Linux Containers vs Virtual Machines

Among the many distinctions between containers and virtual machines is that one is used for applications and the other is designed for entire operating systems.

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Posted November 20, 2017
By

Matt Hartley


Ever since containers on Linux became popular, determining the difference between Linux containers and virtual machines has become trickier. This article will provide you with the details to understand the differences between Linux containers and virtual machines.

Linux Containers vs Virtual Machines - Applications vs Operating Systems

One of the first things to understand about containers vs virtual machines is that one is used for applications and the other is designed for entire operating systems. This is why you’ll oftentimes see some enterprise applications running in a container instead of its own virtual machine. There are some interesting advantages to using a container over a virtual machine.

One of the biggest advantages to a container is the fact you can set aside less resources per container than you might per virtual machine. Keep in mind, container are essentially for a single application while virtual machines need resources to run an entire operating system.

To make this even simpler, consider the following. If you need to run multiple instances of MySQL, NGINX, or other services, using containers makes a lot of sense. If however you need a full LAMP stack running on its own server, there is a lot to be said for running a virtual machine. A virtual machine gives you greater flexibility to choose your operating system and upgrade it as you see fit. A container by contrast, means that the container running the configured application is isolated in terms of OS upgrades from the host.

Linux Containers vs Virtual Machines - Use Case Scenarios

One of my favorite examples where using a container makes the most sense is with Linux library versions. For example, let’s say you have a mission critical application that requires a specific version of Python. Then you run updates on the box housing the application and suddenly, that Python version changes, rendering said application non-functional.

Another key benefit to using containers is the idea that you can take an application, put it into a container and run it on any OS that supports the container type you’re running. One example of this is when you want to have an application that runs on multiple deployments using different Linux distros. By using a container, you can run a similar application environment on a variety of different distros. Containers provide portability.

One could even make the argument that containers make more sense for speedy cross-distro deployments whereas virtual machines make sense for single application use situations like running a LAMP stack.

Linux Containers vs Virtual Machines - Security

It’s widely accepted that virtual machines offer a bit more in terms of security when compared to containers. This isn’t to say that containers can’t be secured, rather, to suggest that by default virtual machines offer greater isolation overall. Remember, containers share system resources that virtual machines do not.

Some things you can do to minimize risk when running containers include avoiding superuser privileges, making sure the containers are obtained from trusted sources and of course, kept up to date. Thankfully, some containers are digitally signed which helps to determine that you’re getting a container from a trusted source.

Lastly, you need to keep a container to single function duty. Once you start combining software duties under one container, you’ll find you’re better off using a virtual machine instead. To reiterate, containers are for single purpose applications and virtual machines are for multiple purpose applications. Stick to this methodology and you’ll be in a far better situation with both security and overall functionality.

Linux Containers vs Virtual Machines - Selecting the Right Tools

Regardless of the virtual machine or container type, the key to choosing the right one for your needs comes down to researching the abilities of each option. In the container realm, Docker offers a strong enterprise solution. This appeals to companies looking at Docker containers because companies know that they can get the support they need if anything comes up. Docker is also considered to be an enterprise consumer friendly option, especially in Docker Swarms. Comparing Docker Swarms to Kubernetes, it’s widely accepted that Kubernetes is far more complex to set up in advanced environments.

Back on the virtual machine front, I’ve always found that Virtualbox makes for a greater desktop oriented virtual machine environment whereas VMware does a splendid job on the server side of things with their various offerings. VMware has virtual machine solutions ranging from storage to cloud server solutions. There are other options available (various hypervisors, etc), however I think that VirtualBox and VMware represent the two realms of desktop to server virtualization nicely.

Linux Containers vs Virtual Machines - And the Winner Is?

Before trying to decide between a container or a virtual machine, consider the following. You can run containers on VMs should you choose to. Understanding this is important as there are no clear winners or losers here. In fact, the two technologies serve completely different needs.

Containers will continue to see the bulk of the spotlight in the press as they allow their users to run more efficiently with less hardware. On the flip side of things, virtual machines remain a staple in the server and cloud space. Suffice it to say, virtualization isn’t going anywhere and is just as hot as containers.

The one area that I think is worth watching is seeing how things play out between Kubernetes and Docker Swarms. I think it’ll be interesting to see how these two container management technologies playout and which one of these technologies becomes the standard. For awhile, it felt like it would be Docker. These days however, we’re seeing a lot more from the Kubernetes camp. It’s entirely possible that over time we will begin to see Kubernetes grabbing headlines and becoming the top player in the container camp.

What say you? Do you believe that containers are on track to outpace virtual machines? Perhaps instead you believe a combination of the two technologies are where things are headed? Whatever the case may be, hit the comments and let’s hear your view. Are you running a Plex container at home while utilizing the power of a full virtualized environment at work? I’d love to hear about your experiences with these technologies.




Tags: Linux, VM, containers, virtual machines


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