VMs vs Docker vs Kubernetes

Virtual Machines:
A program which simulates as a guest computer with the help of hypervisor(Host).
It makes use of Host CPU, memory, storage and OS and are allocated between the VMs

Docker:
An Open source containerization platform (PaaS) which is used to build, package, ship n run applications in an isolated environment called Containers.
Build the image once, and the run the containers anywhere.
Written in Go-Lang programming Language

Images - Template from which a container can be created from. Its a read only file system which has the snapshot of all the packages, files, libraries and metadata required for the container to run.
Containers - Instance of the image, where the distributed application is running. Its like lightweight VM which runs directly on Host’s OS kernel.
Each container has its own application running in it along with its dependencies and is isolated from other containers.

Kubernetes:
A container Orchestration technology which manages containers and deploys them on multiple hosts . Docker is mainly used as container technology
It automates the deployment, management, scaling, and networking tasks of containers.