What are the strategies you might use to update an application running on multiple Tomcat instances (clustered with Apache mod_jk) with a seamless transition for somebody who's using the application at the time the application is redeployed? I've always wondered how web applications that cannot afford downtime do it.
In my naive understanding I'd simply shut off all servers, redeploy the updated applications, then turn all the servers back on. In this case, it's pretty straightforward to understand what would happen. However, users would experience downtime (or at least a non-seamless transition). In environments that have requirements not to make users relogin everytime a change is made, how would applications that provide smaller, more frequent updates survive? How would you go about doing this, specifically, in a clustered Tomcat environment? What things should I keep in mind when figuring out how to best do this? Problems that I foresee include someone who's POSTing from his current page to a just-updated version of a servlet on Tomcat...in this case, what the user expects to happen might not be what is expected, due to the servlet update. In the best case the user has to relogin due to an error. In the worst case the operation goes through successfully but modifies the data in some unexpected way. Your insight on this matter is greatly appreciated. -- View this message in context: http://www.nabble.com/Seamless-transition-between-application-updates-tf3649567.html#a10194118 Sent from the Tomcat - User mailing list archive at Nabble.com. --------------------------------------------------------------------- To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
