Saying that Docker has strayed from its original vision as a modular building block for containers, CoreOS on Monday released a prototype alternative on GitHub called Rocket.
Though it notes that Brandon Philips, co-founder/CTO of CoreOS, serves on the Docker governance board, it disagrees with the direction Docker is taking.
“We thought Docker would become a simple unit that we can all agree on. Unfortunately, a simple re-usable component is not how things are playing out. Docker now is building tools for launching cloud servers, systems for clustering, and a wide range of functions: building images, running images, uploading, downloading, and eventually even overlay networking,…” CoreOS CEO Alex Polvi writes in announcing Rocket.
“We should stop talking about Docker containers, and start talking about the Docker Platform. It is not becoming the simple composable building block we had envisioned.”
It’s asking for input on a command line tool for running what it calls “App Containers,” especially the security features it has added to the meta-data service.
The post calls the Docker process model – sending everything through a central daemon – “fundamentally flawed,” making forking the project untenable.
“To ‘fix’ Docker would essentially mean a rewrite of the project, while inheriting all the baggage of the existing implementation,” Polvi writes, adding, “We cannot in good faith continue to support Docker’s broken security model without addressing these issues. Additionally, in the past few weeks Docker has demonstrated that it is on a path to include many facilities beyond basic container management, turning it into a complex platform. Our primary users have existing platforms that they want to integrate containers with. We need to fill the gap for companies that just want a way to securely and portably run a container.”
CoreOS, which InfoWorld recently called the preferred distro for Docker, plans to continue to support it. At the same time, Rocket won’t be limited to CoreOS, but can run any flavor of Linux.
Meanwhile, in a blog post Monday, Docker CEO Ben Golub asserted that that “only a small number of vendors” disagree with Docker’s overall direction and questioned the motives and timing of the CoreOS announcement.
“As Docker is open source, and Apache-based, people are free to use, modify, or adapt Docker for their own purposes. They are free to use Docker as a single container format. They are free to build higher level services that plug into Docker. And, of course, they are free to promote the notion of an alternative standard, as the folks behind Rocket have chosen to do,” he wrote.
“While we disagree with some of the arguments and questionable rhetoric and timing of the Rocket announcement, we hope that we can all continue to be guided by what is best for users and developers.”