Tomcat会话保持方式实现与MSM配置实例

Tomcat会话保持方式

(1). session sticky：简单的基于会话保持机制，在调度器上实现；

• source_ip:源地址绑定
  • nginx: ip_hash
  • haproxy: source
  • lvs: sh
• cookie：基于cookie绑定
  • nginx：hash
  • haproxy: cookie

(2). session cluster：delta session manager ；是tomcat自带的会话集群；在调度器上不需要做会话绑定；
(3). session server：redis(store), memcached(cache)；使用memcached构建session server；跟前端调度器没关系，tomcat要能调用后端的某个服务器的API完成会话数据存取；

注：此处基于前文中的LNAMT环境演示中配置的两台tomcat主机作为后端主机实验

1. 基于session sticky方式：

第一种方式实现：：mod_proxy_http模块，并基于cookie实现会话粘性

session-sticky1.png

  编辑http的配置文件：
  [root@localhost ~]# vim /etc/httpd/conf.d/mod_proxy_http.conf
      内容如下：
      Header add Set-Cookie "ROUTEID=.%{BALANCER_WORKER_ROUTE}e; path=/" env=BALANCER_ROUTE_CHANGED
    
        BalancerMember http://192.168.43.15:8080 route=tomcatA loadfactor=1
        BalancerMember http://192.168.43.16:8080 route=tomcatB loadfactor=2
        ProxySet lbmethod=byrequests
        ProxySet stickysession=ROUTEID
    
    
    
        ServerName www.inux.com
        ProxyVia ON
        ProxyRequests Off
        ProxyPreserveHost ON
        
            Require all granted
        
        ProxyPass / balancer://tcsrvs/
        ProxyPassReverse / balancer://tcsrvs/
        
            Require all granted
        
    
[root@localhost ~]# httpd -t
Syntax OK
[root@localhost ~]# systemctl reload httpd.service

浏览器访问测试：

session-sticky2.png

在httpd中的mod_proxy_balancer模块，自带有管理页面：

在上文http配置文件中添加一个管理页面的location
[root@localhost ~]# vim /etc/httpd/conf.d/mod_proxy_http.conf
    
        SetHandler balancer-manager
        ProxyPass !
        Require all granted
    
[root@localhost ~]# httpd -t
[root@localhost ~]# systemctl reload httpd.service

浏览器输入：http://192.168.43.12/balancer-manager

balancer-manager.png

第二种方式实现：mod_proxy_ajp模块

session-sticky3.png

[root@localhost ~]# httpd -M | grep "ajp" 
 proxy_ajp_module (shared)  确保mod_proxy_ajp模块加载并启用  
[root@localhost ~]# mv /etc/httpd/conf.d/mod_proxy_http.conf  /etc/httpd/conf.d/mod_proxy_http.conf.bak
[root@localhost ~]# vim /etc/httpd/conf.d/mod_proxy_ajp.conf
编辑内容如下： 
    
            BalancerMember ajp://192.168.43.15:8009
            BalancerMember ajp://192.168.43.16:8009
            ProxySet lbmethod=byrequests
    
    
    
            ServerName www.inux.com
            ProxyVia On
            ProxyRequests Off
            ProxyPreserveHost On
            
                    Require all granted
            
            ProxyPass / balancer://tcsrvs/
            ProxyPassReverse / balancer://tcsrvs/
            
                    Require all granted
            
            
                    SetHandler balancer-manager
                    ProxyPass !
                    Require all granted
            
    
[root@localhost ~]# httpd -t
[root@localhost ~]# systemctl restart httpd.service

使用浏览器访问可是实现轮询访问后端tomcat主机

第三种方式实现：nginx+tomcat

session-sticky4.png

<1> 源地址绑定：

修改nginx.conf配置文件中upstream上下文中：
[root@localhost ~]# vim /usr/local/nginx/conf/conf.d/proxy_nginx.conf
    upstream websrvs {
      server 192.168.43.15:8080 ;
      server 192.168.43.16:8080 ;
      server 127.0.0.1:80 backup;
      ip_hash;
      }
    server {
    listen 80;
    server_name www.ilinux.io;
    index index.html index.jsp;
    location / {
                proxy_pass http://websrvs;
            }
        }


 <2>基于cookie绑定：
 [root@localhost ~]# vim /usr/local/nginx/conf/conf.d/proxy_nginx.conf
     upstream websrvs {
      server 192.168.43.15:8080 ;
      server 192.168.43.16:8080 ;
      server 127.0.0.1:80 backup;
      hash srv_id;
      }
    server {
    listen 80;
    server_name www.ilinux.io;
    index index.html index.jsp;
    location / {
                proxy_pass http://websrvs;
            }
        }
[root@localhost ~]# nginx -t
nginx: the configuration file /usr/local/nginx/conf/nginx.conf syntax is ok
nginx: configuration file /usr/local/nginx/conf/nginx.conf test is successful
[root@localhost ~]# nginx -s reload

注意：使用session sticky做会话保持，缺陷是损坏负载均衡效果，某一主机掉线其上的会话也会丢失，这种方法实际中并不使用；真正用时，可使用会话集群或会话服务器来做会话绑定；

2. Tomcat Session Replication Cluster

tomcat-Cluster.png

(1) 配置启用集群，将下列配置放置于server.xml配置文件的或段中；（注：此处为tomcat-8.5.34,版本，配置文件与之前版本略有不同）

   #请确认此处jvmRoute名称与前代worker名称保持一致；
       
     
                
                
                
                

                
                
                
                
                
                

                

                
                
                

            
            

（2）配置webapps
编辑WEB-INF/web.xml，添加

[root@node6 ~]# systemctl stop tomcat.service 
[root@node6 ~]# cd /usr/local/tomcat
[root@node6 tomcat]# cp /usr/local/tomcat/conf/web.xml /usr/local/tomcat/webapps/test/WEB-INF/
[root@node6 tomcat]# vim /usr/local/tomcat/webapps/test/WEB-INF/web.xml
在文件中之前添加``

在另外一个tomcat主机上同样部署上两步即可
（3） 启动tomcat，查看日志

[root@node6 ~]# systemctl start tomcat.service
[root@node6 ~]# tail -200 /usr/local/tomcat/logs/catalina.2018-10-11.log 
...
11-Oct-2018 01:55:47.979 INFO [localhost-startStop-1] org.apache.catalina.ha.session.DeltaManager.getAllClusterSessions Manager [localhost#/test], requesting session state from [org.apache.catalina.tribes.membership.MemberImpl[tcp://{192, 168, 43, 15}:4000,{192, 168, 43, 15},4000, alive=15628, securePort=-1, UDP Port=-1, id={-94 23 -31 -98 -14 -48 67 -28 -91 -88 37 -65 11 99 96 66 }, payload={}, command={}, domain={}]]. This operation will timeout if no session state has been received within [60] seconds.
...

（4）在浏览器输入：http://192.168.43.11/test/
基于调度器后端不同主机，但会话保持不变；

tomcat-Cluster1.png

tomcat-Cluster2.png

3. session server： memcached-session-manager

memcached-session-manager项目地址：

http://code.google.com/p/memcached-session-manager/, https://github.com/magro/memcached-session-manager

memcached-msm.png

（1）在后端192.168.43.13和192.168.43.14两台主机上安装memcached

[root@localhost ~]# yum -y install memcached
[root@localhost ~]# rpm -ql memcached
/etc/sysconfig/memcached
/usr/bin/memcached
/usr/bin/memcached-tool
/usr/lib/systemd/system/memcached.service
/usr/share/doc/memcached-1.4.15
/usr/share/doc/memcached-1.4.15/AUTHORS
/usr/share/doc/memcached-1.4.15/CONTRIBUTORS
/usr/share/doc/memcached-1.4.15/COPYING
/usr/share/doc/memcached-1.4.15/ChangeLog
/usr/share/doc/memcached-1.4.15/NEWS
/usr/share/doc/memcached-1.4.15/README.md
/usr/share/doc/memcached-1.4.15/protocol.txt
/usr/share/doc/memcached-1.4.15/readme.txt
/usr/share/doc/memcached-1.4.15/threads.txt
/usr/share/man/man1/memcached-tool.1.gz
/usr/share/man/man1/memcached.1.gz
[root@localhost ~]# systemctl start memcached
[root@localhost ~]# ss -tnlp | grep memcached
LISTEN     0      128          *:11211                    *:*                   users:(("memcached",pid=17429,fd=26))
LISTEN     0      128         :::11211                   :::*                   users:(("memcached",pid=17429,fd=27))

（2）配置MSM
下载如下jar文件至各tomcat节点的tomcat安装目录下的lib目录中，

javolution-5.4.3.1.jar                   
msm-javolution-serializer-2.1.1.jar
memcached-session-manager-2.1.1.jar      
spymemcached-2.11.7.jar
memcached-session-manager-tc8-2.1.1.jar

分别在两个tomcat上的某host上定义一个用于测试的context容器，并在其中创建一个会话管理器，如下所示：

启动tomcat：

[root@node6 conf]# systemctl start tomcat

查看日志：

[root@node6 ~]# tail /usr/local/tomcat/logs/catalina.2018-10-13.log
...
    -  finished initialization:
    - sticky: true
    - operation timeout: 1000
    - node ids: [m1]
    - failover node ids: [m2]
    - storage key prefix: null

前端调度器上反代2个tomcat主机 配置如下：

server {
    listen 80;
    server_name www.ilinux.io;
    index index.html index.jsp;
    location / {
                proxy_pass http://websrvs;
            }
        }
upstream websrvs {
          server 192.168.43.15:8080;
          server 192.168.43.16:8080;
          server 127.0.0.1:80 backup;
             }

浏览器访问测试实现会话粘性：

session-server1.png

session-server2.png