In 1956, an American trucking businessman named Malcom McLean created the first metal shipping container. This was an amazing idea because it revolutionized International trade. But even Malcom wouldn’t have thought that the concept will be used in modern day operating systems. Oh, Malcom woudn’t have thought there would be Docker tutorial as well!

Consider the ship as an application/system, the containers as software packages/database servers, etc. The containers are individual units. But they are nearby for easy communication and uniform load management. This is just an idea so you could visualize it in a better way. Have you heard about Docker? It is a tool that helps in packing, shipping, and running applications. All this within the container itself. Even IT giants like Google, VMware, and Amazon are building services that support Docker. So it is important to clear the basic concepts and this Docker tutorial is exactly meant for it.

So let us begin the Docker tutorial. Are you ready?

What do “containers” and “VMs” mean in terms of Docker?

We will individually discuss containers and VM’s but first of all, why do they exist? Both of them have similar goals. They isolate an application and all its dependencies. The isolation converts them into a self-contained unit that could run anywhere. Further, the containers and VM’s don’t need physical hardware. So the cost and maintenance reduce significantly. The computing resources are used efficiently and there is a reduction in energy consumption.

Now you must be thinking that what is the difference between containers and VM’s? Their objectives are similar as well! The main difference is in their architectural approach. So let us discuss them individually and understand this difference.

Virtual Machines

VM or Virtual Machine is simply a virtual computer. It executes each and every program like a real computer. It runs on top of a physical machine with the help of a hypervisor. As such we are discussing a virtual machine, but hypervisor is related to the physical machine. The hypervisor runs on some host machine or on bare-metal (a computer system environment, usually a hard-disk used for operating an OS).