在web之外定义一个。xml(如服务器范围)

I would like to apply security constraints for all webapps deployed on a Tomcat7 server. To do this I have set up a Realm and Valve. My understanding is that the contents of context.xml get included for all apps deployed to a server - that part seems to work as I can add all manner of configuration and I see the effects as it gets included in the various deployed app contexts. It works wonderfully for enforcing consistency across web apps.I would like to apply security constraints for