The thing with &quot;containers&quot; is that they&#x27;re portable. I want, ideally, to assemble and test my app build in a sort of local micro-copy of the production infrastructure, then push something bit-for-bit identical to that build to the real production infrastructure. Containers easily enable that; source-code-push services leave it an open question.<p>Though, really, if your app uses a lot of fancy IaaS service APIs, even the container-oriented approach still isn&#x27;t a full answer to enabling dev-time local testability with production parity.<p>(Personally, I&#x27;m waiting for a &quot;mock AWS in a box&quot;—a single binary that presents itself as many IaaS service machines on a virtual network interface it creates, without actually doing any of the heavyweight computation required to run e.g. OpenStack&#x27;s DevStack. So the VMs wouldn&#x27;t be VMs but just network-IO-level mocks, etc. I&#x27;d love to plug that some application Docker containers into that.)