By now I'd hope everyone has heard if not used docker by now if not

Do it now !

Docker is a tool that allows to to spin up things called containers which people in the know will be quick to inform people
Containers ≠ VMs
Docker blog on the subject
The TLDR of the blog is:

docker runs on a shared base of a docker host and also they are built usually for one or a few purposes not an entire machine with GUI.

But they are usually command line only (with exception)
So why use docker:

  • Good for repeatable environments
  • Can mange several containers at once using swarm
  • In swarm mode can load balance without action

The great thing about docker is that it lowers the attack surface that an attacker can hit as the ports can be exposed on a per container basis. And containers can have hard limits imposed to prevent Denial of service or resource starvation attacks.

The best way to experience docker is to set it up and play with it as each container can be redeployed if you break something. So go wild