Redeploy/Failover for Glassfish cluster on EC2?

I have a Tapestry application (WAR, no EJB) that ...

• ... I want to deploy on 2 EC2 small instances (for failover).
开发者_运维技巧
• ... uses Spring Security
• ... is stateful (very small session state)
• ... should be deployed on Glassfish 3.1 (seems to have best cluster support?)
• ... and has an elastic load balancer with sticky session in front of it

How can I configure a cluster to achieve minimal ('no') interruptions for the user experience in case A) a node fails and B) I deploy a new version?

Everything is explained here: http://download.oracle.com/docs/cd/E18930_01/html/821-2426/docinfo.html#scrolltoc

Basically, you setup a DAS (=master), which control nodes with instances on it. You could do all of this on the same machine (1 DAS, 1 node with multiple instances), although it would be a good idea to have at least 2.

You should then have at least one load balancer (apache, physical load balancer, whatever).

A) if a node fails, the load balancer can redirect all traffic to the other node

B)

• deploy application, disabled, with new version (see "application versioning")
• mark server A as unavailable
• enable the new version on server A
• mark server A as available and server B as unavailable
• enable the new version on server B
• mark server B as avalilable