Docker is transforming the way software is developed, distributed, and run. The advantage is you can encapsulate the entire environment to put it into production with the same characteristics. 

What is Docker?

Docker is one of the best known and most used projects in virtualization issues. Far from being an operating system as such, this open-source platform makes use of the resource isolation functions of the Linux kernel to be able to give rise to independent containers, within which a single application will be executed with its respective dependencies, but always running with a single kernel, that of the real machine, instead of virtualizing one for each container or virtual machine.

What does Docker do?

To understand why Docker is so valuable to software developers, you must first understand how Docker brings (or does not) make changes when developing and deploying software.

In most companies, software development, deployment and delivery is a process with several distinct steps:

• The first step is the design of the application.
• The second is the development of it, writing the code.
• The third step is to mount the code in a test environment and test it.
• The fourth and final step is to package the tested application, deploy it, and deliver it to users.

From a development and deployment point of view, containers can do everything virtual machines do, but better.

The only part of the Docker container software development process that really makes a big difference is the last step.

Containers do not necessarily mean a change in design or code programming (although in some cases migrating legacy software to containers requires some modifications so that the app can run as a set of microservices). Containers also do not fundamentally change the way applications are tested, although they do make it easier to maintain a consistent testing environment. However, the tools for testing are the same.

But when it comes to packaging and deploying an application from development to production, Docker instances make a big difference. They allow developers to put the application inside a container, which is an easily portable software-defined environment.

The differences between Docker and Virtual machines

Although they resemble the classic virtual machines by their nature, we are talking about something more advanced because they offer us greater efficiency and simplicity.

The containers’ portability reduces the problems caused by changing the environment where the application is running to a minimum.

If the virtual machines want to simulate an environment different from ours, the Docker container focuses on creating the application and all the content can be easily ported.

Docker Properties

• Applications are free of dependencies of programs and versions wherever we install them.
• Ability to deploy multiple containers in the same system.
• Compatibility between different systems, including Linux to Windows.
• Ability to share and use public containers from the Docker community.

What is the Docker hub?

It is a repository of docker container images where the different containers that the community has published can be shared with the community.

When is it advisable to use Docker?

• Whenever we want to simplify the deployment of applications.
• Avoid conflicts between programs and systems.
• Improve consistency between development and production environments.

Advantage:

• Version consistency: Since the same images that are tested in development are the ones that end up being deployed in production, it is very difficult for problems related to version control, unexpected codes, etc. to occur.
• Application deployment and update time are significantly reduced.
• Containers can be easily deployed in continuous integration environments.
• It is perfect for a dispersed and clustered environment if you want to get it.

Disadvantages:

• Initially, Docker was developed for use in Linux environments. Clients for Windows and macOS have since emerged, but their nature is still based on LXC (Linux Containers).
• The learning curve can be somewhat complicated and demanding at first, but in the long run, it is a time that ends up being amortized with the savings in rework and set-up times for each deployment in the different environments.

The benefit of using Docker

Docker technology is a benefit for both developers and administrators. On the one hand, developers can focus on developing the application code and forget about its infrastructure. Simultaneously, system administrators can standardize the systems they have to control and reduce their consumption. However, everything is done at the same point in an orderly manner.

This process, and the use of images and containers, allows us to manage our infrastructure in the same way that we managed applications.

Also, Docker allows us to separate the applications from the infrastructure, and thus we can deploy our software in a much faster way. All this reduces the time to put the applications into production.