Sebastian Wiesner

Scala software developer. System engineer satellite mission planning. Rust. Arch.

We have a few Java libraries and SOAP clients around, based on jaxb, jaxws, and other such relicts. Sometimes we don’t touch these for years, and yet they still run on contemporary JDKs with only moderate difficulties.

We have a .NET/Winforms based desktop application from about 15 years ago, which still runs on contemporary .NET 4 with only marginal changes.

In our Angular app which is but three years old we already went through two major deprecations and migrations which took us two months each, and where we had to touch every single part of the code base.

The older I get the more I learn to appreciate Java.

#gnome #typescript Discuss...

The ecosystem for GNOME Shell has come a long way in the last few years. We now have a comprehensive guide for extension developers and good API docs for the underlying native libraries. The API documentation in GNOME Shell itself is still lacking, but meanwhile its Javascript source code is a surprisingly good and readable reference.

With GNOME 45 the shell took another big step: It finally uses ES modules now instead of the legacy import syntax of GJS. While this causes major breakage for all extensions, requiring every single extension to be ported to the ES modules, it finally enables mostly seamless integration with standard Javascript tooling which is increasingly build around ES modules these days.

Together with another recent tool this means we finally have Typescript for shell extensions!


#systemd #rust

Systemd has this feature which lets you change the log level of a service on the fly. You can actually do this:

$ sudo systemctl service-log-level systemd-resolved.service debug
$ resolvectl query
$ sudo systemctl service-log-level systemd-resolved.service info

to get a debug log of systemd-resolved trying to resolve a specific domain.

This is backed by dbus: If a service listens on dbus and has its bus name defined in its unit file then it can expose the log control interface on its bus connection to let systemctl change its log level and log target.

All of systemd's own services support this interface, but unfortunately it hasn't seen wide-spread adoption outside systemd yet. Which is kinda sad, because it's really a great feature for debugging.

I certainly plan to use it more, so I put up on


#archlinux #systemd #secureboot #dracut #sbctl


Update: I no longer use dracut, and the corresponding part of this blog post no longer reflects my setup.

This article describes my Arch Linux setup which combines Secure Boot with custom keys, TPM2-based full disk encryption and systemd-homed into a fully encrypted and authenticated, yet convenient Linux system.

This setup draws inspiration from Authenticated Boot and Disk Encryption on Linux and Unlocking LUKS2 volumes with TPM2, FIDO2, PKCS#11 Security Hardware on systemd 248 by Lennart Poettering, and combines my previous posts on these topics.


#dracut #luks #sbctl #archlinux #systemd #secureboot


Historically cryptsetup and LUKS only supported good old passwords; however recent systemd versions extend cryptsetup with additional key types such as FIDO tokens and TPM devices.

I like the idea of encrypting the rootfs with a TPM2 key; it allows booting without ugly LUKS password prompts but still it keeps data encrypted at rest, and when combined with secure boot also still protects the running system against unauthorized access.

Secure boot will prevent others from placing custom kernels on the unencrypted EFI system partition and booting these, or changing the kernel cmdline, in order to obtain root access to the unlocked rootfs. LUKS encryption with a TPM-based key bound to secure boot state protects the data if someone removes the hard disk and attempts to access it offline, or tries to disable secure boot in order to boot a custom kernel.

I’ve covered secure boot setup in a past article; this article talks about the TPM2-based encryption.


I just learned a nice trick: On Linux I can actually define custom sequences for the Compose key.


#kubernetes #gitlab #docker


A node hosts a Gitlab runner and a small k3s cluster which runs a few services as regular kubernetes deployments. A CI job pinned to that runner builds Docker images for these services services, updates the image of the corresponding deployments, and starts a few system and acceptance tests. The CI job does not push those images to the in-house registry; to avoid polluting the registry with hundreds of images it just builds locally.

Each test then scales each deployment to zero replicas to effectively stop all services, clears the system’s underlying database, and scales the service deployments back to a small number of replicas sufficient for testing.

The whole thing runs fine until one day the replicas randomly fail to start.



Some electron-based flatpaks (e.g. Mattermost, see for some reason ignore Gnome’s HTTP proxy settings. In this case we can set the proxy directly inside the affected flatpak.


#archlinux #systemd

LWN recently covered a comprehensive guide about discoverable GPT disk images by Lennart Poettering.


#archlinux #secureboot #dracut #sbctl


I started playing around with secure boot, with the ultimately goal of setting it up on my laptop. I experimented in a libvirt/qemu VM and to my surprise a custom secure boot setup is rather easy (the Secure Boot page on the Arch Wiki suggests quite the contrary), thanks to dracut and a fairly recent tool named sbctl which just recently had it’s first release.


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