ja
9d06a71f71
- Add greetd role with tuigreet greeter (3 packages, 4.9MB) - Replace SDDM as display-manager.service with greetd - Add ADR 0003 documenting migration rationale - Rename hyprland task: "register session in SDDM" -> "register Wayland session desktop entry" - Add display_manager variables to vars/main.yml - Add greetd role to workstation.yml - Update setup.md timestamp
96 lines
3.0 KiB
Markdown
96 lines
3.0 KiB
Markdown
---
|
|
description: >-
|
|
Replace SDDM (Qt-based graphical display manager) with greetd + tuigreet
|
|
for a minimal, Wayland-first login experience with zero heavy GUI dependencies.
|
|
status: accepted
|
|
date: 2026-05-20
|
|
replaces: SDDM as display-manager.service
|
|
---
|
|
|
|
# 0003: SDDM to greetd Migration
|
|
|
|
## Context
|
|
|
|
The workstation uses Hyprland as the primary Wayland compositor. SDDM was
|
|
pulled in as the display manager with significant Qt dependencies (~50+
|
|
transitive packages). For a single-user dev workstation running Hyprland,
|
|
this is unnecessary overhead — heavy, slow-booting, and over-engineered for
|
|
the use case.
|
|
|
|
SDDM provides: graphical login prompt, session selection, PAM authentication.
|
|
All three can be achieved with far lighter tools.
|
|
|
|
## Decision
|
|
|
|
Migrate from SDDM to greetd + tuigreet.
|
|
|
|
- **greetd**: minimal display manager daemon, designed for Wayland first-class.
|
|
- **tuigreet**: TUI greeter with time display, user remembering, session
|
|
discovery from `/usr/share/wayland-sessions/` and `/usr/share/xsessions/`.
|
|
|
|
### What changed
|
|
|
|
| Before | After |
|
|
|--------|-------|
|
|
| sddm.service (display-manager) | greetd.service (display-manager) |
|
|
| Qt5/Qt6 dependency chain | greetd + greetd-tuigreet (3 packages, 4.9MB) |
|
|
| /etc/sddm.conf | /etc/greetd/config.toml |
|
|
| Graphical login screen | Text-based TUI login screen |
|
|
| Heavy PAM surface | Standard PAM chain (system-local-login) |
|
|
|
|
### Ansible changes
|
|
|
|
- Added `greetd` role: installs packages, configures config.toml from template,
|
|
enables greetd as display-manager.service
|
|
- Hyprland task renamed: "register session in SDDM" -> "register Wayland session
|
|
desktop entry" (no functional change, just accurate naming)
|
|
- vars/main.yml: added `display_manager_package`, `display_manager_greeter`,
|
|
`display_manager_config` variables
|
|
|
|
### Configuration
|
|
|
|
```toml
|
|
[terminal]
|
|
vt = 1
|
|
[default_session]
|
|
command = "tuigreet --time --remember --asterisks --cmd Hyprland"
|
|
user = "greeter"
|
|
```
|
|
|
|
### Rationale
|
|
|
|
1. **Wayland-native**: greetd handles Wayland sessions cleanly without X
|
|
compatibility layers
|
|
2. **Minimal**: 3 packages vs Qt dependency chain; <5MB vs ~500MB
|
|
3. **Maintained**: Rust codebase, clean TOML config, Arch repos (no AUR)
|
|
4. **AI-agent friendly**: TOML config is trivially parseable/modifiable;
|
|
clean systemd service with structured journalctl output
|
|
5. **Simplicity principle**: maximizes work not done
|
|
|
|
## Consequences
|
|
|
|
### Positive
|
|
|
|
- Faster boot (no Qt/Xorg init)
|
|
- Smaller attack surface
|
|
- Less disk usage
|
|
- No Qt dependencies to maintain
|
|
- Clean systemd service management
|
|
|
|
### Negative
|
|
|
|
- No graphical login (only a limitation if multi-user GUI switching is needed)
|
|
- SDDM themes not available (not a requirement for this workstation)
|
|
- Tuigreet has fewer visual customization options
|
|
|
|
### Migration path back
|
|
|
|
```bash
|
|
sudo systemctl disable greetd
|
|
sudo systemctl enable sddm
|
|
sudo ln -sf /usr/lib/systemd/system/sddm.service /etc/systemd/system/display-manager.service
|
|
```
|
|
|
|
Reversible with zero data loss — the hyprland.desktop session entry is
|
|
unchanged and works with both DMs.
|