What is docker and its usage

"Docker is an open platform for developers and sysadmins to build, ship and run distributed applications."

 

this is a very brief definition.

 

In shortest words, using Docker you can create mini virtual machines inside a virtual machine on Azure.

 

I suggest you read following articles on C# Corner:

 

http://www.c-sharpcorner.com/UploadFile/mahesh/understanding-basics-of-docker-containers/

http://www.c-sharpcorner.com/article/introduction-to-docker/

http://www.c-sharpcorner.com/article/getting-started-with-docker-and-Asp-Net-core/

http://www.c-sharpcorner.com/article/docker-on-windows/

 

I also suggest to check articles on MSDN too

 

 

please mark my answer as accepted if it fulfils your questions.