Containerization has become the latest buzzword in cloud computing, and many believe that it can help modernize legacy systems by creating new, scalable cloud-native applications. So why the need for containerization now?
To understand its need and essence, let’s start with virtualization and the growing use of virtual machines (VMs) in the cloud. Generally, almost all enterprises use the cloud environment (public or private), with instances running VMs with scalability and load-balancing capabilities representing their compute layer.
However, virtualization approaches have had some challenges that made these environments inefficient. These include:
Environment inconsistency – deployment of apps and packages to virtual environments
OS dependency – deployed apps only ran on compatible operating systems
Isolation level – inability to provide instant sandbox above operating system level
Compute consumption granularity – the inability to deploy multiple replicated applications, while load balancing on the app layer only occurred within a single machine and not OS layer
Patching images in production-grade environments – canary and blue-green deployments are not flexible at the cluster level and are challenging to manage across multiple regions
So how can you solve these virtualization issues?
The answer is containerization.
Containerization is more efficient than virtualization, making it a natural evolution of the latter. Whereas virtualization is vital in distributing several operating systems (OSs) on a single server, containerization is more flexible and granular.
It focuses on breaking down operating systems into chunks that you can use more efficiently. Additionally, an application container provides a way to package apps in a portable, software-defined environment.
The market for application container technology that helps enterprises modernize legacy apps and create new, scalable cloud-native software is significant and accelerating.
It’s a form of OS virtualization where you run applications in isolated user spaces called containers that use the same shared operating system. An application container is a fully packaged and portable computing environment:
It has everything an app needs to run, including its binaries, libraries, dependencies and configuration files – all encapsulated and isolated in a container
Containerizing an application abstracts the container away from the host operating system, with limited access to underlying resources – similar to a lightweight virtual machine
You can run the containerized application on various types of infrastructures, such as on bare metal, in the cloud or within VMs, without refactoring it for each environment
With containerization, you have less overhead during startup, and you don’t need to set up separate guest operating systems for each app since they all share one OS kernel. Due to this high efficiency, software developers commonly use containerization of applications for packaging several individual microservices making up modern apps.
Containerization allows software developers to create and deploy apps faster and more securely. Using traditional methods, you develop code in a specific computing environment that often results in errors and bugs when you transfer it to a new location. For instance, when you transfer code from your desktop computer to a VM or from a Windows to Linux operating system.
Containerization eliminates this problem by allowing you to bundle the supplication code together with its related configuration files, dependencies and libraries. You then abstract that single package of software (container) away from the host OS, allowing it to stand alone and become portable – able to run on any platform or cloud, free of issues.
While the concepts of process isolation and containerization are decades old, the emergence of an open-source Docker Engine in 2013 accelerated application container technology adoption. The Docker Engine became an industry standard for the containerization process with a universal packaging approach and simple developer tools.
The industry often refers to containers as lightweight, which means they share the machine’s OS kernel and don’t require any overhead of associating an OS within each application – as in the case of virtualization. Hence, containers have an inherently smaller capacity than a virtual machine and require less startup time, allowing for more containers to run on a single compute capacity as one VM. Consequently, this drives higher server efficiencies while reducing server and licensing costs.
Simply put, containerization allows developers to write applications once and run them everywhere. That level of portability is essential in terms of developing process and vendor compatibility. It also has other benefits, for example, fault isolation, security and ease of management.
Containers encapsulate an application as an executable software package that bundles application code with all its related configuration files, dependencies and libraries that it needs to run. Containerized apps are isolated because they don’t bundle within a copy of the OS. Instead, the developer installs an open-source runtime engine (for example, the Docker runtime engine) on the host’s OS becoming the conduit for containers to share an OS with other application containers on the computing system.
You can also share other application container layers, like common libraries and bins, among multiple containers. It eliminates the overhead of installing and running an OS within each app, making containers smaller in capacity (lightweight) and faster to start up, which drives higher server efficiencies. When you isolate apps and containers, you reduce the chance of malicious code in one container impacting others or invading the host system.
Abstraction from the host OS makes containerized apps portable and allows them to run consistently and uniformly across any platform or cloud. Developers can easily transport containers from one platform to another, like Windows OS to Linux OS. They will also run consistently on traditional “bare metal” servers or virtualized infrastructures, either on-premises or in the cloud. Hence, developers can continue using the processes and tools they want.
You can readily deliver containerized applications to users in a digital workspace. Containerization offers significant benefits to software developers and development teams, ranging from superior agility and portability to better cost controls. Below are the advantages:
Containers are not perfect and have their cons and limitations. First, a surprisingly high amount of setup work is required to develop and launch a container strategy and manage it effectively. There is insufficient app support and dependency, and despite emerging technologies in the area, there is still no complete solution as yet. Additionally, there are not enough qualified, skilled and experienced experts in the area.
While containers increase app flexibility, they add complexity in different ways. These complexities may arise in terms of security, orchestration, monitoring and data storage.
Security: Compared to traditional VMs, containers have a potentially more considerable security risk. They need multi-level security because they have multiple layers. Therefore, you need to secure the containerized application plus the registry, Docker daemon and the host OS.
Orchestration: You can use a single orchestrator for virtual machines, which come with a virtualized solution (such as a VMware orchestrator for VMware). However, you have to select from various orchestration tools like Kubernetes, Mesos or Swarm when it comes to containers.
Data storage for VMs is straightforward, but it becomes complex for containers. For persistent container data, you have to move it out of the application container to the host system or somewhere with a persistent file system. The design of containers is the reason behind its data loss. The data inside can disappear forever once the container shuts down unless you save it elsewhere.
Monitoring: It’s also crucial to monitor containers for performance and security issues. You have the option of using various essential monitoring tools, external monitoring services and analytics to address this challenge. The cloud environment is complicated, so you need in-depth monitoring of security issues.
Still, the advantages of containerization far outweigh the disadvantages. Therefore, deciding whether you need containers will solely depend on your specific cloud requirements.
Due to the benefits of containerizing an application, it’s easy to see why enterprises are rapidly adopting containerization over virtualization. The former is a superior approach to app development, deployment and management. Containerization allows software developers to create and deploy apps faster and securely, whether it’s a traditional monolith (a single-tiered app) or a modular microservice (meaning a collection of loosely coupled services).
You can build new cloud-based apps from the ground up (containerized microservices), and in the process, break up a complex app into a series of manageable and specialized services. You can repackage existing apps into containers that use computing resources efficiently.
Enterprises need to evaluate all their options before deciding to use containerization. They may sound lucrative and impressive at first glance, and they are, but you need to assess whether they are the best option for you. Consider all the downsides against the benefits.
The truth is, digital transformation is inevitable for organizations and enterprises to survive and succeed in our competitive, fast-evolving tech era. Containerization, cloud, big data, blockchain, AI, edge computing and Mobility are some of the trending core tech pillars for digital transformation that enterprises need to leverage.
Additionally, containerization gives small enterprises a new sense of agility. Successful firms operating in the digital economy will run digital-native enterprises and re-architect their operations as per market demands and requirements. Small-sized firms can use containerization to adopt a flexible approach and scale up their services quickly to match larger firms.
The Docker Engine is perhaps the most well-known and used container engine technology worldwide. As the primary piece in a container architecture, a Docker refers to a Linux kernel-based open-source responsible for creating containers in an OS.
When a Docker accesses a single OS kernel, it can manage multiple distributed apps running in their respective containers. The basis for containerization is the software package that developers implement in a single virtual shipment.
Developers create containers from Docker images. Despite their read-only status, the Docker creates a container by adding a read-write file system. It starts a network interface to allow communication between the container and a local host. It then adds an IP address and executes the indicated process. Each container contains the necessary parts required to run a program (files, redundancies and libraries).
Containerization and virtualization technologies enable significant compute efficiencies because they allow developers to run multiple software types (Windows- or Linux-based) in a single environment. However, application container technology has proven to deliver significant benefits over virtualization, making it the favored tech by IT professionals.
Virtualization allows multiple OS and software apps to run simultaneously and while sharing one physical computer’s resources. For instance, you can run both Linux and Windows versions of an OS plus multiple apps on the same server. Developers package each app and its related files, dependencies and libraries (including an OS copy) as a virtual machine. When you run multiple VMs on one physical machine, you can achieve significant savings in the initial capital outlay, operation and energy costs.
On the other hand, containerization uses compute resources efficiently. A container creates an executable software package that bundles app code with the related configuration files, dependencies and libraries it needs to run. However, unlike VMs, containers don’t bundle in an OS copy. Instead, developers install their runtime engines on the host system’s OS, making it a conduit that allows all the containers to share a similar operating system.
As noted earlier, developers often refer to containers as lightweight because they share the host machine’s OS kernel and don’t need the overhead of an operating system within each application. What’s more, you can share other container layers (common libraries and bins) among multiple containers, which means containers have a smaller capacity-requirement than a virtual machine and are faster to start up.
Therefore, multiple containers can run on a similar compute capacity as one virtual machine, which drives up server efficiencies and reduces associated costs like licensing and maintenance.
Containerization is among the latest software development trends, and its adoption will grow significantly in both magnitude and speed. Its proponents believe that it enables developers to create and deploy software and applications faster and securely than other traditional methods. Though expensive, industry players expect the costs associated with containerization to fall as its environments develop and mature.
The use of application container technology is widespread across enterprises and industries. It’s also set for rapid acceleration in the coming years. Most enterprises have already started cloud-native containerization of applications or are decomposing their existing monoliths into containers to gain the benefits that containerization architecture provides.
Now you have gained some insights into containerization, its benefits in enterprise environments, and its advantages and disadvantages. You have also learned about Docker container technology and the difference between containerization and virtualization.
If you rely heavily on virtualization for security and web application segregation, you could likely stand to benefit from containerization.
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