I’m looking into hosting a standard Java web app on AWS and the new Elastic Beanstalk (http://aws.amazon.com/elasticbeanstalk/) seems to have most of what we want. The one thing I can’t figure out is how to do distributed caching. It seems that AWS doesn’t allow multicast discovery of new nodes, so I’m not sure how new nodes started by the auto-scaling process should be integrated into an existing distributed cache. Any suggestions / best practices appreciated.

Update: Ideally this would be a cache local to each application server instance. Best case scenario would be a hibernate level 2 cache config for something like ehcache or terracota.

Another route to go down today (after 2011-08-23) is to use Amazon ElastiCache which is protocol-compliant with Memcached and runs in the cloud for you. Makes it easy to put things into an in-memory cache.