Advanced Computing in the Age of AI | Saturday, January 28, 2023

Virtual Machines, Containers, & Docker, Oh My! 

Containers have made quite the splash of late, with the rising popularity of Docker, the formation of the Open Container Initiative, and the launch of the Cloud Native Computing Foundation. However, with alternative options like virtual machines dominating the cloud industry, the landscape of what technology should be used when and in partnership with what can become confusing.

Enterprises must fully understand each piece of technology to effectively decide which solution is the best fit for its needs. This means answering questions such as: What does the technology involve? How is the technology used? Who uses the technology?

Virtual Machines:

Virtual machines or VMs have exclusively ruled cloud computing up until recently. VMs are completely virtualized environments. Each VM comes with a full-blown operating system, RAM, storage, and CPU resources. When working inside a virtual machine it acts as a completely self-contained environment located on server hardware in your datacenter.

Upsides: When using virtual machines, a hypervisor layer enables the technology to share resources and run various operating systems – such as Linux and Windows – on the same host, simultaneously on different VMs. VMs also offer better isolation between instances which leads a lot of tech professionals to believe they still have the highest level of security in the cloud computing world.

Downsides: As a virtual machine starts it must go through the entire booting up sequence, which involves loading a full-blown operating system and attributes. This can take several minutes and cause excessive server overhead that leads some VM opponents to qualify them as inefficient and slow. 


Containers have been part of the Linux world for quite some time now. They've evolved so much in recent years because of two key technologies in the Linux kernel: namespaces and control groups (cgroups). Improvements in both of these allow for better isolation of specific processes, which can then be wrapped up in a container to become portable and easier to manage.

Simply put, a container looks like a virtual machine; it has its own space for user processes, services, and its own network interface. In actuality, it’s just a set of user processes running in an isolated space on the host machine. All container instances share the same host kernel of their host node. Containers can be leveraged directly on bare metal or as a second-layer container engine on top of VMs.

Upsides: Bare-metal Linux containers allow each instance to share the same operating system, kernel version, and file system of their host node server while working within separate user spaces. This makes them extremely resource-efficient: They are the lightweight version of VMs.

This means every time a new bare-metal container instance is started, there is no need to fire up a separate full-blown OS, reducing server overhead and sharing server resources much more efficiently. A container may be less than 100 megabytes in size, which means that a single server can host multiple containers, while starting the applications they host almost instantly.

DownsidesThe greatest benefit of containers is also their major shortcoming. Since containers all share the kernel of their host node, you can’t run a different OS in different containers on the same node. If you are running Linux on the host node, that’s what the containers you provision on it need to be running. But you can still run different Linux distributions. Since containers are comparatively new technology, unexpected issues can arise when enterprises leverage them in a multi-tenant environment and operate an entirely container-based infrastructure, leading some experts to think twice before recommending running containers in production.


Recently Docker has become almost synonymous with containers due to its growing popularity, adoption, and coverage. Docker is a type of container engine that allows developers to package an app together with its dependencies into a standard unit and manage containers, images, builds, and more. The technology can be used to containerize existing cloud infrastructure as a secondary layer, be it VMs, Linux- or Windows-based, and isolate applications from each other.

UpsidesDocker containers are open source software, they can run locally on your personal computer, on Linux distributions, and Microsoft operating systems, and are also easily incorporated into most DevOps applications. Simply put, Docker can get more applications running on your hardware, make it easy for developers to create and deploy contained apps, and streamlines management of these apps.

It very elegantly solves the problem of how to get software to run more efficiently and reliably when moving between cloud hosting environments. When using Docker in your development cycle, software runs more smoothly across multiple environments, from the developer’s computer to production.

Downsides: The same issues with containers in general also are valid for Docker containers. Most Docker critics claim it is still not safe enough to run in production and point out that people use it in the early stages of the development process mainly as an application packaging and orchestration tool. Some container proponents have criticized Docker implementations for lacking focus and doing too many things all at once.

There is no cut and dry answer on what types of businesses choose which type of technology. Rather, each enterprise must examine its own specific needs and compare them with the value of each available option. These technologies don't compete in the traditional sense, but can be combined to achieve the specific results an enterprise seeks. In an industry that can appear muddled from the outside, it is essential for decision makers to have a clear understanding of the functions and capabilities of each of these technologies before selecting the best fit for their business.

About the Author:

TTenko1enko Nikolov is the founder and CEO of Kyup and the main driving force behind the company's product development and market growth. With a firm background in the field of web hosting as a managing partner at SiteGround – a leading tech innovator on the web hosting market for more than 10 years now – he has both the vision and the experience to foster the company's business strategy and cater to the high-standards of delivering a truly advanced, next-generation cloud hosting products. Follow Tenko @tnikolov or the company on Twitter @Kyupcloud.




About the author: Alison Diana

Managing editor of Enterprise Technology. I've been covering tech and business for many years, for publications such as InformationWeek, Baseline Magazine, and Florida Today. A native Brit and longtime Yankees fan, I live with my husband, daughter, and two cats on the Space Coast in Florida.

Add a Comment