Docker vs Rocket: Platforms, Components, and the Future of Containers

Platform vs. Component

CoreOS founder Alex Polvi and Docker founder Solomon Hykes agree that Rocket and Docker are not direct competitors; Rocket competes with libcontainer, the library that defines container configuration options and is crucial to Docker.

Polvi argues that Docker was originally intended as a building block—a simple tool to integrate containers into existing systems—rather than a complete platform. He believes Docker should remain an open component that other systems can incorporate.

He states that Docker has become a platform, which is not inherently bad, but it may no longer be the optimal component for building other systems. Rocket was created to ensure Docker’s original component role persists.

Is Rocket Necessary?

Open‑source projects sometimes produce tools without immediate practical value, yet Rocket aims to address real needs by improving Docker’s security and composability.

Docker replaced LXC, solving usability issues, while CoreOS’s enhancements through Rocket introduce multi‑platform container concepts and promise better security.

Not Everyone Agrees

Hykes acknowledges Rocket offers good ideas but doubts it provides the fundamental improvements—especially in security and composability—that CoreOS claims.

Nevertheless, Rocket’s popularity suggests it meets deep industry demands for a more independent container library that can be easily integrated into projects.

Clearing the Confusion

Enterprises often wonder whether they need Docker, Rocket, or both. The consensus is that both can be valuable: Docker as a platform and Rocket (or similar components) for modular integration.

Polvi emphasizes that open‑source container technologies help companies build components rather than whole products, and that CoreOS’s main competition is not Docker but internal teams that assemble all pieces themselves.

"Docker started as a component for building platforms, a simple tool to help construct things, which is why it succeeded. Today it has become a platform itself, which is not necessarily a bad thing, but it may no longer be the best building block for other systems."

"Docker platform and Rocket are completely different: Docker is a product, Rocket is a component that can be used to build platforms like Cloud Foundry."