The Choice Between Virtualization and Containerization

Virtualization and containerization both offer ways for software developers to isolate environments from the physical infrastructure, but they use different approaches to achieve this goal. Choosing between virtualization and containerization depends on knowing the strengths and weaknesses of both, and the most applicable use cases.

What are Virtual Machines and Containers?

Let’s start with the basics of each technology.

Virtual Machines

A virtual machine (VM) provides an environment that acts as a full physical computer system. It does this through hypervisor software, which virtualizes the underlying hardware for use by the VMs. They have their own operating systems, libraries, and kernels you can use for software development and other purposes.

You may only have one physical server, but you can run multiple VMs that emulate a full PC environment. The VMs are isolated from one another and the underlying physical server operating system.

Containers

Containers virtualize the operating system, rather than the underlying hardware. They are isolated environments, but they share the host operating system and other resources, such as libraries. To implement containers, you need containerization technology software.

Container Pros and Cons

Pros

• Portability: Containers share the host operating system and associated resources, so their overall size is small. A container typically has the application and any required dependencies. Moving containers is a simple, resource-light task.
• Optimized resource allocation: You only need a single copy of the operating system for all of your containers, so you use fewer hardware resources compared to a VM. When you’re working with a tight software development budget, being able to pare down the overall resources required for the project can go a long way.
• Easy to update individual software components: If you need to make changes to a specific container, it’s easy to do so. You’re able to redeploy your containers without involving the rest of the application. Patching security holes and adding new functionality is a simple process with this technology.
• Seamless horizontal scaling: Many container orchestration platforms offer scaling for your containers, so you can add the right number of pods for your application. You only scale the containers that require more resources, so it’s a cost-efficient way of handling different software components.

Cons

• Less isolated: Containers share vital resources such as the operating system kernels and libraries, so they have less isolation between the environments. If you’re trying to maximize your security measures, the lack of full isolation may not be ideal for your development requirements.
• You’re limited to one operating system: You’re not able to spin up different operating systems for containerization. The host operating system is the only one available for containers, and any changes to it impacts the full environment.

Virtual Machine Pros and Cons

Pros

• Full isolation for better security: Fully isolated environments stop VMs from impacting one another. A problem with one of the operating systems will not spill over into the other environments.
• Supports multiple operating systems: You can set up as many operating systems as you’d like on your system. You can develop software for multiple operating systems without needing additional hardware, which also makes testing your applications easier.
• Potential for greater overall capacity: VMs typically have more resources than comparable containerization environments, as VMs need everything from the operating system to virtualized hardware for each instance. If you’re not using the maximum capacity of your VM hardware, you can leverage the overage for higher-resource processes.

Cons

• Less portability: The fully isolated VM environment comes at the cost of portability. You may be working with VMs that are packaged into multiple gigabytes, depending on the resources that it has available. You’re not able to quickly move this software to a new destination, and shifting it is a more complicated process than containers.
• Lack of resource optimization: Your VM environments have many of the same resources, duplicated for each instance. This lack of optimization can increase your costs, and you have to predict the overall capacity for all of your environments when configuring the VMs.
• More OS maintenance requirements: The more operating systems you have, the more updates you need to stay on top of. This con is minimal if you have a limited number of environments, but it can quickly add up.

Matching Virtualization and Containerization to the Ideal Use Cases

Get the most out of both technologies by learning more about the use cases at which they excel. They’re valuable tools for every software development team, and using them effectively can help you meet your application goals.

Containers work best for applications that are cloud-native, have multi-cloud deployments, need horizontal scalability, have frequent updates, and have less stringent security requirements.

Virtualization works best when you have high-security requirements, use more than one operating system, have resource-intensive operations, and may or may not be deploying the application to a single cloud.

Using Containers and VMs Together

Containerization and virtualization are not an either/or prospect. You can use both together to great effect. In this configuration, the container’s host operating system is powered by a virtual machine. You’re able to create a dedicated, isolated environment for your containers while sharing the hardware resources with other VM environments.

If you’d like to learn more about choosing containers, VMs, or both, contact us at Datavail. We have the technical insight you need to make the best decision for your business goals.