Apache load-balancer: direct to specific application based on URL - apache

Question

I have multiple applications deployed in Tomcat's webapps folder (app1.0, app1.1, app1.2 etc.). When I hit www.example.com:8080/app1.0, the corresponding application appears.
But how to do it on the load-balancing server? For instance, I have a website on which I can click a button (app1.0, app1.1, app1.2 etc.) and an URL pops up like: www.lb.com/app1.0/.../... How to direct to the app based on application version in URL? Use RewriteCond and regex and pass it to ProxyPass? I don't really how to script it, anyone could help? :)
Edit: This is what I done for the 2 apps for 1 Tomcat and 2 apps for 2 Tomcat, but I got 404 sometimes because the Tomcat that has another version has been chosen by the load-balancer.
<VirtualHost *:80>
#Add a http header to explicitly identify the node and be sticky
Header add Set-Cookie "ROUTEID=.%{BALANCER_WORKER_ROUTE}e; path=/" env=BALANCER_ROUTE_CHANGED
#Declare the http server pool
<Proxy "balancer://plf">
BalancerMember "http://worker1.com:8080" route=worker1
BalancerMember "http://worker2.com:8080" route=worker2
ProxySet stickysession=ROUTEID
ProxySet lbmethod=bybusyness
</Proxy>
#Common options
ProxyRequests Off
ProxyPreserveHost On
#Declare the redirection for the http requests
ProxyPassMatch "/app(.*)" "balancer://plf/app$1"
ProxyPassReverse "/app(.*)" "balancer://plf/app$1"

Answer 1

This is how I did it:
1) define a balancer proxy:
<Proxy balancer://portalcluster stickysession=JSESSIONID>
BalancerMember ajp://TOMCATSERVER1:8009 route=TOMCARSERVER1-0
BalancerMember ajp://TOMCATSERVER2:8009 route=TOMCATSERVER2-100
</Proxy>
2) proxy to it in your VirtualHost:
Listen 443
<Virtualhost *:443>
ServerName example.com
Alias /static /var/www/portalstatic
ProxyPass /static !
ProxyPass / balancer://portalcluster/
ProxyPassReverse / balancer://portalcluster/
</Virtualhost>
NB I removed a lot of configuration from these, that are not related to the question (logs, deny clauses, certificate directives, ...). This is just to illustrate the way I did the proxy.
NB2 I did leave the /static trick since this is usually something you will want to do. Static files must stay on the HTTP, and not send them from Tomcat all the time.