Virtualization and Containers: Better Together

Change is always intimidating. When enterprise virtualization started to rear its head back in the early 2000s, it forced administrators and architects to unshackle their resource planning from single-machine thinking. Now, thanks to virtualization, every machine could be a bunch of machines. Giant servers could host a hundred virtual machines on a single box, driving server consolidation and cost reduction.

When it came time for those same admins and architects to understand and adopt Linux containers, this trend of resource consolidation continued. Along with it came a tremendous simplification of the deployable asset, winnowing it down to a smaller size and removing huge numbers of dependencies and operating system redundancies.

Having moved on from virtual machines and virtualization, it would seem that this technology is destined for the scrap heap in the same way the single-server application has been in the past. But as with most things in enterprise computing, old technology doesn’t just go away, it remains and is often “running the business.”

Working Together

Fabian Deutsch is a senior engineering manager at Red Hat and a maintainer of the KubeVirt project, which began as an attempt to bring virtual machines into Kubernetes. This has been his primary focus since the project kicked off in 2016, and today he’s proud of the progress this Kubernetes subproject has made, now focused entirely on graduating the project at the Cloud Native Computing Foundation (CNCF). Today’s release of Red Hat OpenShift 4.15 includes KubeVirt as the basis of OpenShift Virtualization.

The project’s primary goal has been to provide first-class cloud native support for virtual machines.

“We adopted the mindset and APIs of Kubernetes to tie it into and let VMs benefit from the rich CNCF ecosystem,” said Deutsch. “We doubled down on this ecosystem and the cloud native APIs many other projects have adopted, as well. The greatest strength of KubeVirt is that it ties into the Kubernetes platform almost natively and can therefore be used with many Kubernetes-based projects such as Prometheus, Tekton, CRIO or Argo CD. In the case of Argo CD, we added some glue to make Argo CD work with VMs as it works with containers.”

After three years in the CNCF sandbox and a nearly complete stint in the CNCF incubator, Deutsch is proud that KubeVirt is nearing graduation. While there is still work to be done to reach that goal, end-users should now know that KubeVirt is mature and feature-rich, Deutsch said. Representatives of Goldman Sachs —users of KubeVirt — will talk about their experience in a keynote address at KubeCon EU this week.

It’s All Familiar

KubeVirt is based on KVM, so it’s all the same familiar tooling and virtualization that has been used in wide parts of open-source virtualization throughout the past two decades. The basic concepts, performance and guest-OS compatibility previous users of KVM are familiar with all hold in KubeVirt. The main difference is that users can configure it through their chosen Kubernetes platform, such as OpenShift Virtualization, inheriting features such as RBAC, identity-managed storage and network abstractions, as provided by the platform itself.

This has two results for KubeVirt: first, existing virtualization users familiar with KVM can expect KubeVirt to run their existing VMs just like in the normal standalone virtualization case. Second, due to it’s integration into Kubernetes, CNCF projects like Tekton for pipelines, Argo CD for continuous deployment and Istio for networking are often almost naturally working with VMs, as well.

This brings numerous benefits to users, according to Deutsch.

“Change is hard. And if an operator decides to move to a new platform, the one question to keep in mind is: When I make this heavy investment in moving to a new platform, do I want to keep status quo, or do I want to get myself into a position where I can benefit from a large ecosystem and have a platform that allows me and my end-users to evolve. This mean evolving the way operators work or end-users are deploying applications on the platform. Operators and containers are an opportunity for operators to automate their work and for end-users a means to deliver applications in different and more efficient ways,” he said.

“There are other benefits, too, because it’s more efficient or faster or new associates want to deliver as containers, not VMs, because it’s easier. They have new tools, new IDEs, new software, and the owners of the platform that provides these compute capabilities to their end users can now do so with the self-service that Kubernetes was built around. Having a modern flexible self-service platform is also helping to hire and retain talent. ”

While many traditional virtualization features are available in KubeVirt today, there are still new features arriving in KubeVirt, and with the user base now expanding almost daily, there are new demands for the platform.

“With BootC, we now have bootable containers. We have unified the path for how containers and VMs are delivered. While there’s already so much synergy today, it’s not the end,” he said.

Future plans extend to better documentation. With more workloads migrating to KubeVirt, the need for a wider variety of support increases, and this is the focus for the team now, Deutsch said.

“One big thing we want is to graduate. We need to address some process and governmental things in KubeVirt. We need to give other sides of KubeVirt a little more attention after we added so many features in the past few years,” he said.

“The goal has to be to set it up to be successful over the next five years. We’ve got a lot of attention on the “hard features” — more traditional features that were in conflict with Kubernetes, like hot plugging. We finalized CPU and memory hotplugging, and we are also extending our collaboration with OVN Kubernetes for better networking solutions.”

“We took our time to build KubeVirt,” said Deutsch. “We didn’t want to rush it. We tried to build the best solution on top of Kubernetes and integrate with Kubernetes in the right way. KubeVirt is not a young project anymore, but now is the right time to try it. We have matured.”