Minimalist machines and the cut-down software stacks that run on them have been the norm at hyperscalers for more than a decade, and now the idea is going mainstream. The operating system is going on a diet, and that is not only to improve performance, but also to make securing the software stack easier and to cut down on maintenance and debugging activities. Presumably the prices for such streamlined operating systems will also come down, reflecting the amount of code that goes into them and, more importantly, making them affordable for large-scale deployments.
As The Next Platform has pointed out before, this is not the first time that streamlined operating systems have come into the market, fit for particular purposes. There was a rash of minimalist Linuxes back in the late 2000s based on various distributions called JEOS, short of Just Enough Operating System, that were designed for custom software appliances that did exactly what the name suggests. The operating system components needed for a particular virtualized software appliance were spun up and nothing more and then distributed with that appliance. It is unclear how popular these JEOS variants were, but SUSE Linux, Canonical, and Red Hat all stopped talking about them many years ago, just about the time that “the cloud” stole all of the oxygen from the datacenter.
Microsoft also had a Server Core variant of Windows Server 2008 which was similarly minimalist variant of Windows, although nothing close to what the company appears to be doing with its upcoming Nano Server edition for Windows Server 10. Nano Server will apparently allow for only the bits that are needed for an application to be loaded onto a virtual machine, Docker container (called a Windows Server Container in the Microsoft lingo), or a new category of container called Hyper-V container, which runs on the Hyper-V server virtualization hypervisor but which can be controlled by the Docker Engine.
With the wave of new application development based on micro-services and containerized software that is just beginning, drawing the lines between the operating system and the container could get difficult. Depending on the workload, the container and the OS will have the smallest footprint as possible, and could quiet likely be woven together in multiple ways to suit needs. This is essentially the approach that CoreOS is taking with Docker and Rkt (pronounced “rocket”) containers, although in this case you cannot install CoreOS Linux without some sort of container. The applications are isolated from the operating system through containers, allowing for the underlying Linux to be updated under the covers and without interfering with the compatibility of the applications. CoreOS has fully fleshed out its container offering with Tectonic, which brings together its Linux, its container infrastructure, and the Kubernetes container management tool into a single suite.
Red Hat has similarly streamlined its Enterprise Linux down to prepare it to be a suitable host for Docker containers with its Atomic Host variant. Lars Herrmann, senior director of product and business strategy at the commercial Linux distributor, tells The Next Platform that the Atomic Host variant of Red Hat Enterprise Linux, which is based on RHEL 7, has fewer than 200 binaries, compared to the 6,500 applications in the full RHEL 7 release. But that is not the important way to look at it. “Atomic Host is really minimized down to what is necessary for an enterprise OS to be a citizen in the datacenter,” explains Herrmann. “It is not as crazy small as you would put on an embedded device, just a kernel and a little app. It is a container host that has interfaces for managing it, stripped down to what is necessary for running containers.” This includes the Linux kernel, Docker containers, various runtimes in the containers, and several tools link this stack back to Red Hat’s systems to keep it all updated.
Over time, Red Hat will containerize all of the key components of its software stack, including RHEL itself as well as JBoss middleware and Gluster and Ceph file systems. Rather than giving Red Hat Atomic Host its own price, it is a deployment option for a RHEL 7 premium subscription for machines with one to two sockets, which costs $1,299. (So much for the thin OS costing less money.)
“Software vendors will find a way to deploy their applications in containers, but there will be a lot of applications that will never migrate. This is a cycle that takes years, sometimes a decade or more.”
At this point, the thin OS movement is being driven by and large by the upwell of industry support behind Docker containers, which has hit a fever pitch this week as Docker raised $95 million in its fourth round of venture funding. That brought its total venture capital haul up to $150 million. Docker says that it will be using the cash to make strategic investments to build out its platform stack – it would be interesting to see Docker make or buy its own minimalist Linux to act as its own Docker host, much as CoreOS and Red Hat have done with their Linuxes and that Microsoft, to a certain extent, is doing with the next generation of Windows. Docker says that it will also be using the funds to do more work with Amazon Web Services, IBM, and Microsoft.
Docker has been downloaded more than 300 million times in its relatively short lifetime, which has to be setting some kind of record on the Internet. The downloads were at 100 million in January, and 3 million this time last year. There are now over 1,200 contributors to the Docker project and the Docker Hub container repository has more than 100,000 different containerized applications in it. Docker estimates that there are somewhere between 3 million and 4 million developers who are using Docker and over 10,000 companies are using Docker Hub. Over 100 companies asked to participate in the Docker Hub Enterprise beta program on the first day, the company says. Docker Hub Enterprise is the first commercial release of the company’s container runtime and management system, and it will be generally available this quarter.
Small wonder then that there is chatter about Docker, which has a mere 120 employees, having a valuation of over $1 billion.
There is such a thing as getting ahead of ourselves. “New applications will drive the adoption of thin operating systems, with born-in-the-cloud applications,” Al Hilwa, program director for software development research at IDC. “Software vendors will find a way to deploy their applications in containers, but there will be a lot of applications that will never migrate. This is a cycle that takes years, sometimes a decade or more.”
One thing that would certainly help drive container adoption is a minimalist price for a minimalist operating system. That would allow customers to dedicate the leftover portion of their OS budget to container management tools and still come out in a better place, financially speaking. The advent of containers will put tremendous pressure on OS pricing, particularly if one vendor comes out with a very low price first. This is precisely what we expect to see happen, and it could come from an oblique angle such as a vendor that does not have an operating system business to protect – like Docker and a few other system management vendors like VMware and Citrix Systems do not – but which want to surf on the container wave.
It will be very difficult for OS vendors to argue that a minimalist OS is worth as much money as a standard distro because it consumes less resources and is more secure, but if they do try that, it sure will be amusing.