/tomcat
echo 'export JAVA_HOME=/usr/local/jdk1.8' >> /etc/profile
source /etc/profile 
/usr/local/tomcat/bin/shutdown.sh
/usr/local/tomcat/bin/startup.sh

nginx负载均衡

主配置文件

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cat > /usr/local/nginx/conf/nginx.conf << 'EOF'
worker_processes  1;
events {
    worker_connections  1024;
}
http {
    include       /usr/local/nginx/conf/vhost/*.conf;
    include       mime.types;
    default_type  application/octet-stream;
    sendfile        on;
    keepalive_timeout  65;
}
EOF

子配置文件

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mkdir -p /usr/local/nginx/conf/vhost

将原本用户nginx的负载均衡配置改为备用
mv /usr/local/nginx/conf/vhost/nginx-LB.conf /usr/local/nginx/conf/vhost/nginx-LB.conf.bak

cat > /usr/local/nginx/conf/vhost/tomcat-LB.conf << 'EOF'
upstream java {
server 192.168.10.161:8081 weight=3 max_fails=3 fail_timeout=20s;
server 192.168.10.162:8081 weight=3 max_fails=3 fail_timeout=20s;
server 192.168.10.163:8081 weight=3 max_fails=3 fail_timeout=20s;
}
server {
	listen 80;
	server_name www.it.com;
	location / {
	  proxy_pass http://java;
	  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_set_header X-Forwarded-Proto $scheme;
	}
}
EOF
#先把keepalived关了，不然会一直自动拉活
systemctl stop keepalived.service
pkill nginx
nginx -t
nginx -s reload
nginx

curl 192.168.10.164:80/jpress/ > /dev/null 2>&1
echo $?
#0
#可以正常访问，就不放图了

scp -r /usr/local/nginx/conf nginx2:/usr/local/nginx/conf
chown -R www.www /usr/local/nginx

nginx集成keepalived

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#将原本的文件备份，再创建一个新的配置文件
nginx1主：
mv /etc/keepalived/keepalived.conf /etc/keepalived/nginx-keepalived.conf.bak
cat > /etc/keepalived/keepalived.conf << 'EOF'
! Configuration File for keepalived
global_defs {
        router_id lb01
}
vrrp_script check_nginx {
    script "/etc/keepalived/check_nginx.sh"
	  interval 5
}
vrrp_instance it {
    state MASTER
    interface ens18
    virtual_router_id 51
    priority 150
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.10.51/24
    }
    track_script {
        check_nginx
    }
}
EOF

nginx2备：
mv /etc/keepalived/keepalived.conf /etc/keepalived/nginx-keepalived.conf.bak
cat > /etc/keepalived/keepalived.conf << 'EOF'
! Configuration File for keepalived
global_defs {
        router_id lb02
}
vrrp_script check_nginx {
    script "/etc/keepalived/check_nginx.sh"
    interval 5
}
vrrp_instance it {
    state SLAVE
    interface ens18
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.10.51/24
    }
    track_script {
        check_nginx
    }
}
EOF

检测脚本

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cat > /etc/keepalived/check_nginx.sh <<'EOF'
#!/bin/bash
counter=$(ps -ef |grep nginx | grep sbin | egrep -cv "grep|$$" )
if [ $counter -eq 0 ]; then
    nginx
    echo "${date +%F} nginx重启" >> /etc/keepalived/check.log
    sleep 2
		counter=$(ps -ef |grep nginx | grep sbin | egrep -cv "grep|$$" )
    if [ $counter -eq 0 ]; then
        systemctl stop keepalived
        echo "$(hostname)主机nginx服务异常，vip已切换" | mail -s "keepalived告警" alertwarning@163.com
    fi
fi
ip a | grep -q 192.168.10.51
if [ $? -eq 0 ];then
		ssh nginx1 "ip a | grep -q 192.168.10.51"
		if [ $? -eq 0 ];then
		echo "${date +%F} 脑裂" >> /etc/keepalived/check.log
		echo "出现脑裂" | mail -s "keepalived脑裂警告" alertwarning@163.com
		fi
fi
EOF
systemctl daemon-reload
systemctl restart keepalived.service

keepalive拉活nginx测试

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ps -ef | grep -c nginx
#5
pkill nginx
ps -ef | grep -c nginx
#5

keepalived vip漂移测试

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#查看现在状态
主：
ip a | grep ens18 -A 10 | grep -w inet
#    inet 192.168.10.164/24 brd 192.168.10.255 scope global noprefixroute ens18
#    inet 192.168.10.51/24 scope global secondary ens18
备：
ip a | grep ens18 -A 10 | grep -w inet
#    inet 192.168.10.165/24 brd 192.168.10.255 scope global noprefixroute ens18

#关闭主节点的keepalived
systemctl stop keepalived.service

#此时查看状态
主：
ip a | grep ens18 -A 10 | grep -w inet
#    inet 192.168.10.164/24 brd 192.168.10.255 scope global noprefixroute ens18
备：
ip a | grep ens18 -A 10 | grep -w inet
#    inet 192.168.10.165/24 brd 192.168.10.255 scope global noprefixroute ens18
#    inet 192.168.10.51/24 scope global secondary ens18

keepalive相关故障总结(搬运)

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日志查看地址：/var/log/messages

日志问题与解决方案
1. 日志提示：
WARNING - script '/etc/keepalived/check_nginx.sh' is not executable for uid:gid 0:0 - disabling.
原因：keepalived监控脚本没有执行权限。
解决：
chmod +x /etc/keepalived/check_nginx.sh

2. 日志提示：
/etc/keepalived/check_nginx.sh exited due to signal 15
解决：
# 调整脚本执行间隔  
interval 5  
# 心跳检查间隔时间  
advert_int 1
注意：确保监控脚本的执行时间大于advert_int的值。

3. 日志提示：
Error exec-ing command ‘/etc/keepalived/nginx_check.sh’, error 2: No such file or directory
原因：脚本文件可能不存在或路径错误，或者脚本文件格式不正确。
解决：
使用vi创建并编辑脚本：
vi nginx_check.sh
脚本编写完成后，使用sh命令测试执行：

sh nginx_check.sh
若执行报错（如语法错误），检查并修改脚本内容。
使用vim检查并修改脚本文件格式：

vim nginx_check.sh  
:set ff?  # 查看当前文件格式  
:set ff=unix  # 设置为UNIX格式  
# 或者  
:set fileformat=unix

4. 问题描述：
如果MASTER关闭，但是BACKUP没有抢占VIP，可能是防火墙阻挡了VRRP广播。
解决：
在iptables中添加规则以允许VRRP广播：
iptables -A INPUT -p vrrp -j ACCEPT

原文作者：王盛

原文链接：https://akemi.zj.cn/2024/08/23/Tomcat-Project/

发表日期：August 23rd 2024, 1:01:30 am

更新日期：February 20th 2025, 6:37:27 pm

版权声明：本文采用知识共享署名-非商业性使用 4.0 国际许可协议进行许可

CATALOG
  1. 1. 环境说明
  2. 2. NFS服务器准备
  3. 3. web服务器准备
  4. 4. nginx负载均衡
  5. 5. nginx集成keepalived
  6. 6. keepalive相关故障总结(搬运)
Total : 203
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