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CoreOS CEO: We’re not out to replace Docker, just its containers

There was a major shakeup in the world of container-based computing this week when operating system provider CoreOS decided to get into the container space with a new open source project called Rocket. It’s a container runtime environment as well as a set of specifications for how App Containers — what CoreOS calls its container images — are built and function. But the bigger news industry-wide was the suggestion from CoreOS that it built Rocket because developer darling Docker isn’t living up to expectations.

CoreOS Co-founder and CEO Alex Polvi came on the Structure Show podcast this week to clarify that message and to explain the rationale behind Rocket and everything CoreOS does. If you’re interested in the future of containers, distributed systems and even cloud computing, both business-wise and technologically, it’s a must-listen interview. Here are some highlights, but there’s a lot more good stuff.

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We’re fine with Docker, really!

If there’s one point that Polvi really wants to get across, it’s that CoreOS didn’t build Rocket because it doesn’t like Docker — either the technology or the company. He called that notion — expressed by the media, as well as, in numerous fora, Docker founder and CTO Solomon Hykes — “fundamentally flawed.”

The rationale behind Rocket is simple, Polvi explained. Docker is turning into more of a platform, adding in features around cluster management, networking and booting cloud servers, and CoreOS wanted to make sure that the original, simple container component didn’t get lost to the world as that happens. In fact, he says he’s fine with the idea of a Docker platform:

[blockquote person=”” attribution=””]”That’s a fine product, the private cloud is an open territory right now still. So the Docker platform is a product that needs to exist. We just want the simple composable building block to also exist for people that have their own platforms or they’re trying to build their own platform to use as a reusable component.”[/blockquote]

Although, below the surface, it might not be the mutual respect society the companies would like everyone to think it is. Later, while comparing Docker’s move away from containers to VMware’s move away from virtual machines, Polvi noted, “There is a debate as to whether the technology warrants another company like VMware to emerge.”

CoreOS CEO Alex Polvi
CoreOS CEO Alex Polvi

We build what we have to

When you consider the CoreOS business strategy, the reasons for Rocket begin to look a little more clear. Polvi calls the CoreOS lineup of technologies, which also includes a database, registry service, cluster management and other pieces, “a platform for platform builders.” It’s building the “primitives” that people need to build next-generation distributed systems and platforms, as opposed to actually building the platforms (think Heroku or CoreOS partner Deis) where people ultimately deploy applications.

“We are never trying to just take somebody else’s solution and build it,” Polvi said. “We’re trying to fill in the white space and build something that’s technically sound in an area we think is an open problem.”

He contrasts this with Docker, which he says is now becoming more akin to cluster (and container) management plays such as Mesosphere and the Kubernetes project, or VMware. Those technologies might use containers and let users move them around and manage them, but they’re far more about the management aspect than about the containers, or any other pieces of infrastructure, themselves.

Kubernetes works levels above the container, which isn't mentioned on this diagram from Microsoft.
Kubernetes works levels above the container, which isn’t mentioned on this diagram from Microsoft.

In fact, despite the fact that CoreOS has its own cluster-management tool, called Fleet, Polvi said the company actually contributes quite a bit to the Google-led Kubernetes project because it really likes the technology and the trajectory the project is on.

“Docker was a similar thing early on,” he added. “We used it for a year, we collaborated heavily with that community, but then it became clear they were on a trajectory that was no longer what we needed — and what a lot of people needed, not just us.”

Still, Polvi noted, technically, there’s no reason why Docker containers and Rocket can’t coexist provided Docker is willing to work within CoreOS’s container specifications or collaborate with CoreOS to develop a standard container format.

Structure 2010: Sebastian Stadil – CEO, Scalr; William “Skip” Bacon – VP of Products and CTO, Virtual Instruments; Michael A.Jackson – Co-Founder, President, and COO, Adaptive Computing; Jagan Jagannathan – Founder and CTO, Xangati; Alex Polvi – CEO and Co-Founder, Cloudkick; Javier Soltero – CTO for Management Products, SpringSource
A younger Polvi (far left) talking cloud a Structure 2010.

A quick thought on the cloud

We also asked Polvi about the world of cloud computing, where he used to work after Rackspace acquired his last startup, CloudKick, and where many CoreOS workloads will likely run. Maybe old allegiances just die hard, but Polvi thinks Rackspace is actually in a pretty good position as bigger cloud providers such as Amazon Web Services, Google and Microsoft continue to drive down prices.

“Now, because of the competitive pressure of the cloud providers, compute on infrastructure will go asymptotically to free over time, as well,” he said. “If you think about it, what’s left after the hard parts of software are free and the compute itself is relatively free, or free enough? … I think it’s service, that’s how you do it. You help people use all this stuff.”