A Practical Introduction to Containers with Docker

What is a Container? A container is an isolated Linux process running on a Linux-based operating system. The keyword here is isolated. A container has its own hostname, root filesystem, process IDs, mount points, and user IDs independent of the host OS. Even though a container is only a Linux process, this isolation of attributes from the host OS makes a container appear as a separate operating system with its own files, users, and network interfaces.