Tarides is delighted to announce that MirageOS 4 is finally released! As core contributors to the project, we are proud to have been part of the journey to 4.0.

What is MirageOS? MirageOS is a library operating system that constructs unikernels for fast and secure network applications that work across a variety of cloud computing and mobile platforms. The goal of MirageOS is to give the individual control of their own data and take back control of their privacy.

It achieves these goals in several ways, from securely deploying static website hosting with Let’s Encrypt certificate provisioning and a secure SMTP stack, to ensuring data privacy with decentralised communication infrastructures like Matrix, OpenVPN Servers, and TLS tunnels, as well as using DNS(SEC) Servers for better authentication.

Over the years since its first release in 2013, the Mirage ecosystem has grown to include hundreds of libraries and service millions of daily users, along with several major commercial users that rely on MirageOS to keep their code secure. Examples of this include Docker Desktop’s VPNkit, the Citrix Hypervisor, as well as Robur, Nitrokey, and Tarides itself!

What’s in the New Release? The new release focuses on better integration with existing ecosystems. For example, it is now much easier to integrate with existing OCaml libraries, as MirageOS 4 is now using dune to build unikernels.

There has also been a major change in how MirageOS compiles projects with the introduction of a new tool called opam-monorepo that separates package management from building the resulting source code. The Opam plugin can create a lock file for project dependencies, download and extract dependency sources locally, and even set up a Dune workspace, which then enables dune build to build everything simultaneously.

The new release also adds systematic support for cross-compilation to all supported unikernel targets, meaning that libraries that use C stubs can now have those stubs seamlessly cross-compiled to a desired target.

To find out more about the new release please read the official release post on Mirage.io.

Keep an eye on mirage.io's blog over the next two weeks for more posts on the exciting new things that come with MirageOS 4.0, starting with “Introduction to Build Contexts in MirageOS 4.0” tomorrow!