Liri Blog

Updates for January, 2020


Photo by Glen Carrie on Unsplash

January was all about making progress on how Liri OS live images.

Previously, the images were made with traditional packages with kickstart files.

I wrote a Python module for the Calamares installer, that deploys the OS tree into the root partition. However this is excruciatingly slow because at the moment we don’t have a fast Web site, in order to reduce costs (all the expenses are out of my wallet).

If the image is made with OSTree itself, the same repository on the image can be used to deploy the operating system on the root partition, without involving the network at all.

At the time of my research for already existing tools, nothing was found. Then Fedora CoreOS started doing something like that, but it’s too complex and focused on their needs.

So I came up with oic, also known as ostree-image-creator.

It’s a simple tool written with Rust, that creates live images. You can use it with ostree, it doesn’t need rpm-ostree.

In the future it will be extended to disk images as well.

Our OSTree repository now has a live branch, derived from the actual branch that will be installed on users’ computers. The live branch installs Calamares and dracut modules specific to its bootstrap, plus a setup service that creates the liveuser user.

The difference with the previous images is that only /etc and /var are writable, and they are not persistent.

Another important Rust program was made: ostree-upload.

We build the OSTree repository in a separate CI machine and want to upload the objects to the public OSTree repository.

This program receives the objects from the CI machine and store them in a temporary directory, until the process is done. Once all objects are transfered, the new changes are published.

This is better than using rsync, there’s no risk that users will fetch from the OSTree repository during a synchronization.