Arrowchat and Amazon instances
You need to use ElasticCache and share the Node pool among all the instances of the autoscale group. If the templates need processing you can't use amazon S3 directly. (The php code on a specific instance HAS to read the template, process it and send it back). Pseudocode:Associate a unique Key to each template (i.e. data/template_name ).When a template is requested, check on Memcache if there is such Key.Otherwise read it from S3 and load it in the cache. Once is in the cache all the instances will be able to use that single value.