Containerization allows businesses to virtualize the operating system and install applications in isolated regions called containers.
Containerization is a modern way of creating applications.
Let’s dive into how the legacy system and its architecture hit a roadblock to the point when people started quoting, “My code does not work; I do not know why! Code works, but not sure why!”
As the application grew, the definition of an application changed from just a piece of code to a set of code, binaries, configurations, and a running environment.
Imagine a situation that we have been in frequently in our earlier days. On the laptop, the developer developed some Java 8 code. The same code did not work on a web server/VM. After much troubleshooting, it was found that the server’s Java version was JDK11.
The code stayed the same, but the software that supports the code had a different configuration. Because of something small, developers got into much trouble. The same can be said while transferring a piece of code from Linux to Windows OS.
Legacy system’s management overhead, scalability, and cost-ineffectiveness led to the adoption of cloud computing, wherein workload was hosted on VMs provided by various cloud providers. That is nothing but virtualization.
Virtualization, in simple terms, is several operating systems (OSs) on a single server/VM provided by the cloud provider/data center. Virtualization isolates applications without the need for physical hardware or having to know what is inside.
However, this architecture also did not stand the test of time, and containerization came in.
Containerization focuses on breaking down operating systems into chunks that can be used more efficiently by having their OS. It is a small mini environment running application code without worrying about the operating system or hardware running in the VM.
Now, Let’s discuss containerization in detail.
What is Containerization?
Containerization is a kind of operating system virtualization in which all components of the application, including the environment, a.k.a the operating system it will be running in, are packaged into isolated space on the VM called containers. The underlying operating system for these containers are the same, but they have their own as a part of their configuration.
Containers are not extensive, heavy systems. Instead, they are small, portable, and easy to run or set up. When a developer containerizes an app, the container is separated from the host operating system and has limited access to the system’s resources, like a lightweight virtual machine. The containerized application can run on different infrastructures, like bare metal, the cloud, or VMs, without having to be rewritten.
How Does Containerization Technology Work?
Containerization works by putting all the pieces an application needs into a single virtual unit.
Containerization lets developers bundle the application code with its configuration files, dependencies, and libraries. Separate that single software package (the container) from the host OS. Packaging lets the container stand alone and become portable, so it can run without problems on any platform or cloud. Consider it as a small lego piece from a lego board.
However, containers do not use hardware or kernel resources directly that are virtualized. Containers do not care or worry about the operating system running on VMs.
Instead, containers run “on top” of a platform specifically designed to handle containers and hide the underlying resources. Containers are superior to alternatives such as virtual machines and bare metal servers in speed and size because they only comprise an application’s most important components and dependencies. They also enable the execution of the same application in various contexts without dealing with the associated issues.
Containerization vs. Virtualization
People who are not well versed with the application lifecycle do not always know the difference between containerization, which software like Docker makes, and traditional server virtualization (what hypervisors like HyperV and VMware ESXi enable). However, here is what makes the difference:
In server virtualization, hardware is hidden, and an operating system is run on top of it. Containerization is a way to run an app on top of an operating system. Virtualization depends on the underlying host operating system but does not worry about the hardware unless it has enough resources. Here is a complete list of differences.
|Environment||Containers are packaged with an OS that runs in multiple environments.||Virtualization is built on top of the host, separated by OS appears as a machine.|
|Startup||Containers take very less to little time on startup.||Virtual Machines take a few minutes to startup.|
|Resource||These are a minuscule environment that is not at all resource-heavy.||VMs are resource-heavy with no scaling capability.|
|Implementation||The underlying hardware is virtualized by hypervisors (use of the same hardware).||Containers make the operating system virtual (use of the same OS).|
|Cost||Easier and inexpensive to implement.||These are expensive and heavy bills need to be paid to cloud providers depending on the size of the machine.|
Layers of Containerization
Hardware infrastructure: The foundation of each application is a collection of tangible resources that may be put to productive use. In order for containers to function correctly, these resources must be present. They could be running on a laptop or at one of the many data centers connected to the cloud.
Host operating system: After the hardware layer comes the next layer, the host operating system. As with the hardware layer, this may be as straightforward as installing Windows or *nix on any personal computer, or it could be handled entirely by a cloud service provider.
The Container Engine: This is where things begin to take an exciting turn: the container engine. Container engines are software installed on top of the host operating system and are responsible for virtualizing the resources required by containerized applications.
This layer is the easiest to grasp when Docker is executed on a computer. This layer ensures the container is up and running and manages its overall lifecycle.
Containers: Containerized apps are bits of code that include all of the libraries, binaries, and configuration settings that an app needs to execute. Containers are also known as Docker containers. An application that has been containerized operates as its process in “user space,” which is distinct from the operating system’s kernel.
The Benefits of Containerization
Portability: People complain about an application functioning well in one environment (e.g., staging) but not in another. It is a DevOps dilemma. Usually, the problem is an environmental difference. Perhaps a dependency was updated. The same container images, including dependencies, can be executed everywhere with containerization.
Fast: Containers start faster than virtual machines or bare metal servers. Containers boot in seconds, while virtual machines take minutes, depending on resources and app size.
Resource Efficient: Containers are more efficient than virtual machines since they only include app-specific files. Virtual machines are gigabytes, while containers are megabytes. Containers let teams use server resources efficiently.
Deployment-Development simplicity: Portable containers can be used anywhere. Containerized apps are fast, small, and easy to deploy.
Containerization lets your team build the same image locally and in production. Container apps can reduce situations when something works in one location but not another. CI/CD pipelines support container construction. These benefits improve team productivity.
Troubleshooting: Containerization isolates and separates applications. The failure of one container does not affect the functionality of the others. Development teams can identify and repair a faulty container without affecting others. The container engine can use SELinux access control to find and isolate container issues.
Security: Containerizing programs prevents malware from harming other apps or the host system. Specified security permissions are set to stop undesirable components from entering other containers or limit communications.
Manageability: Automate containerized workloads and services using a container orchestration platform. Container orchestration simplifies administration chores, including releasing new app versions, scaling containerized programs, and monitoring, logging, and debugging.
Continuity: The failure of one container will not affect the others. Developers can fix one container without affecting others. Containerization guarantees operational continuity.
Containerization is a recent software development concept that will become more efficient with time. Its backers believe it helps developers create and deploy software and apps more rapidly and securely.
As containerization ecosystems mature and grow, industry participants expect prices to fall. However, the operation problem is solved, but the maintenance overhead with so many minuscule environments takes a back seat. The next important thing to containerization is orchestration.
Modern apps will not stop here. Kubernetes is the next big thing in containerization and microservices. Kubernetes makes it easier to scale up and manage installations of containers. K8s manages container deployments that are bigger than Docker or LXC. K8s is a well-liked tool for managing containers.
Now that container is a thing of the past, the general recommendation is to jump on to K8s.