What Is Containerization? Software Explained

Containerization is a way to package software code and necessary resources into an independent unit that can run on any operating system. Below, you can explore what containerization is, how it began, what benefits you might experience using containerization, and examples of leading industries that use this technique.

What is containerization?

Containerization is a methodology in software development that involves encapsulating an application and its associated elements into a “container.” This container is a self-sufficient unit, allowing the application to run uniformly and reliably across various computing environments. The key advantage of this approach is its ability to isolate the application from any inconsistencies between different systems, virtualizing CPU, memory, and network resources and ensuring that the application performance remains consistent.

Containerization offers a systematic way to achieve application portability, scalability, and resource efficiency. When using this methodology, the technical team can assure stakeholders that the software will function as intended, no matter where they deploy it. The container holds not just the application but also its dependencies, libraries, and binaries, making it easy to simply put these in the container and run the software with little stress.

The origins of containerization

The concept of containerization isn’t as new as you might think. Its roots can be traced back to Unix and the introduction of technologies like “chroot” in the late 1970s. Chroot provided isolated spaces for running processes. However, containerization gained momentum with the introduction of the Docker Engine in 2013. Docker simplified and standardized the process of creating, deploying, and running container applications (known as packaging), paving the way for modern containerization. 

How does containerization work?

The key goal of containerization is to construct autonomous and portable software packages that execute consistently no matter what platform you deploy them. You accomplish this by creating and utilizing container images, which are files that have the data you need to run an application within a container. Container layers are immutable, so you cannot alter them on the host system.

In a containerized architecture, these images are the top layer in a multi-tiered structure. The foundational layer is the infrastructure layer, which refers to the actual hardware responsible for running the containerized application. On top of the infrastructure layer is the operating system. Following is the container engine, which is a specialized software that facilitates the creation and management of containers. This layer acts as the liaison between the operating system and the containers, overseeing resource use and ensuring the containers remain isolated from each other and the underlying infrastructure. Finally, you have the application and dependencies layer, which holds the actual application code along with its associated libraries and configurations. 

This structured approach to containerization systematically isolates and manages applications, ensuring consistency, portability, and efficiency across diverse computing systems.

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Benefits of containerization

Containerization has many advantages, making it a popular software deployment and management option. Key benefits of this methodology are as follows:

• Agile development environment: Containers offer an easier setup compared to virtual machines (VMs). DevOps teams can speed up their development, packaging, and deployment workflows.

• High portability: Once written, containers can run on any system.

• Efficiency: Containers require fewer resources than VMs, which reduces costs, makes scaling easier, and leads to faster boot times. 

• Enhanced security: Containers isolate applications from the host system and from each other. This isolation adds security, minimizing the potential impact of system vulnerabilities.

• Fault isolation: If one container fails, it does not impact the others. This benefits microservices-based applications, where multiple components contribute to the functionality of a larger program. You can fix or scale specific microservices without causing a system-wide downtime.

Drawbacks of containerization

While you may find many benefits of using containers, you may also encounter several drawbacks. Some drawbacks of containerization include:

• Not universal: Though containers are efficient, versatile, and portable, some applications are monolithic—where they don’t necessarily need scalability or fast deployment—and VMs are a better fit.

• Limits with dependencies: Because containers are reliant on and built on a physical operating system, dependencies placed on containers can make them less portable.

• Limited tools: You need tools to monitor and manage containers. However, the industry lacks modern tools.

Who uses containerization? Real-life examples 

Containerization is incredibly popular today, and various companies use it to support microservices and cloud-native applications. To better understand the real-world impact of containerization, you may benefit from exploring some practical examples across various industries and applications. Some well-known companies that use containers include:

• Netflix: Netflix uses containerization to make it easier for the company to scale its services and meet the demands of millions of users. Netflix designed a container management platform known as Titus to power streaming, content systems, and user recommendations.

• Uber: Uber leveraged containerization to manage its growing user base more efficiently. It did this by scaling Apache Hadoop with Docker containers.

• Google: Google was one of the early adopters of container technology. It even developed Kubernetes, an open-source container orchestration platform that has become an industry standard.

• Salesforce: Salesforce uses containers to enable more robust and customizable solutions for its clients. It has a growing list of containers it uses for apps, builder sites, integration, and embedded services.

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Containerization vs. virtualization

Containerization and virtualization are technologies designed to create isolated environments for running applications, but they do so differently. Containers are lighter and faster, sharing the host system’s operating system and resources. This makes them highly portable and quick to start, fitting well in scenarios that require agility, like microservices and DevOps. 

Virtual machines (VMs), in contrast, operate with their own full operating system, making them more resource-intensive and slower to regenerate. VMs create virtualized computing environments, such as the first generation of the cloud. They are the virtualization of physical hardware, whereas containers are the virtualization of an operating system. A VM becomes a “guest” to the host computer, meaning you can edit the guest operating system without compromising the host.

Containerization is often the go-to for flexibility and easy management, while virtualization is optimal when teams want to run multiple operating systems on a single machine. Depending on your needs and priorities, you can choose the right one for you.

Jobs that use containers

As container technology continues to evolve, various roles within the tech industry have emerged that specifically focus on leveraging the power of containers. Take a look at some job titles you may encounter that involve containerization skills:

DevOps engineer

Average annual salary in the US (Glassdoor): $107,294 [1]

Job outlook (projected growth from 2023 to 2033): 17 percent [2]

As a DevOps engineer, you will use your skills in areas such as programming, cloud computing, and software development in order to promote an efficient software development process. DevOps engineering plays an important role in both the development and operations side of software development projects. 

Cloud architect

Average annual salary in the US (Glassdoor): $144,865 [3]

Job outlook (projected growth from 2023 to 2033): 13 percent [4]

Working as a cloud architect means you will help manage your company’s cloud computing system and build cloud applications. Another important component of your job as a cloud architect is developing and maintaining cloud storage systems.

Site reliability engineer

Average annual salary in the US (Glassdoor): $122,814 [5]

Job outlook (projected growth from 2023 to 2033): 17 percent [2]

As a site reliability engineer, you are responsible for maintaining the functionality of websites. To do this effectively, you will need to find opportunities to optimize code and upgrade hardware components, as well as perform general maintenance tasks and troubleshoot problems that arise to keep websites up and running consistently.

Getting started with Coursera

Containerization simplifies applications running by bundling all the necessary components, such as libraries and code, into a package that can run on any operating system. This results in improvements in software applications' agility and fault tolerance.

You can continue exploring containerization with top-rated courses by industry experts on Coursera. Consider completing Amazon’s ​​Containerized Applications on AWS course to discover the fundamentals of containerization in as little as 12 hours.