# main-desktop Custom [Bazzite DX](https://github.com/ublue-os/bazzite-dx) image for my desktop, built with [BlueBuild](https://blue-build.org), published to GHCR by GitHub Actions, and signed with cosign. - **Base:** `ghcr.io/ublue-os/bazzite-dx-nvidia` — Bazzite DX, KDE Plasma, **NVIDIA open kernel modules**. There is no separate `-open` DX image anymore: DX NVIDIA is open-driver-only, which is exactly what the RTX 5090 (Blackwell) requires. Current stable ships driver **610.x** (open). - **Pinned** to Fedora 44 via `image-version: stable-44` in [recipes/recipe.yml](recipes/recipe.yml). No surprise major upgrades; bump to `stable-45` deliberately. - **This image layers almost nothing.** The base already includes Steam and the gaming stack, Flatpak, Docker CE + CLI, Podman, VS Code, Homebrew, **and nvidia-container-toolkit with automatic CDI setup** (`ublue-nvctk-cdi.service` regenerates `/etc/cdi/nvidia.yaml` each boot). What this recipe adds: the cosign signature-verification policy and a declarative first-boot Flatpak set. That's it — by design. Why BlueBuild instead of the raw Containerfile template: with the container toolkit already in-image, the whole custom layer is "install these Flatpaks on first boot + trust my signature", which the `default-flatpaks` and `signing` modules express declaratively in ~40 lines of YAML — no hand-rolled first-boot systemd unit needed. ## One-time setup (before first push) 1. Create a GitHub repo and push this directory to it (`main` branch). 2. Generate the signing keypair in the repo root (**press Enter for an empty password** — the build action cannot use an encrypted key): ```bash cosign generate-key-pair ``` 3. Store the private key as an Actions secret and commit only the public half: ```bash gh secret set SIGNING_SECRET < cosign.key git add cosign.pub && git commit -m "Add cosign public key" && git push ``` `cosign.key` is git-ignored — never commit it. 4. The workflow (`.github/workflows/build.yml`) now builds on every push, on manual dispatch, and daily at 06:00 UTC (so base-image updates flow through automatically — this is what makes the image self-updating). Images publish to `ghcr.io//main-desktop`. 5. If the GHCR package ends up private, make it public in the package settings (Packages → main-desktop → Package settings → Change visibility), or rebasing will fail to pull. ## Rebasing the desktop onto this image From the existing Bazzite install, rebase in two steps — first unsigned (this installs the image, which contains the signing policy and public key), then signed: ```bash # Step 1: unsigned rebase, then reboot rpm-ostree rebase ostree-unverified-registry:ghcr.io//main-desktop:latest systemctl reboot # Step 2: switch to the signed ref, then reboot rpm-ostree rebase ostree-image-signed:docker://ghcr.io//main-desktop:latest systemctl reboot ``` After step 2, every update is signature-verified. `:latest` is fine here — the Fedora pin lives in the recipe, so `latest` never crosses a major until the recipe says so. Roll back anytime with `rpm-ostree rollback` (or pick the previous deployment in the boot menu). ## Install-time checklist 1. **Driver sanity:** `nvidia-smi` reports driver **≥ 580** (currently 610.x) and the RTX 5090 is listed. Confirm open kernel modules: `modinfo -F license nvidia` should say `Dual MIT/GPL` (the proprietary module says `NVIDIA`). Blackwell only works on the open modules. 2. **Signature:** verify the published image against the committed public key: ```bash cosign verify --key cosign.pub ghcr.io//main-desktop:latest ``` 3. **Deployment:** `rpm-ostree status` shows the booted deployment is `ostree-image-signed:docker://ghcr.io//main-desktop` and the base version matches a recent build. 4. **Flatpaks:** the first-boot service installs the whole list below; give it a few minutes on first login (it notifies when done). Check with `flatpak list --system`. 5. **Docker group:** run `ujust dx-group` (adds you to `docker` and friends), then log out/in. 6. **GPU in containers:** see the section below — run the one-liner test. ## GPU in containers (CUDA on the 5090) `nvidia-container-toolkit` is already in the image and a boot service generates the CDI spec automatically. CDI is the shipped mechanism: ```bash # Podman — works out of the box: podman run --rm --device nvidia.com/gpu=all docker.io/nvidia/cuda:12.8.0-base-ubuntu24.04 nvidia-smi # Docker — CDI device syntax also works on current Docker CE: docker run --rm --device nvidia.com/gpu=all nvidia/cuda:12.8.0-base-ubuntu24.04 nvidia-smi ``` If you want the classic `docker run --gpus all` syntax, that needs a one-time runtime hookup (this writes to `/etc/docker/daemon.json`, which is mutable and survives updates): ```bash sudo nvidia-ctk runtime configure --runtime=docker sudo systemctl restart docker ``` ## First-boot Flatpaks Installed system-wide from Flathub by the `default-flatpaks` module. All IDs verified against Flathub (2026-07). **Official / verified listings:** Bambu Studio, Bitwarden, Discord, Firefox, Thunderbird, FreeCAD, GIMP, HandBrake, LibreOffice, Moonlight, PCSX2 (`net.pcsx2.PCSX2` — the official build), Podman Desktop, Warzone 2100, XIVLauncher (`dev.goats.xivlauncher`). **Community / unverified listings — know what you're running:** | App | ID | Note | |---|---|---| | GitHub Desktop | `io.github.shiftey.Desktop` | Community Linux fork; the "shiftey" spelling is the real ID | | MakeMKV | `com.makemkv.MakeMKV` | Community packaging of the proprietary app | | GeForce NOW | `io.github.hmlendea.geforcenow-electron` | **Unofficial** Electron wrapper, not an NVIDIA product | | VLC | `org.videolan.VLC` | No verified badge on Flathub (still the VideoLAN-maintained build) | | Godot | `org.godotengine.Godot` | No verified badge on Flathub | **GeForce NOW on the 32:9 monitor:** the service only streams 16:9 (and some 21:9) aspect ratios, so expect pillarboxing at 5120x1440 — that's a service limitation, not a config problem. ## Post-install steps (manual by design — don't automate these) ### PIA VPN — native WireGuard, not the app The PIA desktop app installs into `/usr` and breaks on the read-only filesystem. Skip it: 1. Log in at PIA's [OpenVPN config generator](https://www.privateinternetaccess.com/pages/ovpn-config-generator) (or generate a WireGuard config via their API/support flow) and download configs for your preferred regions. 2. KDE **System Settings → Network → Connections → Add (+) → Import VPN connection…**, pick the downloaded file, and enter your PIA credentials. 3. This is plain NetworkManager — it lives in `/etc`, survives every update, and gets a connect/disconnect toggle in the system tray. ### Microsoft Teams — PWA via Edge No native Linux client. Install **Microsoft Edge specifically** (corporate conditional access / Intune compatibility): `flatpak install flathub com.microsoft.Edge`, sign in to , then menu → **Apps → Install this site as an app**. ### Claude desktop — PWA No official Linux app. Open in Edge (or any Chromium browser) and use **Install this site as an app** the same way. ### Proton-GE Already handled by Bazzite: use the preinstalled **ProtonUp-Qt** GUI (or browse `ujust` — run `ujust` with no arguments to list recipes). Don't install anything extra. ## Node / toolchains — not in the image Node, npm, etc. are deliberately **not layered**. Use per-project versions instead: ```bash brew install mise # Homebrew ships in the base image mise use node@22 # per-project .mise.toml; `mise use -g node@22` for a global default ``` (Plain `brew install node` also works if you just want one global Node.) ## Display note The 49" 32:9 (5120x1440) ultrawide needs nothing at the image layer. Post-install: set scale and refresh rate in KDE System Settings → Display; KDE's window tiling (Meta+drag, or a tiler like Polonium) is worth setting up at this width. VMs are remote via Remmina — there is intentionally no local hypervisor tooling in this image. ## Maintenance - **Change the Flatpak list / packages:** edit [recipes/recipe.yml](recipes/recipe.yml), push, and the next update picks it up. (Removing an app from the list does not uninstall it from the machine; `flatpak uninstall` it once by hand.) - **Jump Fedora majors:** change `image-version: stable-44` → `stable-45` in the recipe when ready, push, then update normally. - **Check build status:** the Actions tab; builds also run nightly, so a broken base shows up there before it reaches the machine.