Ubuntu Core 26 enters public preview on AWS, Azure, and Google Cloud

Canonical announced today the public preview of Ubuntu Core 26 images for Amazon Web Services, Microsoft Azure, and Google Cloud.

Ubuntu Core is the immutable variant of Ubuntu. Ubuntu Core pairs the robustness and ecosystem Ubuntu is known for with a modular architecture that lets teams compose tailored systems from strictly-confined packages, known as snaps. Refined over ten years of production deployment on constrained devices, Canonical is now bringing Ubuntu Core to the public cloud, giving enterprise cloud users the exact same drift-free, resilient operational model for cloud appliances and managed services.

Greater consistency, stronger confinement

Public cloud administrators and developers often create public cloud virtual machines from a common image, but then find that they gradually diverge as packages, configuration, and operational changes accumulate. Ubuntu Core offers a different model: define the system as a set of controlled components, confine those components, and deliver updates as complete, auditable revisions. Building a system from more controlled components makes it easier to keep them security-maintained while minimizing unexpected update risk. 

This can be particularly useful for virtual appliances, managed services, and specialized workloads. In cloud appliances, the person designing the appliance is often better placed to take responsibility for keeping the device secure, updated and operational than the person running the cloud instance. In managed services and specialized workloads, operators want to minimize configuration drift and reduce the writable surface of the operating system. 

Here’s a detailed rundown of the key features of Ubuntu Core in the public clouds: 

• Immutable operating-system foundation: reducing unintended changes and configuration drift.
• Transactional updates and recovery: avoiding partially upgraded systems with rollbacks in case of failure. 
• Automatic security updates: the kernel, base system, and applications are updated as independently managed snaps.
• Strict workload isolation: every component of the system is a snap. Snaps are confined through containerization, limiting the system resources available to each component.
• A declarative system definition, captured in a signed model assertion that defines the essential components of the system.
• Cloud-specific kernel snaps: all components of an Ubuntu Core system need to be snaps, while our optimized cloud kernels are traditionally deb packages. We’ve created cloud-specific kernel snaps to deliver the optimized kernel images to these Ubuntu Core images in the public cloud. 
• Cloud guest agents as snaps: traditionally, each cloud has its own guest agent, designed around assumptions such as unrestricted filesystem access, arbitrary process execution, and the ability to modify the operating system. Ubuntu Core deliberately challenges those assumptions. We have packaged the required agents as snaps, making them explicit components of the image with their own update lifecycle and security policy. Under strict confinement, each agent must explicitly declare the system resources and interfaces it needs.

Ubuntu Core is not intended to replace Ubuntu Server for every workload. Ubuntu Server remains the appropriate choice when users need a conventional, general-purpose environment with deb packages, extensive interactive administration and unrestricted host customization. Ubuntu Core offers a deliberately narrower model: build the system from defined components, confine those components and update them transactionally.

Take it for a spin

Ubuntu Core 26 images are available on the marketplaces for AWS, Azure, and GCP. The marketplace images provide the fastest way to launch Ubuntu Core 26 and explore its operating model on each public cloud. They also provide a common reference configuration against which we can test and improve cloud integration.

Learn how to launch a Core image on each cloud:

• Launch a pre-built image on Amazon Web Services EC2
• Launch a pre-built image on Azure
• Launch a pre-built image on Google Cloud Platform

Once you have launched your Ubuntu Core image, try installing a snap:

https://documentation.ubuntu.com/core-on-clouds/how-to-guides/using-ubuntu-core/

The existing list of server snaps can be found on snapcraft.io. You can also learn how to create a snap in our snapcraft documentation.

Give us your feedback

Ubuntu Core has been a stable product for many years, however there are a few areas that are unique to the public cloud that have required specialized work. For this reason, we are launching Ubuntu Core in the public cloud as a public preview, to seek feedback from users testing it out.

You can read more about the public preview and the known limitations of these public preview images in our Ubuntu Core on public clouds documentation. 

Please report defects, missing cloud-agent functionality and other feedback through our public issue tracker:

https://github.com/canonical/ubuntu-core-on-public-cloud

We look forward to learning what you build—and to working with the community on the next stage of Ubuntu Core in the public cloud. Please let us know what you are working on, or have built, in our discourse forum for Ubuntu Core:

https://discourse.ubuntu.com/c/project/ubuntu-core/

Build and control your own images

Once you are familiar with how Ubuntu Core works, you may wish to create your own Ubuntu Core images. Learn more about building a custom Ubuntu Core image for the public clouds in our documentation.

We can also work with companies who want more control over publishing and distributing their appliance images to third parties through a dedicated snap store, such as if an ISV wants to include Canonical’s Expanded Security Maintenance or FIPS components in their virtual appliances.