What is Docker?

Docker is an open source project designed to help with application deployment using software containers. This quote is from the official Docker page:

"Docker containers wrap a piece of software in a complete filesystem that contains everything needed to run: code, runtime, system tools, system libraries - anything that can be installed on a server. This guarantees that the software will always run the same, regardless of its environment."

Docker, therefore, in a similar way as virtualization, allows packaging an application into an image that can be run everywhere.

Containerization versus virtualization

Without Docker, isolation and other benefits can be achieved with the use of hardware virtualization, often called virtual machines. The most popular solutions are VirtualBox, VMware, and Parallels. A virtual machine emulates a computer architecture and provides the functionality of a physical computer. We can achieve complete isolation of applications if each of them is delivered...