​Minimal Ubuntu for containers and clouds

Canonical has a new Ubuntu release just for servers, containers, and clouds.
Written by Steven Vaughan-Nichols, Senior Contributing Editor

By default, Linux comes with a lot of extras. Usually, that's a good thing. But, sometimes you want just the bare necessities of Linux life for your server, containers, and clouds. That's where Canonical's latest Ubuntu release, Minimal Ubuntu, comes in.

When Canonical says "Minimal", they mean minimal. Weighing in at a mere 29MB for the Ubuntu 18.04 Docker image, Minimal Ubuntu could fit on a CD with hundreds of Megabytes to spare.

This is far from the first time Canonical has offered a small-footprint Ubuntu. The minimal Ubuntu ISO image, about 40 MB, is meant for people who download packages from online archives at installation time.

While that release is useful mostly for hobbyists, Minimal Ubuntu 18.04 Long Term Support (LTS) serves as an efficient container operating system. It enables developers to deploy and boot multi-cloud containerized applications faster. The minimal Ubuntu image is already being used as the standard Docker Hub Ubuntu 18.04 LTS image.

Why do this? Because its tiny size enables faster boot ups, better performance, and improved stability for cloud developers and ops.

As Paul Nash, the Google Cloud Group Product Manager, said in a statement, "The small footprint of Minimal Ubuntu, when deployed with fast VM provisioning from GCE, helps deliver drastically improved boot times, making them a great choice for developers looking to build their applications on Google Cloud Platform."

It's not just true on Google Cloud. These advantages work on any cloud. It's available on Amazon EC2, Google Compute Engine (GCE), LXD, and KVM/OpenStack. On Amazon Web Services (AWS) and Google Cloud, this new Ubuntu can take advantage of their hypervisors. Since it's available on Docker Hub, you can also use it in Docker containers on any platform.

There are also downloadable Minimal Ubuntu images, which ship with a KVM-optimised kernel that's tuned for boot speed and size.

Don't think because it's small, it's not powerful. It's fully functional and you can add any Ubuntu programs to it that you'd like. For that matter, if you decide you need two shotguns and a smoking barrel, the "unminimize tool lets you 'rehydrate' your image into a familiar Ubuntu server package set, suitable for command line interaction".

That last part is important because by default Minimal Ubuntu is designed for completely automated operations. Editors, documentation, locales, and other user-oriented features of Ubuntu Server have been removed. What remains are only the vital components of the boot sequence. You can operate it remotely, however, since the Images still contain ssh, apt, and snapd.

But, make no mistake, this is an Ubuntu that's cut to the bone for performance. It will work a treat for containerized applications on the cloud, virtual machines, or servers, but it's no replacement for a full-fledged server.

As, however, we move more of our IT work to DevOps and Kubernetes managed containers, Minimal Ubuntu will find its fair share of users. Indeed, I can see the day when it becomes the single most popular version of enterprise Ubuntu.

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