Docker is a free and open-source engine for deploying applications into containers. Docker, Inc. (formerly dotCloud Inc., an early player in the Platform-as-a-Service (PAAS) market) wrote it and released it under the Apache 2.0 license. On top of a virtualized container execution environment, Docker adds an application deployment engine. It’s intended to provide a lightweight and fast environment for running your code, as well as an efficient workflow for moving that code from your laptop to your test environment and then into production. Some of the key feature offered by Docker are:
Easy and lightweight: In just a few minutes, it is possible to Dockerize an application. Because Docker uses a copy-on-write model, making changes to the application is lightning fast: only the parts you want to change are changed. After that, it is possible to create containers that run the applications. The majority of Docker containers launch in less than a second. Because the hypervisor overhead has been removed, containers are now extremely fast, they can be packed into the hosts and make the most efficient use of your resources.
Logical segregation: Developers care about their applications running inside containers with Docker, while Operations is concerned with container management. Docker is intended to improve consistency by ensuring that the environment in which developers write code corresponds to the environments in which your applications are deployed. This reduces the risk of “worked in development, now a problem in operations.”
Fast and efficient development life-cycle: Docker aims to shorten the time it takes for code to be written, tested, deployed, and used. Its goal is to make applications portable, easy to create, and collaborate on.
Encourages Microservice architectures: Service-oriented and microservices architectures are also encouraged by Docker. Each container should run a single application or process, according to Docker. This encourages the use of a distributed application model, in which a single application or service is represented by a collection of interconnected containers. This makes distributing, scaling, debugging, and inspecting applications very easy.
