The Problem Docker Solves

Developers often hear, "it works on my machine". Docker reduces those environment differences by packaging an application with its runtime dependencies.

What is a Hypervisor?

Before containers became common, teams commonly ran applications inside virtual machines. A hypervisor sits between physical hardware and those virtual machines so multiple isolated systems can share the same host.

A cloud example is launching a VM on AWS. You get a full operating system without owning the physical server yourself.

Container vs Virtual Machine

A container shares the host kernel instead of booting a full guest operating system.

What Docker actually gives you

Docker is a platform for building, shipping, and running applications as containers.

docker version
docker run --rm hello-world
docker ps -a