Docker is a container management tool. Its the company name which released the Docker Engine tool which helps us to build, run and deploy our applications in laptops, desktops ,vms , cloud anywhere .
Container is the running instance of a docker image.
Once request comes , Docker Client will sent the api request to Docker Server . Docker Server will talk to the containerD which is the industry standard for container run time interface .This will connect to the Kernel which creates isolated PID tree, ROOT FS , Network for the container runtime.
Uses and shares the same linux OS/Kernel and will have multiple PID tree, ROOT FileSystem, Network . These separate PID Tree, ROOT FS, Network creates isolated containers. Each will run as separate isolated process.
Four components - 1. Docker Engine 2. Docker Images 3. Docker Registry 4. Docker Container