I have just made the switch over to Incus and let me preface this with a big thank you to all contributors who have seen to making the process as painless as possible. Needless to say, the conversion went without a hitch 
That being said, there’s a little pet project of mine that I have been trying to get off the ground for quite a while now without final success - streaming a headless wayland container via Sunshine.
Background
There is a long history of running GUI apps in the container on the host (most recently this thread), which is not what I am trying to achieve since the host is purely accessed via SSH and is neither running a X nor wayland server. There is another topic where a user was having some success starting a container-only X-server and this is pretty much my direction using wlroots and sway in this case.
Setup info
I’m currently using Incus 5.0 from Debian Testing on Bookworm running on a Hetzner dedicated server. The container to be streamed is running Debian 12 as well with the following configuration -
container (device) configuration:
devices:
desk.igpu:
gid: "44"
pci: "0000:00:02.0"
type: gpu
desk.input-joystick:
gid: "1000"
path: /dev/input/event7
required: "false"
source: /dev/input/event7
type: unix-char
uid: "1000"
desk.input-keyboard:
gid: "1000"
path: /dev/input/event6
required: "false"
source: /dev/input/event6
type: unix-char
uid: "1000"
desk.input-mouse:
gid: "1000"
path: /dev/input/event4
required: "false"
source: /dev/input/event4
type: unix-char
uid: "1000"
desk.input-touchscreen:
gid: "1000"
path: /dev/input/event5
required: "false"
source: /dev/input/event5
type: unix-char
uid: "1000"
desk.tty0:
gid: "1000"
path: /dev/tty0
source: /dev/tty0
type: unix-char
uid: "1000"
desk.tty1:
gid: "1000"
path: /dev/tty1
source: /dev/tty1
type: unix-char
uid: "1000"
desk.uinput:
gid: "1000"
path: /dev/uinput
type: unix-char
uid: "1000"
desk.wireguard:
connect: udp:10.200.200.2:60820
listen: udp:external-ip:60820
nat: "true"
type: proxy
Since Sunshine creates virtual input devices via uinput, I have forwarded “/dev/uinput” accordingly and made sure that the resulting input devices are added as well (the configuration is rather static since no devices are connected / disconnected from the server). Side-node: unix-hotplug does not add any devices to the container, but unix-char seems to work.
You’ll also find the iGPU as well as a port for WireGuard access forwarded to the container (with wayvnc and Sunshine bound to the VPN).
sway is started with the following script after logging in to the container via ssh. “libinput” as a backend works when forwarding “/dev/tty0” and “/dev/tty1”, though some errors (*) can be seen during startup. Alternatively, I can start with libinput using the “incus console [container]” command and then just running the below script script. The “headless” backend accesses a virtual display created by sway.
sway-startup.sh script:
#!/bin/bash
export DESKTOP_SESSION="sway"
export XDG_CURRENT_DESKTOP="sway"
export XDG_DATA_DIRS="/usr/local/share:/usr/share:/var/lib/flatpak/exports/share:/home/desk/.local/share/flatpak/exports/share"
export XDG_SESSION_DESKTOP="sway"
export XDG_SESSION_TYPE="wayland"
export WLR_BACKENDS="headless,libinput"
export WLR_LIBINPUT_NO_DEVICES="1"
exec /usr/bin/sway -c /home/desk/.config/sway/desk
(*) errors when starting sway with libinput backend via ssh:
Jan 29 15:59:24 desk ssh[166884]: 00:00:00.001 [ERROR] [wlr] [libseat] [common/terminal.c:208] Could not set VT mode to enable process switching: Operation not permitted
Jan 29 15:59:24 desk ssh[166884]: 00:00:00.001 [ERROR] [wlr] [libseat] [common/terminal.c:248] Could not set KD keyboard mode to disabled: Operation not permitted
Jan 29 15:59:24 desk ssh[166884]: 00:00:00.001 [ERROR] [wlr] [libseat] [common/terminal.c:275] Could not set KD graphics mode to graphics: Operation not permitted
What works?
I tried connecting to the session using both, wayvnc and Sunshine with the former working pretty much flawlessly (*) and the latter only showing the stream without mouse and keyboard input being possible. This in itself is quite amazing imho since accelerated video (h.265 encoding for the Sunshine stream) and 3D seem to work without issues.
(*) Why not just use wayvnc then? The issue here is that while the stream uses h.264 encoding, the VNC screen capture method itself is way too slow to deliver full screen video or any high speed motion output such as scrolling a web page at higher resolutions. It also currently lacks sound support (the developer is looking into options), which, while not critical, would be nice to have.
wayvnc uses the wlr-virtual-{pointer,keyboard} protocol to add its virtual input devices, which are listed properly when querying with “swaymsg -t get_inputs”. Also, any game controller connected via Sunshine can be used since those are not managed by sway but accessed directly. I only tested with “Tuxkart”, so the controller may or may not be picked up by other titles, but that is not an issue for now.
What doesn’t?
This is not the case for Sunshine though, which creates its devices via uinput. The /dev/input/eventX entries get added correctly on the host, can be forwarded to the container and confirmed working by using e.g. evtest, but do not show up as libinput devices and consequently can’t be used to control the sway session.
I’d be grateful for any clues as to what might be missing here, if this can be made to work at all with the setup described above. This is not purely an incus issue, but there are probably quite a few people around who have tried something along those lines and might be able to provide input
