Kubernetes is at the heart of many existing container management systems — such as CoreOS's Tectonic commercial Kubernetes platform — and recently Microsoft announced it was integrating Kubernetes deep into its public cloud.
Microsoft had already supported Kubernetes on Azure for at least two years, but now things are getting more serious.
"Today, we are taking this support even further and announcing the preview release of Kubernetes on Azure Container Service," Corey Sanders, Azure's director of compute, said in an announcement on the Microsoft Azure site.
"This deeper and native support of Kubernetes will provide you another fully open-source choice for your container orchestration engine on Azure," Sanders continued.
Microsoft also supports Docker Swarm and Mesosphere's DC/OS, but it seems it's Kubernetes that is taking over the world. At the rate things are going, Kubernetes may not be the only horse in the container management system race, but it will be the punter's choice and the bookies' odds-on favorite. So it's worth pondering why this might be.
One person who has looked into container management systems in great depth is Joe Fernandes. He's a senior product manager at the open-source software company Red Hat, and he was part of the team that decided Red Hat should standardize on Kubernetes for Red Hat's open-source OpenShift PaaS offering.
Back in 2013 the company considered building a home-grown container management system, and at the same time it looked at Mesos and talked to Google about its plans for Kubernetes. "What we saw in terms of functionality (with Kubernetes) was far ahead of Mesos and Marathon," he says.
Kubernetes Standing Out in the Crowded Container Orchestration Field
But equally important to Fernandes was Google's heritage in containers, he adds. "They have been on record as saying that everything they run is containerized. Kubernetes is not Borg (Google's resource orchestration software), but it was written from scratch using the experience gained over the space of a decade.
Another important point in its favor (perhaps not surprisingly for an open-source company like Red Hat) was the fact that Google is a committed open-source sponsor. (In fact, the Kubernetes project is now hosted by the Cloud Native Computing Foundation, which Fernandes believes is an added bonus.) "We talked to Google before Kubernetes became an open source project, but now it is faster growing, it is backed by a large number of vendors, and it is rapidly getting new capabilities and running different styles of workloads," says Fernandes.
By contrast, he points out that although Mesos has the backing of Apache, it doesn't have the backing of a large number of vendors. "Only Mesosphere — although a couple of others do offer it as an option in the cloud (like Microsoft)," he says.
The reason behind this, Fernandes believes, is that the codebase of Mesos is not easy to extend or build on. "I don't think they did as good a job of building the open-source community," Fernandes says.
He also believes the biggest competitor to Kubernetes (and one that Red Hat considered, you'll recall) is the do-it-yourself approach. But the reality is that the container world is evolving very rapidly indeed, which makes that approach largely impractical, according to Fernandes.
"Kubernetes is updated four times per year," says Fernandes. "Docker three or four times. Building these solutions yourself is incredibly time consuming, so most enterprises would be better spending their time building apps and getting someone else to build the orchestration platform," he says.
So there you have it. There's no reason to think Mesos or Docker Swarm will be disappearing from the orchestration scene any time soon. But there are good reasons why Kubernetes seems to be proliferating.
There are open core products built on it (like Tectonic) and fully open-source solutions that use it (like OpenShift), and in the future we are likely to see more of both of these types of offerings — all based on Kubernetes.
Paul Rubens is a technology journalist and contributor to ServerWatch, EnterpriseNetworkingPlanet and EnterpriseMobileToday. He has also covered technology for international newspapers and magazines including The Economist and The Financial Times since 1991.