What is Docker?
Docker is both, a brand and a technology. It was developed under the Open Container Initiative by Docker (the company, formerly known as dotCloud) when it virtually went bankrupt. Docker (the product) not only helped it raise funds, but also paved a way for its strong revival into the game. On a Linux platform, it allows an end user to run multiple containers out of which each container can hold a single application. In precise technical terms, when you run an application on an operating system, it runs on its "user space," and every OS comes with a single instance of this user space. In Docker, every container has one separate user space to offer. What this means is that containers enable us to have multiple instances of user spaces on a single operating system. Therefore, in the simplest terms, a container is just an isolated version of a user space. That’s it!
How Is It Different From VMs?
Docker is different from a VM in the following ways: