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  • 分布式下Session一致性架构举例

    一、问题及方案

    见这篇文章:分布式下Session一致性问题

    二、分布式环境搭建:

    系统环境

    [root@centos7 ~]# cat /etc/redhat-release 
    CentOS Linux release 7.4.1708 (Core) 
    [root@centos7 ~]# 
    

    2.1 安装jdk

    # 下载jdk-8u141-linux-x64.tar.gz
    # 创建目录
    mkdir -p /opt/java
    # 解压
    tar -xzvf jdk-8u141-linux-x64.tar.gz -C /opt/java
    # 创建链接
    ln -s /opt/java/jdk1.8.0_141 /usr/local/jdk
    # 设置变量 /etc/profile末尾添加
    export JAVA_HOME=/usr/local/jdk
    export CLASSPATH=.:$JAVA_HOME/jre/lib/rt.jar:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
    # 使变量生效
    source /etc/profile
    export PATH=$JAVA_HOME/bin:$PATH
    # 验证
    java -version
    

    2.2 安装tomcat

    安装3个tomcat并设置其端口号

    # 下载apache-tomcat-8.5.16.tar.gz
    # 创建目录
    mkdir -p /opt/tomcat
    # 解压
    tar -xzvf apache-tomcat-8.5.16.tar.gz -C /opt/tomcat
    # 清空ROOT目录
    rm -rf /opt/tomcat/apache-tomcat-8.5.16/webapps/ROOT/*
    # 复制3个tomcat
    cd /opt/tomcat
    cp -a apache-tomcat-8.5.16 tomcat1
    cp -a apache-tomcat-8.5.16 tomcat2
    cp -a apache-tomcat-8.5.16 tomcat3
    # 修改端口号
    sed -i '22s/8005/8'"$i"'05/' $file
    sed -i '69s/8080/8'"$i"'80/' $file
    sed -i '116s/8009/8'"$i"'09/' $file
    

    修改如下3个端口号

    用如下脚本修改:a.sh

    #!/bin/sh
    
    for i in {1..3}
    do
      file=/opt/tomcat/tomcat"$i"/conf/server.xml
      sed -i '22s/8005/8'"$i"'05/' $file
      sed -i '69s/8080/8'"$i"'80/' $file
      sed -i '116s/8009/8'"$i"'09/' $file
      #sed -i '148s#appBase=".*"#appBase="/data/webapps"#' $file
    done
    

    执行脚本修改端口

    sh a.sh
    执行后,3个tomcat的端口号分别改为
    8180,8280,8380
    

    启动并验证这3个tomcat

    # 分别向3个tomcat写入一个测试文件a.txt
    for i in {1..3};do echo 8"$i"80>/opt/tomcat/tomcat"$i"/webapps/ROOT/a.txt;done
    
    # 启动
    for i in {1..3};do /opt/tomcat/tomcat"$i"/bin/startup.sh;done
    
    # 验证
    for i in {1..3};do curl 127.0.0.1:8"$i"80/a.txt;done
    

    2.3 安装nginx

    # 下载nginx-1.13.9.tar.gz
    mkdir -p /opt/nginx/nginx-1.3.13.9
    # 创建用户
    useradd nginx -s /sbin/nologin -M
    # 安装pcre openssl
    yum install pcre pcre-devel openssl openssl-devel -y
    # 解压、编译安装
    tar -xzvf nginx-1.13.9.tar.gz
    cd nginx-1.13.9
    ./configure --user=nginx --group=nginx --prefix=/opt/nginx/nginx-1.13.9 --with-http_stub_status_module --with-http_ssl_module
    make
    make install
    # 创建链接
    ln -s /opt/nginx/nginx-1.13.9 /usr/local/nginx
    # 设置环境变量
    echo 'export PATH=/usr/local/nginx/sbin:$PATH' >> /etc/profile
    source /etc/profile
    

    nginx常用命令

    # 启动
    nginx
    # 检查配置文件
    nginx -t
    # 平滑启动
    nginx -s reload
    # 检查
    netstat -tunlp | grep nginx
    

    遇到的问题:

    nginx: [emerg] getpwnam("nginx") failed
    未创建nginx用户
    

    配置nginx

    /usr/local/nginx/conf/nginx.conf

    worker_processes  1;
    events {
        worker_connections  1024;
    }
    
    # http最外层模块
    http {
    	# 全局变量参数
        include       mime.types;
        default_type  application/octet-stream;
        sendfile        on;
        keepalive_timeout  65;
    
    	upstream web_pool {
    		server 127.0.0.1:8180 weight=1;
    		server 127.0.0.1:8280 weight=1;
    		server 127.0.0.1:8380 weight=2;
    	}
    
    	# server相当于虚拟站点
        server {
            listen       80;
            server_name  localhost;
            location / {
                proxy_pass  http://web_pool;
                index  index.html index.htm;
            }
        }
    }
    

    测试一下

    for i in {1..9};do curl 127.0.0.1/a.txt;done
    

    2.4 安装redis

    wget http://download.redis.io/releases/redis-4.0.8.tar.gz
    mkdir -p /opt/redis
    tar -xzvf redis-4.0.8.tar.gz -C /opt/redis/
    ln -s /opt/redis/redis-4.0.8 /usr/local/redis
    cd /usr/local/redis
    make && make install
    
    # 配置让其他机器也可以访问
    vi /usr/local/redis/redis.conf
    #bind 127.0.0.1
    bind 0.0.0.0
    

    操作redis

    # 查看redis版本
    redis-cli -v
    # 启动redis
    redis-server redis.conf > /tmp/redis.log 2>&1 &
    # or
    nohup redis-server redis.conf &
    # 监控redis
    redis-cli -h 192.168.234.130 -p 6379 monitor
    # 关闭redis
    redis-cli -h 127.0.0.1 -p 6379 shutdown
    

    客户端

    # 连接
    redis-cli -h 192.168.5.220
    # 查看
    keys *
    # 清空
    flushall
    

    三、问题重现

    3.1 web应用

    java-web-login

    只实现登录功能

    /login   登录页面,已登录跳转到/index
    /logout  退出
    /index   首页,未登录跳转到/login
    

    将这个应用部署到3个tomcat上

    重启tomcat

    for i in {1..3};do /opt/tomcat/tomcat"$i"/bin/shutdown.sh;done
    for i in {1..3};do /opt/tomcat/tomcat"$i"/bin/startup.sh;done
    

    3.2 问题描述

    登录界面是8280端口,输入用户名密码点击登录,由于nginx配置的是基于轮询的算法进行分发,8380端口的服务器处理的登录,因此session创建于8380端口,而8280处于非登录状态。

    四、解决实现

    4.1 session sticky

    修改nginx的分发算法改为基于ip

    upstream web_pool {
    	# 默认是轮询
    	ip_hash;
    	server 127.0.0.1:8180 weight=1;
    	server 127.0.0.1:8280 weight=1;
    	server 127.0.0.1:8380 weight=2;
    }
    

    修改后重启nginx

    nginx -t
    nginx -s reload
    

    4.2 session replication

    http://tomcat.apache.org/tomcat-8.5-doc/cluster-howto.html

    tomcat配置server.xml

    <!--修改每个tomcat下的conf/server.xml-->
    <!--其中Receiver这个结点的端口分别配置为4001,4002,4003-->
    <!--channelSendOptions-->
    <!--8表示异步发送 2表示确认发送 4表示同步发送 10表示同步+确认-->
    <Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster" 
    	channelSendOptions="8">
    	<Manager className="org.apache.catalina.ha.session.DeltaManager" 
    		expireSessionsOnShutdown="false" 
    		notifyListenersOnReplication="true" />
    	<Channel className="org.apache.catalina.tribes.group.GroupChannel">
    		<!-- 228.0.0.4是主播地址-->
    		<Membership className="org.apache.catalina.tribes.membership.McastService"
    			address="228.0.0.4" 
    			port="45564" 
    			frequency="500" 
    			dropTime="3000" />
    		<Receiver className="org.apache.catalina.tribes.transport.nio.NioReceiver"
    			address="auto" 
    			port="4001" 
    			autoBind="100" 
    			selectorTimeout="5000"
    			maxThreads="6" />
    		<Sender className="org.apache.catalina.tribes.transport.ReplicationTransmitter">
    			<Transport className="org.apache.catalina.tribes.transport.nio.PooledParallelSender" />
    		</Sender>
    		<Interceptor className="org.apache.catalina.tribes.group.interceptors.TcpFailureDetector" />
    		<Interceptor className="org.apache.catalina.tribes.group.interceptors.MessageDispatchInterceptor" />
    	</Channel>
    	<Valve className="org.apache.catalina.ha.tcp.ReplicationValve" filter="" />
    	<Valve className="org.apache.catalina.ha.session.JvmRouteBinderValve" />
    	<Deployer className="org.apache.catalina.ha.deploy.FarmWarDeployer"
    		tempDir="/tmp/war-temp/" 
    		deployDir="/tmp/war-deploy/" 
    		watchDir="/tmp/war-listen/"
    		watchEnabled="false" />
    	<ClusterListener className="org.apache.catalina.ha.session.ClusterSessionListener" />
    </Cluster>
    

    tomcat的配置web.xml

    # 修改每个tomcat下的conf/web.xml不起作用
    # 一定要修改每个应用的web.xml,在<web-app>这个节点下添加
    <distributable />
    

    4.3 session数据集中存储

    数据存储到redis,使用spring-data-redis

    见应用java-web-login

    把web_spring-redis.xml重命名为web.xml,部署到tomcat即可,得先启动redis参照“安装redis”这一节。

    spring-redis.xml

    	<?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans"
    	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
    	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
           http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
    
    	<!-- 引入配置文件 -->
    	<bean id="propertyConfigurer"
    		class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    		<property name="locations">
    			<list>
    				<value>classpath*:redis.properties</value>
    			</list>
    		</property>
    	</bean>
    
    	<bean id="redisHttpSessionConfiguration"
    		class="org.springframework.session.data.redis.config.annotation.web.http.RedisHttpSessionConfiguration">
    		<property name="maxInactiveIntervalInSeconds" value="600"/>
    	</bean>
    
    	<bean id="jedisPoolConfig" class="redis.clients.jedis.JedisPoolConfig">
    		<property name="maxTotal" value="${redis.pool.maxTotal}" />
    		<property name="maxIdle" value="${redis.pool.maxIdle}" />
    	</bean>
    
    	<bean id="jedisConnectionFactory"
    		class="org.springframework.data.redis.connection.jedis.JedisConnectionFactory"
    		destroy-method="destroy">
    		<property name="hostName" value="${redis.hostname}" />
    		<property name="port" value="${redis.port}" />
    		<property name="timeout" value="${redis.timeout}" />
    		<property name="usePool" value="true" />
    		<property name="poolConfig" ref="jedisPoolConfig" />
    	</bean>
    </beans>
    

    注意:

    • Spring版本的选择 >=4.0.3

    pom.xml

    <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    	<modelVersion>4.0.0</modelVersion>
    	<groupId>com.yysue</groupId>
    	<artifactId>java-web-login</artifactId>
    	<packaging>war</packaging>
    	<name>java-web-login</name>
    	<version>0.0.1-SNAPSHOT</version>
    
    	<properties>
    		<java.version>1.8</java.version>
    		<spring.version>4.0.3.RELEASE</spring.version>
    	</properties>
    
    	<!-- 依赖 -->
    	<dependencies>
    		<dependency>
    			<groupId>javax.servlet</groupId>
    			<artifactId>javax.servlet-api</artifactId>
    			<version>3.0.1</version>
    			<scope>provided</scope>
    		</dependency>
    
    		<dependency>
    			<groupId>javax.servlet.jsp</groupId>
    			<artifactId>jsp-api</artifactId>
    			<version>2.2</version>
    			<scope>provided</scope>
    		</dependency>
    
    		<dependency>
    			<groupId>javax.servlet</groupId>
    			<artifactId>jstl</artifactId>
    			<version>1.2</version>
    		</dependency>
    
    		<dependency>
    			<groupId>org.springframework</groupId>
    			<artifactId>spring-core</artifactId>
    			<version>${spring.version}</version>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework</groupId>
    			<artifactId>spring-web</artifactId>
    			<version>${spring.version}</version>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework</groupId>
    			<artifactId>spring-oxm</artifactId>
    			<version>${spring.version}</version>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework</groupId>
    			<artifactId>spring-tx</artifactId>
    			<version>${spring.version}</version>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework</groupId>
    			<artifactId>spring-webmvc</artifactId>
    			<version>${spring.version}</version>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework</groupId>
    			<artifactId>spring-context</artifactId>
    			<version>${spring.version}</version>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework</groupId>
    			<artifactId>spring-context-support</artifactId>
    			<version>${spring.version}</version>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework</groupId>
    			<artifactId>spring-aop</artifactId>
    			<version>${spring.version}</version>
    		</dependency>
    
    		<dependency>
    			<groupId>org.springframework.data</groupId>
    			<artifactId>spring-data-redis</artifactId>
    			<version>1.5.2.RELEASE</version>
    		</dependency>
    
    		<dependency>
    			<groupId>org.springframework.session</groupId>
    			<artifactId>spring-session-data-redis</artifactId>
    			<version>1.2.2.RELEASE</version>
    		</dependency>
    
    		<dependency>
    			<groupId>redis.clients</groupId>
    			<artifactId>jedis</artifactId>
    			<version>2.8.1</version>
    		</dependency>
    
    	</dependencies>
    
    	<build>
    		<!-- 插件 -->
    		<plugins>
    			<plugin>
    				<groupId>org.apache.maven.plugins</groupId>
    				<artifactId>maven-compiler-plugin</artifactId>
    				<configuration>
    					<source>${java.version}</source>
    					<target>${java.version}</target>
    				</configuration>
    			</plugin>
    		</plugins>
    	</build>
    </project>
    
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  • 原文地址:https://www.cnblogs.com/okokabcd/p/8543004.html
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