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# mibook: choose terminal-only vs desktop at boot
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## Goal
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Let mibook offer a choice, each time it boots, between the normal KDE desktop
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and a terminal-only ("server") mode with no graphical session — decided at
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boot, without rebuilding the system.
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## Background: why the first attempt failed
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The first implementation booted mibook to a text console by default
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(`systemd.defaultUnit = "multi-user.target"`, display manager not started) and
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provided a `desktop` command to start KDE on demand. On real hardware this
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locked the machine out:
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- **No SSH.** mibook is WiFi-only and its WiFi credentials are stored per-user
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in KWallet ("agent-owned"). NetworkManager only receives the password once a
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desktop session is running, so a headless boot never joins the network and
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the machine has no IP — nothing to SSH into.
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- **No usable console.** The boot appeared to "hang" with no login prompt:
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`NetworkManager-wait-online` stalled waiting for a network that never came
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up, and the `getty` login prompt on tty1 was buried under later service
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messages.
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Conclusion: a headless WiFi laptop cannot be reached remotely, and the plain
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console was hard to use. The design must (a) keep the desktop as the reliable
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default, (b) make the terminal path a deliberate, self-sufficient choice, and
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(c) not depend on the network being up.
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## Behavior
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- The **default GRUB entry** boots straight into KDE — unchanged from the
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known-working baseline.
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- A **separate GRUB entry, `mibook (terminal)`** (a NixOS *specialisation*),
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boots to a text console with **autologin** for `finn`. From there the user
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can work in the shell or run `desktop` to bring KDE up (via SDDM).
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- The choice is made in the GRUB menu at boot — matching the original request
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to "decide each time I boot."
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- Booting never stalls on the network.
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### Known limitation (documented, not fixed in config)
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In terminal mode WiFi will not connect on its own, because the password is
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stored per-user in KWallet. To reach mibook over SSH from terminal mode, the
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user must first save the WiFi as a **system** connection in KDE:
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network settings → the WiFi network → "All users may connect to this network".
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Until then, terminal mode is local-console-only. This is a one-time manual
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step outside the scope of the Nix config.
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## Implementation
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### `machines/mibook/configuration.nix`
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- Add a NixOS specialisation `specialisation.terminal.configuration`:
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- `system.nixos.tags = [ "terminal" ];` — labels the generated boot entry.
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- `systemd.defaultUnit = lib.mkForce "multi-user.target";` — boots to the
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text console. `graphical.target` is what pulls in the display manager (via
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its embedded `Wants=display-manager.service`), so defaulting to
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`multi-user.target` leaves SDDM installed but not started at boot.
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- `services.getty.autologinUser = "finn";` — guarantees a usable shell on
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the console instead of a login prompt that can scroll off screen.
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- A `desktop` command via
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`pkgs.writeShellScriptBin "desktop" "exec sudo systemctl start display-manager.service"`
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in `environment.systemPackages`, to start KDE on demand.
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- Add `systemd.services.NetworkManager-wait-online.enable = false;` (applies to
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both the default and terminal boots) so boot never stalls waiting for the
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network.
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### Reverted from the first attempt
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- `modules/environments/kde-desktop/default.nix` — remove the `startOnBoot`
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option and its `mkMerge`/`mkIf` machinery; back to the original profile that
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simply enables SDDM + Plasma 6.
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- `machines/mibook/environments.nix` — remove `kde-desktop.startOnBoot = false;`
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(back to just `kde-desktop.enable = true;`).
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## Why a specialisation
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A specialisation generates a second boot-menu entry automatically from a
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modified copy of the configuration. It is the idiomatic NixOS mechanism for a
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boot-time choice and avoids fragile hand-written GRUB `extraEntries` that would
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need to track kernel/initrd paths across generations. The default entry remains
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byte-for-byte the working desktop configuration.
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## Testing / verification
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- `nix build '.#nixosConfigurations.mibook.config.system.build.toplevel'`
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builds both `nixos-system-mibook` and `nixos-system-mibook-terminal`.
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- Verified on the built closures:
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- Parent `default.target` → `graphical.target`; no console autologin
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(identical to the pre-change baseline).
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- Specialisation `default.target` → `multi-user.target`; tty1 getty wrapper
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contains `--autologin finn`; `desktop` present in the system profile.
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- `NetworkManager-wait-online` disabled in both.
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- Post-`switch` manual check on mibook: default GRUB entry boots to KDE; the
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`terminal` entry boots to an autologged-in console; running `desktop` there
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starts SDDM and a working Plasma session.
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## Trade-offs
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- Autologin on the terminal console means physical access grants a shell
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without a password. Acceptable for a personal laptop the user controls; the
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desktop (default) boot is unaffected.
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- `desktop` relies on `sudo`; the user has sudo access, so no extra config is
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required.
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finn.markwitz