Types of Virtual Machines: VM Options for Cloud Computing

Access to computing power has come a long way from the early days of data centers. If you needed computing power, you had to purchase physical servers with fixed specifications, wait for delivery, and have technicians install them in racks with proper power and cooling. Scaling up meant weeks of procurement delays and manual hardware installation; scaling down meant leaving expensive servers sitting idle or expending time and effort to decommission.

Now, when users want to spin up a new computing environment, cloud providers like DigitalOcean handle all the infrastructure complexity behind the scenes. You simply select your specifications, click a few buttons, and spin up a functional virtual machine (VM) within minutes.

Virtual machines come in two main types: system VMs that emulate entire computers (what cloud providers typically offer) and process VMs like Java Virtual Machine that run specific applications across different operating systems. In this article, we’ll dig into the types of virtual machines and discuss virtualization, the benefits of virtual machines, and how to reduce your spend on VM resources.

What is a virtual machine?

A virtual machine (VM) is a software-based computer that runs inside another physical computer, creating an isolated environment with its own operating system and applications. For the user, it’s just as if they were using a bare metal machine. There’s no need to separately manage the underlying hardware (such as CPU or memory). With VMs, users can install multiple operating systems (OS) on one system and effectively run applications and processes.

How does virtualization work?

Virtualization creates a software-based computer with dedicated memory, storage, and CPU from the host computer. It uses a hypervisor to host VMs, move resources, and schedule operations to avoid resource overlap or overuse.

There are two types of hypervisors:

• Type 1 (bare metal) runs on a physical machine and has direct access to hardware without an intermediary OS. This type is ideal for server, desktop, and application virtualization.

• Type 2 (hosted) runs on a host machine OS and has the host OS manage resource requests. This option is best for specific use cases on a user’s computing system, such as running Linux on Windows.

Users can—and often will—run both types across their infrastructure and select a hypervisor based on a specific workload type and size. To select the right hypervisor provider, consider hardware compatibility, performance requirements, management tool availability, and cost.

Hypervisors are the foundation for virtualized environments. They can support VMs that emulate hardware, software, networking, and storage components. Examples include:

• Hardware virtualization: Also known as server virtualization, this lets users run multiple OSes on a single server and access CPU and disk space via hypervisor.

• Software virtualization: This allows users to install multiple guest OSes on the same physical device (such as Linux OS on a native Windows OS computer). It also delivers applications from a server to an endpoint device or lets remote users access centrally hosted software.

• Networking virtualization: This type of virtualization lets users create several networks on the same piece of networking hardware. It divides bandwidth between multiple devices, and users can assign traffic to specific sources.

• Storage virtualization: This option consolidates many physical storage devices into a shared storage device. This lets users see how much total storage they have and access it as needed instead of requiring to know how much storage is on every individual server.

Types of VMs

There are two main types of VMs: system and process. The main differences between them are the resources they include and the workflows they support. Even so, they are not mutually exclusive, and users can simultaneously run both in their production environment.

System VMs

System VMs provide a complete version of an OS. They exist as an isolated environment to run applications and allow the user to run multiple OSs on one server or machine. An example is DigitalOcean Droplets.

The benefits of system VMs include:

• Providing a simulated hardware environment that is completely distinct from the host’s instruction set architecture.

• Letting users host multiple OS environments on one primary hard drive with a virtual partition. Also supports file sharing regardless of environment.

• Allowing users to perform tasks without changing operating systems. All created data is stored on the host hard drive.

• Streamlining application provisioning so users can easily create packages, disaster recovery, maintenance, and high availability applications.

The drawbacks of system VMs include:

• Incompatibility between the guest OS and host OS in regards to security protections and software.

• Varying performance between multiple VMs running on the same host.

• Decreasing efficiency once VMs connect to the host hard drive.

Process VMs

Process VMs replicate the VM’s OS as a temporary environment. They are designed to help execute a specific task and delete themselves once the task is completed. An example is using Wine (a compatibility layer that runs Windows applications on Linux) or a Java VM.

The benefits of process VMs include:

• Offering a lightweight, isolated OS that can execute across different platform types. These VMs aren’t limited to a specific system model.

• Exists simply to run a specific process and is destroyed once the process is complete.

• Provides an isolated environment for use cases such as debugging or testing.

The key considerations for process VMs include:

• More ephemeral than system VMs and not as robust feature-wise.

• Require resources that in some cases may be more than simply running the process directly on the machine.

How do containers compare to traditional VMs?

VMs and containers are both virtualization technologies, they function quite differently. So what’s the difference?

Containers package up any components and functions that an application—or a subset of that application—requires to run. Most applications today consist of multiple containers, with each individual container dedicated to a specific service. Containers don’t rely on a hypervisor and are lighter than VMs.

VMs consolidate computing resources and contain an individual OS. This allows users to run much more intensive applications and emulate various computing systems and infrastructure components, such as storage, networking, or software.

Benefits of VMs

The main benefit of VMs is the ability to run multiple computing environments on one machine. But it’s not the only one. VMs also bring positives around infrastructure management, reliability, and security.

• Cost: Because users can run multiple VMs on a single machine or server, organizations can consolidate their physical footprint and save on hardware costs.

• Portability: VMs are self-contained environments that include all necessary compute components, making them easy to migrate across servers, clouds, or data centers via management software.

• Reliability: VMs are isolated from each other and larger system components. This means that if one VM experiences issues (such as a security breach or downtime), other VMs on the same server remain unaffected.

• Scalability: It also makes it much easier for users to increase the amount of available computing power without having to physically provision more infrastructure or buy more servers.

• Security: VMs use their own OS, so they add an extra layer of security between themselves and the host OS. This allows users to run tests or explore security concerns without putting greater infrastructure at risk.

Business use cases for VMs

Along with all the benefits that VMs provide, users can also use the technology to support business outcomes and improve infrastructure. Some business use cases for VMs are:

• Server consolidation: Organizations can reduce sprawl and run numerous physical servers as one or several VMs instead.

• Test and development environments: Users can use VMs as an isolated environment to try new workloads, processes, or security protocols without impacting neighboring systems.

• DevOps support: As sprints come and go, users can spin up, delete, migrate, or adapt VMs to different needs and ensure workflow flexibility.

• Business continuity and disaster recovery: Organizations can replicate systems within cloud infrastructure to easily access backup data and take advantage of VM security features.

• Hybrid computing environments: VMs can not only run on the latest cloud technologies, but they are also suited for on-premises data centers and, in certain cases, may support legacy applications.

Cost considerations for VMs

Though the main costs of VMs might seem straightforward on the surface, multiple factors contribute to the overall deployment’s bottom line. You and your team should consider fixed and variable costs in their calculations.

Fixed costs consist of any hardware required to run the VMs. This includes servers, storage, and software licenses (OS, hypervisor, and management tools). When hosting VMs with a cloud provider, all of these costs are calculated into the pricing and the hardware is included.

Users can then calculate the cost of memory, processing cycles, and storage per month, day, or hour, helping them predict costs over the deployment’s duration.

However, the cost per VM varies depending on the amount of allocated memory, processor cycles, and storage. Certain providers also charge a one-time setup fee for provisioning or configuration. If your team decides to use cloud VMs or go through a service provider, the pricing is more straightforward, and you are simply billed through the cloud provider.

Types of virtual machines FAQ

What is the best type of VM for cloud computing?

The best VM for cloud computing depends on your use case, as different workloads require different hardware configurations. Top considerations during selection should include performance, scalability, security, user experience, and cost.

How do containers compare to traditional VMs?

A traditional VM provides users with an entire OS and emulates computing hardware. A container provides all the components needed for a single application to run instead. This makes it much lighter than a VM and more suitable for running application processes or applications.

What are the benefits of hypervisors in virtualization?

Essential to virtualization, hypervisors provide improved resource use, scalability, streamlined management, isolation, and cost efficiency.

How do VM costs vary across cloud providers (AWS, Azure, Google Cloud)?

Each provider has its own pricing model, and pricing will change based on your desired configuration. Factors that affect costs across providers include region, disk size, memory requirements, network use, data transfer activity, and storage requirements.

References

• Bare Metal Hypervisors: Benefits and Use Cases

• How to Create a Machine

• 12 Benefits of Virtualization in Cloud Computing

Get started with VMs on DigitalOcean

VMs offer many benefits and help organizations scale their infrastructure and quickly access computing resources. However, it’s important to take time to evaluate different VM options before you invest in the technology and start the deployment process. Not all VMs are created equal, and without the right research, you and your team can end up with wasted resources, inefficient performance, and high costs.

Cloud providers offer multiple types of VMs that include different configurations and sizes of processing, memory, and storage resources. Selecting the right VM based on these requirements can ensure peak application performance, effective resource usage, overall infrastructure health, and consistent costs.

DigitalOcean provides a streamlined, robust cloud infrastructure platform that takes the guesswork out of VM provisioning and pricing with DigitalOcean Droplets. And every Droplet is optimized for specific business use cases. We offer:

• Basic: Offer dedicated computing power for applications with sporadic traffic. Ideal for low traffic web servers, blogs, and small databases.

• General Purpose Droplets: Provide an equal ratio of CPU memory and computing power for general computing projects that need committed resources, such as web applications or mixed workloads.

• CPU-Optimized: Support use cases that need sustained CPU performance with low memory requirements. Great for video streaming, gaming, CI/CD, and heavy load front-end web servers.

• Memory-Optimized Droplets: Give 8 GiB RAM for each vCPU and NVMe SSDs to deliver better disk performance for high-transaction workloads.

• Storage-Optimized Droplets: Offer parallelism to deliver faster performance than our regular SSDs and can support data-intensive applications with high throughput.

• GPU Droplets: Provide computing power from NVIDIA H100 GPUs for all AI/ML workloads and data storage.

Use VMs with DigitalOcean.