28 December 2022

Containerization vs Virtualization - What Are The Differences?


Both containerization and virtualization are approaches to setting up a software infrastructure for your organization. Are you wondering which one would be a better fit for your organization? Both of these technologies work in different ways and have slightly different functionalities, but the concepts can be confusing, so let's take a closer look at them. 

Virtualization - what is it? 

Virtualization is a method that can simulate real, physical hardware (such as CPU, storage and memory) as a virtual machine. Virtual machines are systems that have been emulated. They can perform all of the functions of a genuine physical computer with its complete operating system. They may also feature a software stack - the combination of hardware and software packages gives us a fully working snapshot of a computing system. 

Virtualization is not possible without the hypervisor. A hypervisor, also called a virtual machine monitor, is the software or firmware layer that enables multiple operating systems to run side-by-side using the same physical server resources. The hypervisor also allows the physical machine to separate its operating system and applications from its hardware to create virtual machines. 

What is containerization? 

Containerization is a form of virtualization - it imitates your machine's operating system. Containers perform functions similar to virtual machines but lack hardware virtualization. The most extensively used container technology is Docker, which uses a public repository. System libraries, external third-party code packages, and other operating system-level programmes are examples of dependencies that a container can include. 

Additionally, an application container allows you to package all the needed apps in a portable environment. You can also run multiple containers at the same time.  

What are the main differences between using virtual machines and containers? 


The first important difference to note is the isolation - while virtualization provides complete isolation from the host operating system and other virtual machines, containerization offers lightweight isolation from the host and other containers but does not guarantee a strong security boundary that a virtual machine would. 


You can deploy individual virtual machines by using the hypervisor software. With the help of Docker, you can deploy individual and multiple containers using an orchestrator like Kubernetes. 

Persistent storage 

For a single virtual machine, you can use a virtual hard disk (VHD) and a server message block (SMB) file share to share the storage by multiple servers. With containerization, you use local disks for local storage for every single node. You can also use SMB for shared storage. 

Virtualized networking 

While containers use an isolated view of a virtual network adapter (therefore offering less virtualization), the VMs use virtual network adapters. 

Virtualization - pros and cons 

What are the advantages of using a virtual machine? 

First of all, virtualization increases your business's IT flexibility and scalability and can also boost your workforce's performance. 

It can reduce possible hardware operating costs, as it does not require actual hardware components to be used. It is usually a cheaper system to implement, as you only need to purchase the license or access from its provider, and you can begin to work immediately, just as you would on a physical computer. The costs are predictable, as you know how much you will pay when you buy the license. 

Virtualization also delivers better uptime. Some providers claim an uptime of 99.99%, and even the budget options offer that. 

There is no need for physical machines or local networks, so as long as you have at least one access point, the virtual environment can be spread throughout the whole company. It can also host more than one complete operating system. 

Interestingly, it can also provide energy savings. Less hardware means less energy is being used to make it work. Thanks to virtual machines and platforms, you do not need to spend money to power many different devices. 

Does virtualization have disadvantages? 

One of the best-known hindrances to effective virtualization is cost. Of course, there are reasonable savings made through a reduction in physical server purchases, but on the other hand, implementing virtualization software can get expensive. To work with virtual machines, you would need to cover the licensing and server costs upfront - this can be especially challenging for startups and small businesses. 

Because virtual machines rely on third-party providers, the security risks are slightly higher than usual. Investing in additional security would be wise if you want your data to be extra safe. 

Unintended server sprawl can also be an issue here - users tend to create new virtual servers because it is easier than reusing the same one again. The service administrator has much more work then, which can slow down the operations. 

Containerization - pros and cons 

What are the benefits of containerization 

First, it is important to note that containerization allows great portability. Since the container includes all dependencies, you can use the app just about anywhere without the need to rebuild it for the new environment. 

It also offers improved security, as applications isolated as containers run in their own self-contained environment, thus preventing any malicious code from affecting other applications.  

Containerization is also one of the most efficient methods of virtualization available. Containers can perform their operations without interfering with other containers, so the host can perform many functions. They do not rely on virtualized computing environments because they use the host's OS kernel. 

What are the cons of containerization? 

Containerization works better with Linux kernel - Windows has a container environment, but it is not supported as much as the Linux environments are.  

If a container is shut down, in most cases all data there is lost. Unless you save a copy of your data somewhere else, you will lose what you worked on. There are ways to save data persistently in Docker, but they are a bit challenging. 

Containers also take up a considerable amount of space - since the applications are packaged there with all dependencies needed. Besides, not every app needs to be containerized anyway: in some cases, it might not provide any benefits. 

Which one is better to use? 

There is no need to compromise between the two as they are two different technologies meant for different situations; both containers and virtual machines can help you reduce costs and increase ROI over time. You may combine the two methods and even run containers on a virtual machine. Containers are preferable for activities with shorter lifecycles, but virtualization can help with longer-term undertakings.  

What is better depends on how you operate, what you want to improve, and what your ultimate goals are - take into account factors like your operations size, team skill set, and workflows. Hopefully, this article brings you some clearance and helps you choose the path you want to follow. 

Roman Charchuła
Software Developer