2. Hello Kubernetes

Kubernetes is a cluster manager for Linux containers. While Kubernetes supports other type of containers such as Rocket, and support for more types is to be added, we shall discuss Kubernetes in the context of Docker containers only. Docker is an open source container virtualization platform to build, package, and run distributed applications in containers that are lightweight snapshots of the underlying OS. A Docker image, which is application specific, encapsulates all the required software including dependencies for an application and is used to create Docker containers to run applications in the containers. The Docker containers are isolated from each other and have their own networking and filesystem and provide a Container as a Service (CaaS). Docker is similar to virtual machines based on virtualization platforms such as Oracle VirtualBox and VMWare Player in that it is a virtualization over the underlying OS, but is different in that while a virtual machine makes use of an entire operating system, multiple Docker containers share the kernel and run in isolation on the host OS. Docker containers run on the Docker engine, which runs on the underlying OS kernel.