Containers vs Virtual Machines (Virtualization) -

18 Jul Containers vs Virtual Machines (Virtualization)

Posted at 07:00h in Virtualization by Simon Spencer

Virtualization tools like virtual machines and containers are brilliant for organizations looking to get more out of their servers and cloud infrastructure. IBM believe that “virtual machine deployment has improved efficiency – and moving to containers can bring even more value.”

Many see VM and container deployment as similar – but there are key differences in the use cases and benefits of each tool.

In general, virtual machines aim to solve an organization’s infrastructure problems as virtualizing cloud infrastructure adds a degree of workload portability. By contrast, containers aim to improve DevOps by solving application issues and facilitating microservices.

What are Virtual Machines? What are Containers? Which is right for your business? In this article, we will introduce answer these questions and give you some key guidance on how to implement each approach.

What are Virtual Machines?

A virtual machine (VM) simply refers to a digital, simulated instance of a computer. This virtualized environment can perform all the same functions of a physical computer – such as running applications – but is isolated from the rest of the system.

Each virtual machine on a physical computer runs its own “guest” OS. This could be a new instance of the same OS – like Windows. But a VM could be running a completely different operating system and software architecture (e.g. ARM vs x86) than the “host” machine.

In a virtual machine, the “guest” OS is fully independent of the “host” – and the VM operates its own kernel. This isolation is a brilliant security asset. For persistent storage – even after the VM has been shut down, Azure offers a virtual hard disk (VHD) for local storage for a single VM.

Virtual machines communicate with the system hardware through hypervisors – which allocate resources, memory, and processors to VMs.

Individual VMs can be deployed using Windows Admin Center or Hyper-V Manager. However, for those deploying multiple VMs at a time, the System Center Virtual Machine Manager is the tool to use.

Advantages of Virtual Machines:

Virtual machines allow users to run multiple “guest” instances on a “host” computer or cloud server. It, therefore, makes it far cheaper to manage multiple system environments – and saves physical space.
VMs allow for a near unlimited number of virtualized environments that act, in practice, as if each instance was its own fully-fledged computer.
Virtual machines provide complete isolation from the host operating systems. This provides a strong security boundary as any suspicious, risky software executed within the VM cannot leak out to the rest of the system or network.
Virtual machines are easy to create, run and delete as you please!

Disadvantages of Virtual Machines:

Given the resource overhead to run and maintain an entire virtualized computer, VMs tend to perform worse than full computers or containers.
If resource requirements are not managed correctly, VMs can become unstable and crash.
VMs can take a lot of storage space. An instance of Windows alone can take up to 5GB of space – with system files, application data and more eating up server storage capacity.

What are Containers?

A container aims for a more lightweight method of virtualization. The key difference here is that a container shares the OS with the host system, along with the host system’s libraries.

Containers are built upon the host OS’s kernel – and contain only the application being virtualized and its dependencies (such as OS APIs). As an entire system does not need to be virtualized, containers can spin up instantaneously.

To facilitate persistent storage, Azure Containers will use Azure Disks for local storage or Azure SMB shares for files shared by multiple containers.

Advantages of Containers:

Containers are far more lightweight than VMs. Whereas VMs take up GBs of space, container node storage space only takes up a few MBs.
Containers are faster to create and run. They can spin up in mere milliseconds.
Without the resource overhead of VMs, containers enjoy significantly higher performance.
Compared to virtual machines, containers boast far higher resource utilization – improving CPU and memory usage.
- For instance, IBM compared how VMs and Containers used a 16-core server with 128GB of memory. 8 dual-core VM environments left 100GB of memory unused, whereas 33 containers shared all system memory between them.

Disadvantages of Containers:

As the host OS, libraries and kernel are shared, there is a lower degree of isolation when compared with VMs. This relatively weak security boundary can result in threats leaking out to the rest of the network.
A container will need to run the same OS as the host.
- Hyper-V isolation can allow earlier versions of the OS to be run, but still cannot enable mix-and-matching of “guest” OS’s.
Given the speed and level of resource utilization of containers – lifecycle management is important to avoid resources and cloud bandwidth being eaten up too quickly. Organizations with cloud resources should remember to scale down their containers – as well as scaling up – to avoid a hefty cloud resource bill.

Which is right for your business?

Virtual machines provide the highest degree of isolation from the rest of your system or cloud infrastructure. If you are turning to virtualization to run risky programs or complete tasks that may jeopardise the security health of your network using a container, a virtual machine is right for you.

There are significant costs to virtual machine management, however. There is a huge resource overhead to consider. Not only do virtual machines take up GBs of storage space, but they also suffer from slower performance.

Containers are a lightweight, more adaptable virtualization method. Without the overhead, containers perform much faster. If you are looking for a high-performing method for, say, hosting microservices, containers are a brilliant option. Containers also boast much greater resource utilization and are therefore more cost-effective. If security is not too much of an issue and full isolation is not required, containers are a safe bet.

If you are looking for the speed of a container and the security of the VM, why not try a hybrid deployment approach?

Get in touch today to implement virtualization effectively

A key takeaway of this debate between virtual machines and containers is the need for smart, careful lifecycle management. We highly recommend working with an MSP like us to deploy and maintain your virtual environments.

Need some help and guidance selecting which virtualization method is right for you? Want some guidance and assistance with deployment? Want to get the most out of your system and cloud resources? Want to know more about a hybrid deployment approach?