How is Docker different from a virtual machine?

Question

I keep rereading the Docker documentation to try to understand the difference between Docker and a full VM. How does it manage to provide a full filesystem, isolated network

Answer 1

This is how Docker introduces itself:

Docker is the company driving the container movement and the only container platform provider to address every application across the hybrid cloud. Today’s businesses are under pressure to digitally transform but are constrained by existing applications and infrastructure while rationalizing an increasingly diverse portfolio of clouds, datacenters and application architectures. Docker enables true independence between applications and infrastructure and developers and IT ops to unlock their potential and creates a model for better collaboration and innovation.

So Docker is container based, meaning you have images and containers which can be run on your current machine. It's not including the operating system like VMs, but like a pack of different working packs like Java, Tomcat, etc.

If you understand containers, you get what Docker is and how it's different from VMs...

So, what's a container?

A container image is a lightweight, stand-alone, executable package of a piece of software that includes everything needed to run it: code, runtime, system tools, system libraries, settings. Available for both Linux and Windows based apps, containerized software will always run the same, regardless of the environment. Containers isolate software from its surroundings, for example differences between development and staging environments and help reduce conflicts between teams running different software on the same infrastructure.

So as you see in the image below, each container has a separate pack and running on a single machine share that machine's operating system... They are secure and easy to ship...