Containerization has revolutionized the way we deploy software.

In this post, we will learn about containerization, its benefits, and its common uses. We will also see how it is related to Docker, a popular container platform. By the end, you will have a good understanding of containerization and its role in modern software development.

Want a quick Docker containerization guide? Check out this video.

First, let's quickly go back in time and understand how software was traditionally deployed.

In the past, applications were typically deployed on physical servers or virtual machines. A physical server is an actual piece of hardware - like a big computer - that can be used to run an operating system and various programs. A virtual machine (VM), on the other hand, is a computer, simulated in software. It allows you to run one or multiple operating systems inside another operating system. Essentially, it's a way to create a virtual computer inside your real computer.

Before deploying an application, the necessary infrastructure had to be set up. This included installing the operating system, any dependencies the application needed, and configuring everything to work together. The problem with this is that if you needed to move the application to a different server, you had to go through the whole process again. You had to reinstall everything and make sure every component was configured correctly. This was time-consuming and complicated, especially when you were trying to recreate the exact environment the application was developed for.

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Virtual machines provided a significant improvement over physical servers in this regard. They allowed developers to separate the application from the underlying hardware. You could move your virtual machine to a different physical machine and it would still run the same way. Additionally, it offered developers an easily accessible environment they could use to develop and test in, separate from their main operating system. However, virtual machines still had their own set of challenges.

One of the main problems is that they required a full copy of the operating system and other dependencies. This means they were relatively large and took up a lot of resources. Because of this, it was quite expensive to run multiple virtual machines on the same physical server. Expensive from two perspectives. Not only did it cost a significant amount of money to run hundreds of virtual machines, but it also required a lot of resources such as CPU cores, RAM, and disk space. Moreover, it was difficult to scale applications horizontally (adding more machines to handle more traffic).

In contrast, containerization offers a range of benefits that address these challenges. With containerization, developers can package their applications and their dependencies together in a single container. This container can then be easily shipped and deployed on any platform that supports them. This makes it easier to deploy and run applications in different environments.

What Is Containerization?

Containerization is a technology that allows a developer to package an application and its dependencies into a single container.

To give you an analogy, containerization is kind of like packing all the stuff you need for a road trip into a single suitcase. You can put all your clothes, personal care items, and other essentials into the suitcase. Then you just grab it and go. It doesn't matter where you're going or what kind of car you're taking. As long as you have your suitcase, you have everything you need.

Same thing with containers. You can put all the stuff that your application needs to run - the code, libraries, dependencies, etc. - into this container. Then you ship it off to wherever you want to run it. And as long as the place you're shipping it to has a container runtime (a piece of software) installed, your application will just work. It does not matter what kind of hardware or software is used by the host machine.

This makes it a lot easier to deploy and run applications in different environments. Containerization ensures that the applications run consistently and reliably across different platforms, whether it be a physical server, a virtual machine in the cloud, or running a Windows or Linux operating system.

Benefits of Containerization

Containerization offers a range of benefits to developers and development teams. Some of them include:

• Portability: Containerized applications can be easily moved between different environments. For example, they're easy to move from a developer's laptop to a staging or production environment. No need to worry about the varying configurations between the laptop and the server where the container will be deployed.
• Isolation: Containers provide a layer of isolation between the application and the host system. This is kind of like a protective barrier that helps to prevent conflicts between different applications or dependencies. Each container runs in its own isolated environment. This means it's less likely to be affected by other applications or processes running on the same host machine. Therefore, it is much harder for containerized apps to negatively interfere with one another or the host system. For example, imagine a containerized app has a bug in the code and starts to delete every file it can see. It will only delete files inside that container. That's all that it can access. Files on the host system, and in other containers, will be unaffected as the app cannot reach files outside of its own environment.
• Resource efficiency: Containers allow you to run multiple isolated applications on the same host system. You don’t need to allocate resources to each one individually (as you need to do with virtual machines). This results in a significant reduction of resource utilization and costs. This advantage is particularly beneficial in cloud environments, where charges are often based on resource usage.
• Easy to package, ship, and deploy: As a developer, packing your application into a container image is a straightforward process. You can then upload this image to a container registry, which acts as a centralized server for distributing the image to others. By doing so, anyone can download and run your container image with a simple "docker run" command. This provides an easy and efficient way to deliver your app to users. No need for separate installers for different operating systems, such as Windows, MacOS, or Linux. Instead, a single container image can be used universally, ensuring consistency and ease of use for all users. Your app can be deployed and run in seconds with a straightforward command, making the entire process quick and simple.
• Ease of scaling: Containerization has also made it easier to scale applications as needed. In the past, if you wanted to scale an application, you would often have to manually provision additional servers or other resources. But with containerization, you can use a container orchestration platform (such as Kubernetes) to automate the process of scaling your applications. If you start getting a lot of traffic, the container orchestration platform can automatically spin up more containers to handle the extra load. And if traffic drops off, it can scale down the number of containers you're using. This helps ensure that your applications are always available and performing at their best.
• Enhanced security: By isolating applications in their own containers, you can reduce some security risks. For example, if an app within a container were to be compromised, it would likely be contained within the container and would not have the ability to spread to the host system or other containers, minimizing the potential damage.

Containerization Use Cases

There are many use cases for containerization, including:

Microservices Architecture

Containerization is often used when people are building applications using a microservices architecture. A microservices architecture is a way of designing an application as a bunch of smaller, self-contained services that can be developed, deployed, and managed independently.

Imagine you're building a really big, complex application, like an e-commerce website. With a microservices architecture, you might have one service for the shopping cart, another service for the product catalog, another service for the payment gateway, and so on. Each of these services would be its own self-contained unit that does one specific thing.

Containers make it really easy to package and deploy individual microservices. You can put each service in its own container and then deploy those containers wherever you need them. This makes it easier to scale and manage large, complex applications built using a microservices architecture.

Cloud and DevOps

Containers are often used with cloud services and DevOps practices. Many companies that offer cloud computing services - like Amazon, Google, and Microsoft - have services that make it really easy to deploy and manage containerized applications. This means you can build your application using containers and then just "push" them up to the cloud. The cloud provider will take care of running and scaling your containers for you. This can save you a lot of time and effort. Because you don't have to worry about setting up and maintaining the underlying infrastructure yourself.

In addition, DevOps practices like continuous delivery and continuous deployment are all about getting code changes out to users as quickly and consistently as possible. And containers make this a lot easier. Because they are self-contained and portable, you can just build your application in a container, test it, and then deploy it to production with confidence. The application will run the same way it did in your testing environment. This makes it much easier to deploy code changes quickly and consistently.

Containerization & Docker

Containers have been around for a long time. However, they were complex and really tough to work with. In the past, different tasks required the use of different tools, such as one tool for building containers and another for running them. Plus, you had to be an expert on the underlying infrastructure and container management tools to use containers. This is why most organizations didn't find them to be an attractive solution.

Then Docker came along in 2013 and made it super simple to use containers. It hid all that complexity and made it easier for developers to build, deploy, and run applications using containers. It had everything one could possibly need. With Docker, you could construct images, upload them to a repository, run containers, connect them in a network, and perform a multitude of other container-related tasks. This meant that you only needed to use one tool, instead of multiple utilities, to handle all your container needs. As a result, containers went mainstream and became massively popular.

Today, the use of containers has become widespread across many different industries. They have played a significant role in the adoption of DevOps practices.

Moreover, Docker has become the standard containerization platform. It has grown to become a major player in the world of software development, with a thriving ecosystem and community.

What is Docker?

Docker is a popular containerization platform that allows developers to easily build, deploy, and run applications using containers. Note that Docker is both the name of the company and the name of the technology. However, when most people talk about Docker, they talk about the technology that creates and runs containers.

The Docker Ecosystem

One of the key strengths of Docker is the ecosystem of tools and resources that have been built up around it. There are a wide variety of tools available that can be used to build, deploy, and manage Docker containers. Some of the key tools include:

• Docker Engine: The core component of the Docker platform, responsible for building and running Docker containers.
• Docker Hub: A cloud-based registry (a storage location) for Docker images, allowing developers to share and discover Docker images.
• Docker Compose: A tool for building and running applications that are composed of multiple containers.
• Docker Swarm: A tool for orchestrating Docker containers across a cluster of servers.

In addition to these tools, many third-party tools and resources are available that are built on top of Docker, such as container orchestration platforms, monitoring and logging tools, and more.

Conclusion

So containerization has become a really important part of modern software development. Containers have become a popular way to package and deploy applications. And Docker has emerged as a leading platform for building, deploying, and managing containers.

One key trend that we can expect to see in the future is continued growth and adoption of containerization and Docker. More and more organizations are starting to use these technologies as part of their software development and deployment processes, and that trend is likely to continue.

Another trend is the further integration of containerization and Docker with cloud platforms. Many cloud service providers such as Amazon, Google, and Microsoft already offer services and tools that make it easy to deploy and manage containerized applications. In the future, we can expect to see even more integration between containerization and Docker and cloud platforms. We can also expect the development of new tools and services specifically designed for working with containers in the cloud.

In conclusion, it's clear that containerization and Docker are here to stay. They will continue to play a major role in the world of software development. Whether you're a developer or a DevOps engineer, it's definitely worth learning more about these technologies and how they can benefit your projects.

If you are interested in learning more about Docker, you might want to check out our courses. They're easy to understand and provide a thorough introduction to Docker, giving you the skills and knowledge you need to succeed in the field of DevOps:

• Docker for the Absolute Beginner
• Docker Certified Associate Exam Course