How Containers and VMs Can Coexist
Nowadays, more and more companies are moving to container-based infrastructure. However, virtual machines (VMs) still hold a significant part of the market. For many organizations, migrations from VMs to containers is a slow and complicated process if it’s feasible at all. Thus, infrastructure management becomes even more challenging, especially for companies running cloud-native services on container-based platforms while keeping legacy applications on VMs at the same time.
How can organizations overcome such complexity? The answer is to have VMs and containers coexist, side-by-side, within the same infrastructure and orchestrated by the same platform. In this way, you can host any and all projects using a single point of management, and perform your transformation to containers gradually, based on current needs and possibilities.
Virtual Machines versus Containers
Before we go any further, let’s cover the main differences between these two virtualization approaches.
Virtual Machines
A VM is a type of virtualization that splits bare metal servers into multiple independent instances with separate operating systems inside. Such virtualization allows you to move away from the approach of running one application or service per physical server, and achieve better capacity utilization. However, the necessity of separate operating systems causes additional overhead in memory and storage footprint that leads to higher resource usage. Also, VMs are notorious for their lack of vertical scaling elasticity and relatively long provisioning time.
Containers
A container is a next-generation virtualization type that significantly simplifies and speeds up creation of isolated containers on the physical server. Each container shares the host OS kernel, as well as its binaries and libraries. As a result, containers are exceptionally lightweight and fast to start. Application and system containers allow for more efficient implementation of microservices principles due to their elasticity and ease of provisioning.
In short, VMs virtualize hardware to run multiple operating system (OS) instances, while containers virtualize operating systems so that multiple workloads can run on a single OS. Hosting on virtual machines is commonly used for traditional, monolithic, “all-in-one” applications. Containers are more commonly adopted by cloud-native applications, as each service component becomes a separate element in a microservices architecture.
Is one better than the other? Well, they are different, but most applications can work either way. Containers can offer multiple benefits such as elasticity and efficiency, ease of delivery and simplicity of management. Still, many customers keep using applications that have not yet been adapted for the new world of containers. In such a case, migrating to a new virtualization model requires a heavy investment in experts, resources and time, which can be economically non-viable compared to just keeping the application as-is.
Running Containers and VMs Side-by-Side
It is absolutely possible to support traditional VMs and containers simultaneously. Thus, you can combine both types of virtualization within the same platform and infrastructure based on your projects’ requirements. This gives you more flexibility for teams to host and manage applications with both cutting-edge technologies in addition to tried-and-true standards and methodologies.
Modernization of legacy monolithic systems is tedious and it is almost impossible to pivot quickly, so it is recommended that you progress gradually with enough time to carefully implement and then analyze the impact of each step. Running VMs and container-based versions of an application on the same infrastructure offers great benefits. For example, when comparing these implementations through tests (performance, resource usage, load handling) or new features analysis (e.g., container scaling), you can check both application types and move forward with the most beneficial option or combine the best results from each approach.
Benefits for Cloud Hosting Providers
If you are a cloud hosting provider, it’s an obvious choice to support both VMs and containers, as you can serve customers from both VM and container market segments. However, it is not exactly that simple. The complexity of orchestration and infrastructure customization scares off most dual-hosting enthusiasts. Usually, hosting providers prefer to stick to one approach. Some cloud providers offer support for both virtualization types, but actually host them on separate infrastructure and use different orchestration platforms.
The flexibility of offering virtualization choice helps cloud hosting businesses differentiate themselves, find new revenue opportunities and engage more potential users. The ability to mix and match containers with traditional VMs can become a deciding factor for many developers and operational teams when choosing a cloud hosting provider for their projects.
At the same time, this combined approach can be a great way to fully utilize available infrastructure, achieving lower TCO and higher ROI, as there is no need to invest in separate physical servers for VMs and containers. In addition, unified management immensely simplifies the processes, requiring less human involvement and time investments.
Give it a try and see how a mixed virtualization approach works for you!