The typical network transformation journey would look something like this: Linux, VMs, Containers. But this blog is about the road less taken, and how service providers can pass virtualization by using containers and go directly to the cloud.
That’s kind of a revolutionary concept. After all, many in IT have been trained to view virtualization as a necessary evolutionary step. Everything is more efficient in a virtualized environment, we were told. And then containers came along. The new reality is that you don’t need virtual machines to run containers. In fact, there are many cases where virtualization actually hurts the performance of a containerized application. In this article, we discuss the advantages of using containers vs. virtual machines.
Comparing Virtualization vs. Container Management Platforms
How can virtualization be a bad thing? Well, virtualization is great if you need to move and share applications between different physical servers, but it comes at a cost: about 10% of a server’s CPU is dedicated to running the virtual OS. Containers, by contrast, invoke the services they need from their cloud service provider: the storage, load balancing, and auto-scaling services in particular. And that frees up space on the server, which results in much faster performance—in some cases, as much as 25% faster. (source: www.stratoscale.com/blog/data-center/running-containers-on-bare-metal/).
The Benefits of Container Management Platforms
When I talk about containers providing a service, I’m really talking about Kubernetes, the container management platform. Kubernetes not only supports a variety of cloud environments—OpenStack, AWS, Google, Azure, etc.—but understands which environment it’s in and automatically spins up the appropriate service, such as ELB (Elastic Load Balancer) for the AWS environment or Octavia if it’s an OpenStack environment. Kubernetes doesn’t distinguish between multi-tenant servers running virtual machines and bare-metal servers. It sees each VM or server, respectively, as a node in a cluster. So whether or not you virtualize your servers has no impact on your ability to run containers, although it does impact management and performance. Basically, if you’re running a virtualized environment, you have two tiers of orchestration instead of one: the VIM (Virtualization Infrastructure Manager) and Kubernetes.
But wait a minute, you may be thinking, I thought you needed a virtualized environment to run OpenStack? There’s the irony or, more to the point, Ironic. OpenStack Ironic is designed specifically for OpenStack to manage bare-metal servers. With it, you can segregate separate servers into a Kubernetes cluster just as you would group VMs into a cluster. What if you want to run containers on bare-metal servers without OpenStack? This can be done, too and is known as “Kubernetes bare metal”. Load Balancing, in this case, can be provided by the Metal LB project.
If running a cloud environment on bare-metal servers feels like taking a step back to take a step forward, take heart: Chances are, you’ll want both virtualized and non-virtualized servers in your cloud environment. The future isn’t a one-size-fits-all proposition for service providers. There will be cloud services for residential customers that may have ultra-high utilization rates, in which case the performance benefits of a bare-metal server make more sense. For finely sliced enterprise services, however, a flexible multi-tenant model is more desirable. The common thread for both approaches is agility.
Of course, there’s a lot more to this discussion than we could “contain” to a single blog, so feel free to reach out to us if you want to take a deeper dive into cloud architectures.