Requirements

The host machine

Linux only. The node agent runs with network_mode: host, because WebRTC has to send UDP from the host’s own network namespace. Docker Desktop on macOS and Windows cannot do that, so media will not work there at all. Any systemd distribution with Docker should be fine. Fedora 44 is what the install is verified on.

Docker Engine with Compose v2.20 or newer.

About 20 GB of disk for the images, plus room for game containers and save data.

Fedora's default root volume is too small

A stock Fedora install gives the root logical volume 15 GB. Grow it first with lvextend and xfs_growfs.

CPU and RAM matter less than you would think, because the GPU does the encoding. 8 vCPU and 32 GB is what the install is measured on. Less works.

GPU

Vendor	Encoder	Status
AMD	Vulkan Video	Verified.
NVIDIA	Vulkan Video	Verified.
Intel	Vulkan Video or VA-API	Untested. Both paths exist and should work; nobody has run it.
None	openh264, in software	Proves the install. Too slow and too ugly to play on.

NVIDIA hosts need the driver plus nvidia-container-toolkit, registered with Docker once:

sudo nvidia-ctk runtime configure
sudo systemctl restart docker

A CUDA-only NVIDIA install is not enough

The CUDA packages alone leave you without EGL and without 32-bit GL. The compositor needs EGL, and native 32-bit game binaries need the 32-bit libraries. Quasar can work around this by provisioning a driver volume, but installing the full driver stack is better. See Install and startup problems.

Kernel

/dev/uinput has to exist and be writable. That is how Quasar creates the virtual keyboard, mouse and gamepads.

sudo modprobe uinput
echo uinput | sudo tee /etc/modules-load.d/uinput.conf

The compose file declares the device and the input cgroup rule, so loading the module is all you do.

One sysctl

Raise the default UDP send buffer on every machine that streams:

echo 'net.core.wmem_default=2097152' | sudo tee /etc/sysctl.d/99-quasar.conf
sudo sysctl --system

This one is not optional and nothing applies it for you. The media path sends through libnice, which never calls setsockopt(SO_SNDBUF), so its UDP sockets inherit the kernel default of 208 KB. A keyframe burst at 8 Mbps overflows that, the kernel drops the overflow silently, and the bitrate estimator reads the loss as network congestion and throttles the stream. The symptom looks exactly like a bad network.

Firewall

The control plane’s ports are published through Docker, which routes them past the host firewall, so they need no rule. The node agent is different: it uses the host network directly, and a default-deny firewall will drop its WebRTC UDP. See Ports and endpoints.

SELinux can stay enforcing. That is verified, with no denials.

The client device

Anything running a recent Chrome or Chromium browser that can reach the GPU host over the network.

Chrome is what Quasar is validated against. Keyboard Lock, which is what lets Escape reach the game instead of leaving fullscreen, is Chromium-only. Firefox and Safari are untested. See Browser support.

The page has to be served over HTTPS. Gamepads, Keyboard Lock and microphone capture all need a secure context, so a plain HTTP deployment loses all three. Quasar generates its own certificate on first boot, so this is handled for you. See HTTPS and certificates.

Network

Your client needs to reach the GPU host directly, on the same LAN or over a VPN. Media is WebRTC between the browser and the host, and it does not travel through a reverse proxy. Putting the login page on the internet does not put the stream there. See Reaching Quasar remotely.