Containers and virtual machines (VMs) create self-contained virtualizations, by isolating a physical server’s operating system (OS) from the physical machine and accompanying hardware and allowing it to be used remotely. However, there are key differences between them, which make them suitable for different tasks.
When assessing containers vs VM, we need to have a very clear idea of what we’re talking about. What are the advantages and disadvantages of both? Let’s dive straight in.
Containers – what are they?
Containers are the means by which a host server is separated into isolated segments. They do this by virtualizing the host operating system and running applications on it. When the OS host kernel is virtualized, this usually means that the libraries are shared too.
Benefits of containers
1. Light
Containers are small in size, taking up just megabytes.
2. Portable
Containers are small, so they are easy to port around to where needed. They are platform agnostic, so you can run them pretty much anywhere. You can also orchestrate large numbers with ease.
3. Efficient
Resource utilization is good: resources are shared, so fewer file copies needed.
4. Simple
Very easy to install, not much prior knowledge needed – similar to cloud-based solutions in this regard, such as when a company using SEO SaaS doesn’t need much SEO expertise to prosper. Code is broken down into easy-to-manage chunks, so containers are easy to maintain.
5. Scalable
Scalability can be automatic via container orchestration platforms.
6. Support
Containers have become popular, and with this, there’s been a surge in support available.
Disadvantages of containers
1. Limited
As it uses only one OS, this can limit its usability.
2. Security
Security measures can be a little lightweight. However, there have been some recent improvements, along with a raft of developments in container technology.
Virtual machines – what are they?
Virtual machines are what we call user computers when they are accessing the virtualized OS, together with applications and libraries. A software layer containing a virtual machine monitor (known as the hypervisor) deals with the resource deployment necessary to run more than one virtual machine.
Advantages of virtual machines
1. Versatile
You can virtualize just about any hardware, application, or software. This means you can run whatever OS you like on a VM, so you don’t have to buy different hardware to accommodate a different OS when needed.
2. Secure
Relatively low security risks. One of the reasons for this is that each VM uses a separate operating system, which gives better isolation than would be the case with a shared OS.
3. Resources
VMs can run a large number of operations and are especially good for monolithic applications taking up significant computing power.
4. Scalable
You can add more VMs as and when needed.
5. Support
A good deal of support for VMs is available, just as with containers.
Disadvantages of VMs
1. Size
VMs are big beasts. You’re looking at gigabytes rather than megabytes. This means there might be the odd portability issue.
2. Tied-up
Applications running on a VM are dependent on the OS and emulated hardware environment. Again, portability issues can result.
3. Resource
VMs take up all the resource space allotted to them, even when they don’t actually require it all.
4. Duplication
In copying not just the OS but the libraries and binaries, as well as emulating the appropriate hardware, VMs can take up a lot of storage and computing power.
5. Maintenance
If there’s more than one OS running in each VM, that can mean a lot of updating and maintaining needs to be done.
Containers vs virtual machines
Let’s look at some key areas for a direct comparison of the two.
Portability
Containers score highest here. They can be much more quickly transferred than VMs.
Security
VMs are the most secure. Should the VM be hacked, the virtualization software contains defenses that will hopefully stop any illicit access to the host machine. With containers, it’s easier for a hacker to gain access to the host machine.
OS Flexibility
VMs allow a little more flex in terms of moving between Windows and Linux, for instance. Containers are far more dependent on the precise OS with which they came into being.
Resource usage
Containers come free of resource limits. This means that when one is used, it needs limits applied by the user. VMs use resources based on what is allotted to them by the system.
Graphics
A graphical user interface (GUI) is not usually present with a container, as control of containers is normally performed by command line. With VMs, the choice of GUI and desktop environment is down to the user and what’s available in the host server.
Deployment
Both containers and VMs boast a speedy deployment process. Of the two, containers are a little faster, and you can orchestrate thousands of them with ease.. And with the Java microservice framework, you can fine-tune container deployment to suit.
Conclusion
So, those are the main differences between a container vs VM. Which you choose between will depend on several factors. If security is paramount, VMs have the edge. If portability’s what you need, then containers are the way forward. Or you might want to try a blend of the two. This can deliver the best of both worlds.
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ABOUT THE AUTHOR
Nick Brown – Accelerate Agency
Nick Brown is the founder & CEO of accelerate, a SaaS SEO agency. Nick has launched several successful online businesses, writes for Forbes, published a book and has grown accelerate from a UK based agency to a company that now operates across US, APAC and EMEA.
