Containers

A container provides a lightweight runtime environment consisting of the core features of VMs and the isolated services of OSes. This makes the packaging and execution of microservices easy and smooth.

As the following diagram shows, a container runs as an application (microservice) within the OS. The OS sits on top of the hardware and each OS could have multiple containers, with one container running the application.

A container makes use of an OS' kernel interfaces, such as cnames and namespaces, which allow multiple containers to share the same kernel while running in complete isolation of one another. This gives the advantage of not having to complete an OS installation for each usage; the result is that the overhead is removed. This also makes optimal use of the hardware: