Most of us are familiar with using virtual machines either in development or in production. They isolate your application (guest machine) from the underlying infrastructure (host machine). Container technologies such as Docker are increasingly being used for cloud deployments, either complementing, or replacing virtual machines.

Containers are a means to create multiple user-space instances over the same kernel. Unlike virtual machines, containers avoid the need to start, and run separate guest operating systems. Typically, each container packages an application and its dependencies in a user-space instance separate from other containers. Unlike virtual machines, they do not have a separate instance of the operating system, making them lighter, and faster to start or stop.

Docker has become the containerization technology of choice with a large ecosystem and wide support among cloud vendors. Docker images are created from a binary image called base image or automatically built from a script called a Dockerfile. This helps you recreate the same environment in production for development or testing purposes, thus ending the infamous excuse but it worked in my machine.