nginx+redis+4个tomcat 负载均衡

1，先配置nginx ，如果80接口被占用，且80 的端口又惹不起，参考：https://www.cnblogs.com/xiaohu1218/p/10267602.html

2，下载redis，并配置。、

3，下载tomcat ，两个tomcat8，两个tomcat9。并修改端口号（如不在同一个电脑，可以不用需改），我是同一个电脑，为了方便，标记如下：

 <h3>tomcatX:</h3>   // X 1，2，3，4

<% HttpSession session = request.getSession(); %>

<%= session.getId() %>

4，修改tomcat中%Home%\conf 中context.xml  ,加入

   <Manager className="tomcat.request.session.redis.SessionManager"
         host="localhost"
         port=""
         database=""
         maxInactiveInterval="" />

5，将 这四个jar包，加入到%home%lib中，

. jedis.jar
. commons-pool2.jar
. commons-logging.jar
.tomcat-cluster-redis-session-manager.jar

或者：

. Move the downloaded jars to tomcat/lib directory
        * tomcat/lib/

    . Add tomcat system property "catalina.base"
        * catalina.base="TOMCAT_LOCATION"

    . Extract downloaded package (tomcat-cluster-redis-session-manager.zip) to configure Redis credentials in redis-data-cache.properties file and move the file to tomcat/conf directory
        * tomcat/conf/redis-data-cache.properties

    . Add the below two lines in tomcat/conf/context.xml
        <Valve className="tomcat.request.session.redis.SessionHandlerValve" />
        <Manager className="tomcat.request.session.redis.SessionManager" />

    . Verify the session expiration time (minutes) in tomcat/conf/web.xml
        <session-config>
            <session-timeout><session-timeout>
        <session-config>

配置redis-data-cache.properties

#-- Redis data-cache configuration

#- redis hosts ex: 
redis.hosts=127.0.0.1:6379

#- redis password (for stand-alone mode)
#redis.password=

#- set true to enable redis cluster mode
redis.cluster.enabled=false

#- redis database (default 0)
redis.database=0

#- redis connection timeout (default 2000)
redis.timeout=2000

6，启动四个tomcat

7，修改niginx中的config/nginx.conf，

加入

    #服务器集群
    upstream  localhost {
          server   localhost:  weight=;
      server   localhost:  weight=;
      server   localhost:  weight=;
      server   localhost:  weight=;
      }
    server {
        listen       ;
        server_name  localhost;

        #charset koi8-r;

        #access_log  logs/host.access.log  main;

        location / {
      proxy_pass  http://localhost;
            root   html;
            index  index.html index.htm;
        }

8，启动nginx，即可。