Pretty neat. In my opinion if you've got several EC2 instances that have similar roles and you're looking to manage them in parallel, you should already be usin

Pretty neat. In my opinion if you've got several EC2 instances that have similar roles and you're looking to manage them in parallel, you should already be using a configuration management tool like Chef, and most of those tools have this sort of thing built in. For example, in addition to managing instances with Chef cookbooks, you can run arbitrary commands in parallel on any subset of your instances with: $ knife ssh SEARCH_QUERY interactive This has been a lifesaver for me on several occasions.