The Amazon AWS infrastructure is able to create services like Lambda because their engineers no longer provision hardware (ie. new physical servers) when customers create another cloud function or API. Instead, they provision lightweight VM (Virtual Machines). Nobody is lifting a big new metal box onto a rack when you sign up. Software is the new hardware.
Containers aim for the same general architectural idea and advantages that virtualized servers provide —to mass produce virtualized, independent, machines. The main difference is that while a VM provides its own OS (typically called a Hypervisor), a container requires a host OS to provide actual kernel services (such as a filesystem, other devices, and resource management and scheduling) as they do not need to carry around their own OS but operate parasitically on a host OS containers are very...