Docker Tutorial: Containerization and its Benefits

With the growing number of applications and various software systems that businesses need to use in their everyday tasks to optimize their operations, development teams should care a lot about how these solutions will be built and deployed. 

If they simply introduce multiple stand-alone heavy apps running on-premises, it will be impossible to talk about business efficiency. Managing such solutions will be a real challenge that will lead to continuously growing operational expenses.

One of the ways to address these issues is to rely on containerization principles in custom software development. In this Docker container tutorial, we would like to talk about the capacities of the Docker platform and the benefits of using containers in general.

What is a Software Container?

To begin with, let’s provide a general definition of containerization. This process presupposes putting a software app with its components and dependencies into a remote unit known as a container.

As its glass fellow, a container stores things. Containers are safe, scalable, and easy to use when talking about software development. They are lightweight, easily transferred from one team to another, and can be deployed in multiple environments.

Actually, these characteristics make software containers even more similar to their real-world “relatives”. Right? Given all the opportunities developers can leverage thanks to using software containers in their work, containers are consistently among the critical components of multiple DevOps processes. And the explanation for it is obvious. The nature and peculiarities of containers can simplify buildIng, testing, and deploying DevOps pipelines.

A solid DevOps workflow can also ensure a wide range of benefits for the process of building containerized apps. Among them, the facilitated procedure of making adjustments and introducing improvements, better cost control, more efficient use of resources, and increased collaboration transparency among all stakeholders. 

To work with such a container properly, such as developing and launching applications with it, one will require special software that allows operating-system-level virtualization (containerization in one word). Docker is one of the most popular tools for it. You may have also heard about this software in the context of a well-known Kubernetes platform often applied for running and managing containerized apps.

Advantages of Docker Container

Pushing further the analogy with a glass package or jar in our Docker container tutorial, let’s see what else a Docker container has in its essence:

• It was made to store stuff. A Docker container stores different things and keeps them ready to use anytime as well as its glass fellow.

• It is light. A Docker container weighs only tens of MBs, so you don’t need to wait for an hour until it downloads to a cloud server. 

• Containers are standard. New tendencies in glass container making are unlikely to appear and the same goes for software containers as Docker has determined their shape. Now they are standard and thus quite portable.

• Containers are user-friendly. Glass jars are easy to use as they have the main part and a cover, nothing special. Docker containers have an understandable interface as well that is simple for new users to study out. 

• It works wherever you like. You can take it to any place and make it work everywhere: on your own PC, on your neighbor’s one, or on a cloud service such as Microsoft Azure. Moreover, you can move your container to another Docker environment without difficulties within one OS.

• It is safe. It is safer to run an app in an isolated container. Docker on default allows developers to use its isolating potential on the whole. 

Why Do Businesses Turn to Software Containerization?

Before we proceed to the discussion of the next parts of our Docker tutorial for beginners, we offer you a look at the benefits of opting for containerization for your apps.

• Flexibility and portability. Containerization can ensure a consistent runtime environment. Thanks to this, transferring apps between on-premises and cloud platforms is simplified. This makes the use of apps more flexible and convenient.
• Fast deployment. The deployment process is highly facilitated as an app and all its dependencies can be encapsulated into a single package. As a result, significantly less time is necessary for infrastructure configuration, which is an obligatory step before deploying an application. That’s why we can say that by selecting containerization, development teams can guarantee quicker time-to-market for their software solutions.
• Great scalability. By using containers, developers can ensure quick and straightforward scaling of their solutions up and down following the changing demands. It is possible thanks to the fact that it is relatively easy to manage and replicate containers.
• Efficiency in using resources. As containers are less heavy than traditional apps, fewer system resources are required for running them. More efficient use of resources leads to lower operational costs.

Docker Container as a Program

A Docker container may also appear as a program or, to be exact, as a set of instructions managing parts of application mechanisms. In such a manner, a particular program operates within a container, allowing for sending pieces of pages content you are surfing right now or decoding your commands in order to use them in another Docker. 

The beauty of it is the ability to run several containers at once using a single Docker. No mess up with masses of programs. Anyway, you can make your Docker list containers that you have or even make your Docker remove all containers. Like any other program, it supports all the basic functions and commands.

Docker Image vs Container

Two of the most basic things you come across when using Docker are Image and Container. If a container appears to be more or less clear, an image needs some explanation. In general, a Docker image is a set of layers that serve for code execution in a Docker container. It is a template for running your containers, so you can have a number of them based on a single image.

An image comprises a Docker file, system libraries, dependencies, tools, and settings that are important for running Docker itself. It is based on the OS kernel and most often it is Linux or Windows. Along with a Docker Windows container, for example, you can have a Docker image for any OS as well.

One of the characteristics of Docker images is their immutability. It means that you can’t introduce any changes after you create them. When changes are required, you should create a new container and save the changes as a new image. Even after creating an app, images can be exported into new images. Though building and running Docker containers from an image is possible, images can’t run themselves.

Creating a Docker Container

To use a container, it is good to create it at first. But, then, let’s have another analogy for better understanding. Overall, making a container somehow reminds us of a layer cake, so we will use this idea and see “container baking” from the inside.

Here are the Steps and Main Points of Creating a Container:

• First, you will need a Docker file. It is a text file with a set of commands for performing the creation of a container. Let it be a cake recipe in our case. It contains explanations of layer usage, such as libraries and so on. 

• A recipe and ingredients (your code, for example, or various settings) together compose a Docker image that was mentioned above. In our example, a Docker image is the dough, which can be used to bake a number of cakes (just imagine that your dough is limitless).

• Then comes icing. It is libraries that we implement for work. The main difference from real life here is that you should put icing before baking.
  
• Don’t forget about filling. It is the code you’ve written for your application. It is the main part of an app. Without filling you will get a dry and tasteless cake.

So, the preparation phase is over. Now it is time to bake.

Time to "Bake":

• As you have already installed your oven, you should run it. By the oven we mean a Docker platform that can be downloaded. To do so open your command line and write “docker run”. It’s the same as igniting the oven.

• Your cake will be ready in a few minutes. The delicious baked cake is your Docker container. 

• The final stage is eating your cake. It is the usage of your application. The easiest and most pleasant part of the process.
  
• Still, you can always put the cake in the freezer. Just make your docker stop container in order to use it later.

It takes time and effort to create a container, but as a result, you will get a tool for easier work with applications and a great possibility to develop them in isolation from the system in general. 

Conclusion

We believe that our Docker tutorial for beginners helped you to get a basic understanding of what benefits containerization has and how the Docker platform can help you in the software development process. 

Docker can be great if you create, manage, and run containerized applications. But you do need to stay alone with these tasks.

As Geomotiv, we are always ready to provide any required assistance. You can fully rely on us as our developers have rich expertise in working with software containers and, precisely, with the entire functionality offered by Docker.