RHEL takes up Docker management with Atomic Host

RHEL 7 Atomic Host provides management for both legacy RHEL infrastructure and new container-based applications

atomic nucleus

How do you take a product that's widely and deeply deployed, and rework it to take advantage of a transformative but also disruptive new technology?

That's the issue Red Hat faces in trying to rework RHEL (Red Hat Enterprise Linux) to use Docker, the software-container tech that transforms most everything it touches. But the latest iteration of RHEL hints at how Red Hat can remake RHEL for containers without alienating its existing customer base.

The new product, RHEL 7 Atomic Host Beta, appears to be two products in one. On the one hand, it's fully compatible with the existing RHEL 7 distribution, using the same hardware certifications and ecosystem. On the other hand, Red Hat says it also provides "a stable, optimized container host [for Docker] that isolates the container, including its application and dependencies from the host."

This construction is intended to allow "operations and development teams [to] focus on their core strengths," with the former using the original RHEL infrastructure and the latter using containers. Users can either deploy their own containers or opt for the containerized software available through Red Hat's Software Collections.

Clues to Red Hat's former Project Atomic came by way of its recent release of Fedora 21, which demonstrated how the experimental Fedora distribution could be reworked as a container host. Fedora 21 also included a new package-management and rollback system -- the source of the term "atomic" -- that appears in RHEL 7 Atomic Host.

The Docker side of RHEL 7 Atomic Host isn't deployed as a stripped-down mini-distribution like Fedora 21's Cloud version. Instead, the container host is part and parcel of RHEL. Fedora is being used as a proving ground for Red Hat's server technologies, but not necessarily in a one-to-one alignment. Some of the ideas may only show up in a drastically different form, due to the different demands of Fedora and Red Hat users.

RHEL 7 Atomic Host also can serve as a container orchestration platform by way of Google's Kubernetes project. Red Hat states in its press release that Atomic Host "integrates [Kubernetes] into its container stack providing a layer over the infrastructure ... [enabling] enterprises to build composite applications by orchestrating multiple containers as microservices on a single host instance." That is, it'll be easier for a company with an existing investment in Red Hat's technology to adopt containers since RHEL will be the container host -- and security-conscious admins can more easily reinforce protection on containers by way of SELinux.

Red Hat's approach contrasts with that of CoreOS, which built a new breed of Linux distribution using Docker containers as building blocks. For those concentrating on using containers or starting from scratch, CoreOS seems the better deal, since it incorporates very little other than the essentials. By contrast, RHEL 7 Atomic Host is aimed mainly at those who have already worked extensively with Red Hat.

There might be as-yet-undetermined downsides to Red Hat's forays into containers. InfoWorld's Paul Venezia was concerned that the increased emphasis on server (and container) options for Fedora would make the distribution less useful as the desktop and development environment popular with developers. But Red Hat seems confident Atomic Host will be a boon to IT, no matter how Fedora is reworked in the process of bringing Atomic Host to its core -- and paying -- audience.