VMs vs. Containers: Which Is Right for You?

VMs vs. Containers: Which Is Right for You?

September 5, 2023 Off By David

Have you ever encountered a sensation of being inundated amidst the myriad of alternatives for orchestrating your software infrastructure? Chances are, you’re already acquainted with the concepts of virtual machines and containers, yet the discernment of which suits your circumstances optimally can prove formidable. Fret not, for we are suitably equipped to provide comprehensive guidance. As a seasoned IT professional, your pursuit revolves around pliable and scalable solutions tailored for deploying your applications. Within the vast landscape of options, the dichotomy of “VM vs. Containers” takes center stage, underscored by discernible contrasts that require your understanding.

The ensuing discourse will delve into the juxtaposition of VMs and containers, giving you the insight to make an enlightened selection aligned seamlessly with your specific requisites. Our exploration will traverse their operational mechanics, delineating their merits and deficiencies while pinpointing the contexts wherein their efficacy is most pronounced. As we draw towards the outcome of this narrative, you shall have a robust comprehension of both these technological paradigms, thereby encouraging your foray into virtualization with unwavering assurance. The realm of IT infrastructure, notwithstanding its labyrinthine façade, progressively unfolds as more navigable than one might initially assume, especially when approached with sagacity.

When to Use VMs vs. Containers

VMs and containers are two popular virtualization technologies that suit different needs. Here’s how to decide which is right for you.

When to choose VMs

If you need to run multiple operating systems on a single server, virtual machines (VMs) are the way to go. VMs provide full system virtualization, allowing you to run Windows, Linux, BSD, etc. side by side.

VMs are also more secure since each VM is isolated from the host and other VMs. And if one VM is compromised, the others remain secure. VMs are a good option if you need strong security and isolation.

Another reason to choose VMs is if you need to run legacy apps that require an older OS. You can spin up a VM with an outdated operating system to run the legacy app.

When to choose containers

On the other hand, if you want to run multiple instances of the same application efficiently, containers are ideal. Containers virtualize at the operating system level so that you can run many containers on a single VM.

Containers are lightweight so that you can pack more onto a server. They also boot up faster than VMs. So, if scalability and speed are priorities, containers have the advantage.

Containers are best for microservices architectures where you must run many small, discrete applications. They’re also great for development environments since you can quickly spin up and tear down containers.

Both VMs and containers have their place. For some workloads, a hybrid approach using VMs and containers together may provide the most benefits. The right choice for you depends on your specific needs and use cases.

The Pros and Cons of VMs

VMs and containers have pros and cons, so how do you choose which is right for your needs? Let’s break it down.

The Pros of VMs

VMs, or virtual machines, allow you to run multiple virtual operating systems on a single physical machine.

  • Isolation – VMs provide strong isolation between virtual systems. Each VM has its virtual hardware, so if one VM is compromised, it won’t affect the others.
  • Compatibility – VMs can run different operating systems, so you have flexibility in the software and environments you can support.
  • Resource control – You can allocate specific resources like CPU, memory, and storage to each VM.

However, VMs do have some downsides:

  • Resource inefficiency – Running multiple VMs requires a lot of system resources since each VM needs its own OS and software.
  • Boot time – A VM can take several minutes to boot up since it has to load the full OS and software stack.

The Pros of Containers

Containers, conversely, virtualize the operating system instead of the hardware. Multiple containers share the same OS kernel but are isolated from each other.

  • Lightweight – Containers don’t need a full OS to run the application, so they are more resource-efficient. You can run many more containers on a system than VMs.
  • Fast boot – Since the OS is shared, containers can boot in seconds.
  • Scalability – The lightweight nature of containers makes them easy to scale. You can spin containers up and down very quickly.

However, containers also have some downsides:

  • Less isolation – Since containers share the same OS, there is more potential for security vulnerabilities if one container is compromised.
  • OS dependent – Containers are more tightly coupled to the host OS, so you have less flexibility in the environments you can support.

Ultimately, it would help if you weighed the pros and cons of VMs vs. containers based on your particular use case and needs. Both technologies have their place, so a mix of the two works best for your infrastructure.

The Pros and Cons of Containers

Containers offer some attractive benefits over VMs but also have some downsides to consider.

Pros: Lightweight and Portable

Containers are lightweight – they don’t require a full OS to run the application, so they take up less space. This also makes them fast to spin up and down. Containers are also portable – you can build locally, deploy to the cloud, and run anywhere.

Cons: Security Concerns

Because containers share an OS kernel, if there is a vulnerability in the host OS, it could compromise all containers. Containers also typically don’t have the same strong isolation that VMs provide. However, container security is an active development area, and new tools are helping to strengthen container isolation and reduce risks.

Limited Resource Control

With VMs, you can allocate dedicated CPU, memory, storage, and networking resources. Containers share resources, so you have less control and visibility into how much each container is using. This can lead to resource contention issues. However, container orchestration tools are making it easier to set resource limits and quotas for containers to help prevent problems.

Challenges Running Legacy Apps

Not all applications can run in containers. Legacy apps built for a full OS may not work properly in a container and would require modification. Some apps also depend on system-level processes that can’t run in a container. In these cases, a VM is probably a better choice.

Orchestration Required

To harness the power of containers, you need an orchestrator like Kubernetes or Docker Swarm. These help with deployment, scaling, networking, and more. However, orchestrators add additional complexity to deploy and manage. For small-scale container use, an orchestrator may be overkill.

In summary, containers offer many advantages for new, cloud-native applications. But for legacy apps, strict security needs, or limited scale, VMs may still be a better option. The good news is containers and VMs can also be used together so that you can choose the right tool for each job.

Deciding Between VMs or Containers for Your Workloads

How do you decide whether virtual machines (VMs) or containers are right for your workloads? It ultimately comes down to your needs and technical requirements.


If isolation is a top priority, VMs are your best choice. VMs provide stronger isolation since each VM runs its full operating system. This makes them more secure and helps avoid “noisy neighbor” issues where one workload impacts another.

Containers, on the other hand, share an operating system kernel. While containers are isolated, there is still some risk of resources being impacted by other containers on the same host. If complete isolation is critical, VMs are the safer option.

Resource usage

When it comes to resource efficiency, containers have the upper hand. Containers are more lightweight since they share an OS so you can run more workloads on a single server. VMs require a full OS for each workload, consuming more CPU, memory, and storage.

If your priorities are maximizing resource usage and server consolidation, containers are the ideal choice. They can reduce infrastructure costs since you can do more with less.


Both VMs and containers are portable, but containers have a slight edge. Containers are designed to run consistently regardless of the underlying infrastructure. If you install a container runtime, you can move containers between servers with no changes.

VMs are portable but may require additional configuration changes when moving to a new hypervisor or cloud platform. Containers are a bit more “write once, run anywhere.”


Both options work well when orchestrating and managing your workloads at scale, but containers may have a slight advantage. Container orchestration tools like Kubernetes are widely used and support advanced deployment strategies like rolling updates, blue/green deployments, and canary releases.

VM orchestration is also possible, but container orchestration is more turnkey and seamless. If managing hundreds of workloads at scale is a requirement, container orchestration tools are worth considering.

Ultimately, you must evaluate your unique needs and environment to determine if VMs, containers, or a mix of both options is right for you. VMs and containers have their strengths, so combining these technologies may provide the best solution for some workloads.


Which path should you choose – VMs or containers? As with most technology decisions, it depends on your needs and priorities. If security and isolation are top concerns, VMs are your best bet. Need to scale fast and efficiently? Containers will serve you well. The good news is you don’t necessarily have to choose one or the other. Many companies use a mix of VMs and containers to benefit from both. You have to go with what makes sense for your application and environment. The only wrong choice is not evaluating your options at all. Whichever path you go down, keep learning and adapting as these technologies continue to evolve at a rapid pace. The future is bright!