tomcat 之 httpd session stiky

# 注释中心主机

[root@nginx ~]# vim /etc/httpd/conf/httpd.conf
#DocumentRoot "/var/www/html"

#：配置虚拟主机

[root@nginx ~]# vim /etc/httpd/conf.d/tomcat.conf
<VirtualHost *:80>
ServerName      node1.magedu.com
ProxyRequests   Off
ProxyVia        On
ProxyPreserveHost On
ProxyPass       / balancer://lbtomcats/
ProxyPassReverse / balancer://lbtomcats/
</VirtualHost>

<Proxy balancer://lbtomcats>
BalancerMember http://node1.magedu.com:8080 loadfactor=1
BalancerMember http://node2.magedu.com:8080 loadfactor=2
</Proxy>

#：分别配置tomcat
[root@node1 ~]# vim /usr/local/tomcat/conf/server.xml
<Engine name="Catalina" defaultHost="node1.magedu.com" jvmRoute="Tomcat1">
[root@node2 ~]# vim /usr/local/tomcat/conf/server.xml
<Engine name="Catalina" defaultHost="node2.magedu.com" jvmRoute="Tomcat2">

#观察结果是轮询的

#：使用session粘性

[root@nginx ~]# vim /etc/httpd/conf.d/tomcat.conf
Header add Set-Cookie "ROUTEID=.%{BALANCER_WORKER_ROUTE}e; path=/" env=BALANCER_ROUTE_CHANGED
<VirtualHost *:80>
ServerName      node1.magedu.com
ProxyRequests   Off
ProxyVia        On
ProxyPreserveHost On
ProxyPass       / balancer://lbtomcats/
ProxyPassReverse / balancer://lbtomcats/
</VirtualHost>

<Proxy balancer://lbtomcats>
BalancerMember http://node1.magedu.com:8080 loadfactor=1 route=Tomcat1
BalancerMember http://node2.magedu.com:8080 loadfactor=2 route=Tomcat2
ProxySet stickysession=ROUTEID
</Proxy>
#
发现Session不变了，一直找的同一个Tomcat服务器

#：api

[root@nginx ~]# vim /etc/httpd/conf.d/tomcat.conf
<VirtualHost *:80>
ServerName      node1.magedu.com
ProxyRequests   Off
ProxyVia        On
ProxyPreserveHost On
ProxyPass       / balancer://lbtomcats/
ProxyPassReverse / balancer://lbtomcats/
</VirtualHost>

<Proxy balancer://lbtomcats>
BalancerMember ajp://node1.magedu.com:8009 loadfactor=1 route=Tomcat1
BalancerMember ajp://node2.magedu.com:8009 loadfactor=2 route=Tomcat2
ProxySet stickysession=ROUTEID
</Proxy>

虽然，上面的做法实现客户端在一段时间内找同一台Tomcat，从而避免切换后导致的Session丢失。但是如果

Tomcat节点挂掉，那么Session依旧丢失。

假设有A、B两个节点，都将Session持久化。如果Tomcat A服务下线期间用户切换到了Tomcat B上，就获得了Tomcat B的Session，就算持久化Session的Tomcat A上线了，也没用了。