Spaces

A Space is a separate launcher sign-in, game library and set of saves on one Linux gaming PC. Each Space runs Steam, Heroic Games Launcher or Lutris, so one player can keep a Steam account in theirs while another plays their Epic and GOG games through Heroic. Two players can use their own Spaces at the same time, one person can keep a Space on a server without a monitor, or a handheld and a TV can share one Space at different times.

Spaces are a preview. One limit shapes everything below: the host runs one Space at a time. The gaming runtime is published, so Host Setup can download it, and which runtime you get depends on your graphics card. The NVIDIA runtime has been played end to end on an NVIDIA host. The other one, for AMD and Intel graphics, has never been run on that hardware by anyone here, so treat it as untried rather than supported.

Spaces are optional. If you stream your usual desktop and games today, keep using the Library in Nova; nothing here is required for that, and you do not need Docker. Spaces or regular streaming puts the two side by side.

Example with sample player and device names.

What you need

Component	Purpose
Polaris RPM, Arch package or DEB	Runs the host, pairing, settings and streaming
Docker Engine on that host	Runs the isolated gaming environments
Polaris gaming runtime image	The launcher and the software that runs inside each Space, one image per launcher, downloaded by Docker from GitHub Container Registry
Nova on your device	Opens the stream and sends your controls

The launcher, its 32-bit libraries and the gaming userspace live inside the runtime image, so the host does not need Steam, Heroic or Lutris installed. The host still needs Polaris, Docker, its GPU driver and input permissions. The NVIDIA runtime borrows this PC’s own driver files, so it works with whichever NVIDIA driver is loaded; NVIDIA driver files explains what it reads. Older NVIDIA runtimes, built for drivers 610.57.04 and 615.71.09, keep running the Spaces made on them.

The native packages ship the setup UI, the controller, the host policy files and the polaris-spaces-setup helper. There is no supported image that runs the whole Polaris host inside Docker, and no Unraid template.

Host Setup

Open Spaces in the Polaris console, beside Devices, and expand Host Setup. It runs eight checks on the PC hosting Polaris, whichever device you opened the page from, and each failing check links the section of this guide that fixes it. Select Recheck Setup after every terminal step. A configured host keeps the section collapsed.

Two checks can be fixed from the page itself. Polaris access to Docker offers Give Polaris access to Docker, and Spaces security support offers Install security support. Either button opens a password prompt on the screen of the PC that runs Polaris, so someone signed in at that PC’s desktop approves the change. From another device you can start the request, but only someone at the PC can approve it. The terminal steps under each check do the same thing.

Polaris asks for one change at a time and closes the prompt if nobody approves it within five minutes. While a change runs, Space launches and changes to Spaces wait. Polaris does not ask, and says why, on an image based system, when the native package’s helper or its polkit policy is missing, when nobody is signed in at the PC’s desktop, or while a Space, a stream or the first Space setup is still active.

Prepare Docker from Spaces

If Docker Engine passes and Polaris access to Docker needs attention, select Give Polaris access to Docker and approve the password prompt on the Polaris host’s screen. Polaris starts the system Docker service, sets it to start with the PC, and adds the account Polaris runs as to the docker group. A Polaris that is already running keeps the groups it started with, so the check then asks you to restart the PC. After the restart, select Recheck Setup.

From a terminal on the Polaris host instead:

1. If Docker Engine needs attention, install it with your distribution’s steps below.
2. Start the system Docker service, then grant Docker access to the Linux account running Polaris. For a service installation that account may differ from your terminal account; grant it to the service account.
3. Save your work, stop streams and restart the PC, so Polaris starts with the new group.
4. Select Recheck Setup.

Docker group access gives that account administrator-level control over the host. Grant it only to a trusted account; Docker’s post-installation instructions explain why.

If Docker Engine passes but Polaris access to Docker fails, confirm that the system daemon is running and that the Polaris process received the new group membership. Docker Desktop, remote Docker contexts and rootless Docker are not the supported engine in this preview.

Fedora

sudo dnf config-manager addrepo --from-repofile https://download.docker.com/linux/fedora/docker-ce.repo
sudo dnf install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin
sudo systemctl enable --now docker

If you already have a container engine or hit a package conflict, read the Docker Fedora guide before replacing packages. Spaces never removes existing container software.

Arch Linux

sudo pacman -Syu docker

If the update installed a new kernel, save your work and restart the host before starting Docker; signing out alone does not load the new kernel, and Docker can fail to start when the running kernel no longer has its network modules. Then:

sudo systemctl enable --now docker

The Arch Docker documentation covers distribution-specific configuration.

Ubuntu

Follow the Docker Ubuntu guide to add Docker’s repository key and package repository, then install the engine. Return to Spaces and select Recheck Setup.

Bazzite, SteamOS and other system images

The package commands above do not apply, and the preview does not automate Docker on these systems. Use your distribution’s supported installation method, and do not disable filesystem protection to follow instructions written for another distribution.

Gaming runtime account

The current runtime requires the Linux account running Polaris to have user and group ID 1000, which is the first account created on most installations. The Gaming runtime account check says whether this host qualifies.

Do not change an existing account’s ID to work around this; it breaks file ownership across the whole account. Run Polaris under an account that already has that ID, or wait for a runtime that lifts the limit.

Controller access

Polaris creates virtual controllers, keyboards and mice for a Space through /dev/uinput and /dev/uhid. When Controller and input access fails, run the host setup that grants them:

sudo -H polaris --setup-host

then restart Polaris and select Recheck Setup. Doctor & Support shows the same access with its reason.

Graphics access

A Space needs a render node the Polaris account can open. When Graphics device access fails, check that the GPU driver is installed and that the account is in the group that owns /dev/dri/renderD* (usually render or video); Doctor & Support names the node it tried. Hardware encoding is checked again when the Space starts.

Prepare Spaces security support

On hosts with SELinux, the Spaces security support check verifies that SELinux is enforcing and that the dedicated policies and input rule are installed at the matching version. Hosts without SELinux need only the Steam seccomp file, which the native package includes.

On a mutable Fedora installation:

1. Install the tools that compile against your host policy, in a terminal on the Polaris host:

   sudo dnf install selinux-policy-devel container-selinux make

2. Finish your games and stop Space streams.
3. Select Install security support on the check and approve the password prompt on the Polaris host’s screen. Polaris stays open, and the check is read again when the helper finishes.

Without anyone at the host’s desktop, run the helper from a terminal instead:

1. Quit Polaris. If it runs as a service, stop the service first.
2. Run the helper from the native package:

   sudo -H /usr/bin/polaris-spaces-setup install

3. Start Polaris, return to Spaces and select Recheck Setup.

The helper installs the worker policy, the reserved controller policy, a version marker and the reserved input rule. It reloads policy and udev rules without changing enforcement or relabeling controllers, and it does not install Steam, change drivers, start Docker or restart Polaris. If it is interrupted, run the same command again. Policies you installed by hand, and an input rule that differs from the packaged one, are reported with the command that clears them rather than replaced. An input rule identical to the packaged one is adopted.

If the helper refuses, its message names what it found and prints the command that clears it:

• “Spaces setup found SELinux modules it does not manage” lists each copy of a module with one of the helper’s names that sits at another priority, is disabled or was installed another way, for example a copy installed by hand, and prints the command that removes those copies, such as sudo semodule -X 400 -r polaris_multiseat_input polaris_nvidia_worker. Run it, check sudo semodule -lfull | grep polaris_, then run the install again. libsemanage may print “Failed!” while removing; trust the list, not the message.
• “Spaces setup found SELinux modules at priority 200 that it has no record of installing” means the policies stayed installed after the helper’s records in /var/lib/polaris/spaces-security were deleted. Remove them with the printed command and run the install again.
• “Quit Polaris and stop Spaces streams before changing security setup.” names each Polaris process still running as name (pid N), a second instance included, a Space that is still running with its process count, and the Spaces input devices still present. systemctl status PID shows which service started a process. Stop it and retry. From the button the message starts “Stop Spaces streams and quit any other Polaris”: the Polaris that asked stays open, and everything else still counts.
• “is not owned by this setup and differs from the rule this package ships” means /etc/udev/rules.d/97-polaris-multiseat-input.rules was placed there by hand or by an older build. Move it aside as the message shows and run the install again. A rule identical to the one the package ships is adopted instead: the install says so, records it as its own, and remove deletes it later like any rule the helper installed.
• “changed after this setup installed it” or “is missing” means a policy or the input rule the helper installed was changed or deleted since. The message prints the command that restores the installed copy from /var/lib/polaris/spaces-security. Run it, then the same helper command again.

polaris-spaces-setup status shows readiness. sudo -H /usr/bin/polaris-spaces-setup remove removes only what the helper owns, after Polaris and every Space have stopped; it never deletes player homes. Remove the policies before uninstalling the package if you no longer need them: package removal alone leaves them installed with nothing left to remove them, and Uninstall Polaris, or start over has the full order. Package installation and removal never change live SELinux policy. Other SELinux distributions need the compatible development interfaces and the container reference policy; system images are not supported by the helper in the preview.

Download the gaming runtime

The Gaming runtime check picks the runtime this PC needs from the ones this Polaris build approves: the NVIDIA runtime, which borrows this PC’s driver, when an NVIDIA driver is loaded, otherwise the runtime for AMD and Intel graphics. It asks Docker for that exact image and verifies it against the build. Downloading it here is optional; preparing your first Space downloads it too.

• Waiting for runtime means this build has no approved gaming runtime yet. Nothing on this PC can change that, so the check stays out of the count.
• Not downloaded means the runtime this PC needs is not on it yet. Once the host checks above pass, select Download. The download is several gigabytes and shows no percentage. You can leave Spaces and come back; the host keeps the download running. Stop download ends it, and Docker keeps verified layers for the next attempt.
• Checked means the runtime is downloaded and verified. Preparing your first Space then starts without downloading it again.
• Needs attention without a button means no runtime in this build fits this PC. When the check names an NVIDIA driver version, install that version, restart the PC, then recheck. When the build’s runtime is for other graphics than this PC has, wait for a build that includes one for yours.
• Needs attention with Retry download means Docker did not finish answering, or holds an image under the approved reference that does not match this build. Retry. If it keeps failing, check that Docker is running and open Doctor & Support.

A download runs on the host like first-Space setup, one job at a time. It never prepares a Steam home or changes Spaces configuration, and Polaris never removes or replaces an image. If Polaris restarts during a download, select Download again; Docker reuses the layers it kept. On a host whose Spaces are already configured, the check still reports the runtime but offers no download.

Prepare your first Space

Once the host checks pass and a runtime is offered:

1. Under Set up your first space, enter a name such as Living room. If more than one runtime is offered, choose the variant for your graphics hardware; an older NVIDIA variant names the driver it was built for.
2. Select Download and prepare. If the Gaming runtime check shows Checked, preparation starts without a download. Otherwise the download is several gigabytes. You can leave Spaces and come back; the host keeps the job. Polaris cannot show a percentage for it.
3. Stop setup is available while the runtime downloads; Docker keeps verified layers for the next attempt. Once Steam home preparation begins, wait for it to finish.
4. When the home is prepared, choose its Graphics card and select Enable Spaces. Polaris saves its configuration without starting a game. This first setup allows one Space at a time; hosts configured by hand keep their own budget.
5. Save any running game, then select Restart Polaris and finish setup. Restarting disconnects every stream. Reconnect and return to Spaces.
6. Under Device Access, tick your paired Nova device in the new Space’s column. With one Space it opens that Space first; Default Space changes where each device opens first.

Steam home prepared means storage was saved. Configuration saved means a restart is still required. Neither is a game or controller test yet; that comes in Play in a Space.

Recover an interrupted setup

• Reconnect to setup re-reads the job without changing it. Use it first after a dropped connection.
• Retry setup checks the original request and its saved home. It never creates a second home or copies another player’s sign-in.
• If Polaris restarts, the job does not resume on its own. Return to Spaces and retry it.
• If the runtime you started with is no longer offered by this build, the job cannot be retried; your player data stays where it is.
• If the setup journal could not be secured, Spaces shows recovery required and names the retained image and reference. Polaris keeps uncertain resources for recovery instead of deleting or adopting them. Restart Polaris after saving your work; if it persists, open Doctor & Support and keep the existing player data while diagnosing.
• If no accessible graphics card matches the runtime, the prepared home waits. Fix graphics access and recheck.

Configuration is retried with the same graphics selection. A changed or inaccessible GPU needs attention; Polaris does not silently choose another.

Add a Space on a configured host

1. Stop every Space stream. Creating, renaming, removing or restoring a Space and changing any device’s access all reload the host’s Space catalog, so they wait for the streams to end.
2. Select Create a Space, give it a recognisable name, a player or a room, and choose its Launcher: Steam, Heroic or Lutris. The list shows the launchers this PC can make a Space for.
3. The first Space of a launcher downloads that launcher’s gaming runtime, a few gigabytes, and the page says so before you create it and follows the download. Later Spaces of the same launcher copy the runtime of one you already have and download nothing. Every new Space starts with its own sign-in, saves and settings; nothing is copied from another player.
4. Wait for the creation to be confirmed. After a dropped connection use Check creation status or Retry creation; both check the same request. Returning to Spaces in the same browser tab restores an unfinished request without submitting it again.
5. Give a device access, below, then refresh the library in Nova.

Give a device access

Device Access is one table. Each row is a handheld, TV or computer paired with Polaris, each column is a place it may play, and the last column is where it opens first. On a narrow window the same rows show as one card per device.

• Tick a Space’s column to let a device open that Space. A device with more than one place to play picks between them in Nova with Change Space.
• The Desktop column adds Desktop, this PC’s usual desktop and apps, as one more choice beside a device’s Spaces.
• The Every device row changes a whole column at once: All lets every device in, and None asks first, then removes every device. Each is one change, where ticking devices one by one restarts Spaces every time.
• Give Desktop Access with a Space makes a tick in a Space’s column give the device Desktop as well. It applies to the ticks you make from then on; devices you have already set up stay as they are.
• Default Space sets where a device opens first: one of the Spaces it may open, or Desktop once it has Desktop Access. Choose it and select Save. Saving never changes which Spaces or Desktop a device may open. A device with one place to play has nothing to choose, so the table names that place. Devices that share a Space share its sign-in and saves and take turns streaming it; give simultaneous players separate Spaces and separate accounts.
• To take a device out of a Space, untick it in that Space’s column. If the Space was its Default Space, the device opens the next place it may play. A device that can no longer launch games shows Remove from Spaces in its row instead.
• A device needs permission to launch apps; temporary guests cannot be assigned a Space. When two paired devices share a name, for example Nova and Nova Debug on one handheld, the Spaces and Devices pages add when each one paired. Rename one in Devices to tell them apart for good.

Spaces do not change Steam’s account and library sharing rules.

Play in a Space

1. Open the host in Nova. Playing in in the library toolbar names your Space; Change Space lists the others this device may use. With one permitted Space the library opens straight into it, and the host remembers each device’s last choice.
2. Select the launcher’s own tile, first in the library: Steam Big Picture, Heroic or Lutris. Sign in and install a game there. A Space’s name is a label, not proof of which account is signed in; check or switch the account inside the launcher.
3. Return to the library and refresh it; a newly installed title can take up to 15 seconds to appear. Choose a game and press Play. Start at 60 FPS, check picture, sound and both sticks, then raise the target.

Each Space shows a status: ready, starting, playing (yours), in use (another device), stopping, or unavailable when the host cannot offer it. A Space that reads ready but cannot open because the host is at its limit says so before you press, and a refused launch tells you what to change.

Save before you leave. In this preview, disconnecting ends the Space’s running game. Leave Space asks you to confirm and keeps saves, installed games and the launcher’s sign-in; a dropped connection ends the session the same way. Resume is offered only for a session this device owns and does not promise a disconnected game kept running. Other Spaces keep running.

Nova’s Play Setup saves resolution and frame rate on the device for the next Space launch. Nova offers up to 240 FPS where the display supports it; a selected rate is a target the host must sustain with every intended Space running, so start at 60 and raise it. Switching a streaming preset never switches accounts or Spaces.

Heroic and Lutris

Follow Heroic in a Space or Lutris in a Space for creation, sign-in, installing games and finding them in Nova.

A Heroic Space reads the games installed through Heroic’s Epic, GOG and Amazon backends, and a Lutris Space reads the Lutris library. Both show in Nova’s library behind the launcher’s own tile, a title starts from Nova like a Steam one, and it runs on Proton or Wine inside the Space.

• Sign in inside the launcher. Heroic keeps its own Epic, GOG and Amazon sign-ins and Lutris its own accounts, separate from every other Space.
• A controller reaches the games. Heroic’s own menus do not see a controller yet, so use touch or a mouse in them until the game starts.
• Heroic starts with its update check off. A Space gets a newer Heroic by moving to a newer runtime from its card, not through a package manager it does not have.
• A launcher window fills the stream, and a title started from the launcher shows on the stream in front of it.

Rename, remove and restore

Rename on a Space card changes its name without touching its account or files; refresh the library in Nova afterwards.

Remove Space asks what happens to the Space’s games and saves. Other Spaces stay available either way.

• Archive is already selected. Devices lose access, and installed games, saves, settings and the launcher’s sign-in stay on the host, so archiving frees no disk space. Restore under Archived Spaces brings the Space back without its device access; assign devices again.
• Remove for good deletes the Space with its installed games, saves, settings and sign-in, and frees their disk space. Type the Space’s name exactly as it is shown to confirm. It cannot be undone or restored. An archived Space offers Remove for good beside Restore.

Like every change to Spaces, removing for good needs every Space stream to end first. Polaris deletes only the storage it made for that Space, and only through Docker: if the storage is not the one Polaris created, or Docker does not answer, nothing is removed and the page says why. If Docker stops partway, the Space stays under Archived Spaces, the page names the Docker volume that may still hold its games and saves, and Remove for good again finishes the job. The last Space can be archived but not removed for good, because Polaris makes a new Space from an existing one; create another Space first.

Runtime updates

A Space keeps the gaming runtime it was created with until you move it. When this Polaris build offers a newer compatible runtime for the same launcher, the Space card shows A Newer Gaming Runtime and Move To The Newer Runtime.

1. Save your games and end every Space stream.
2. Select Move To The Newer Runtime on the Space’s card, review what it keeps and confirm Move Space.
3. Wait for the download and move to finish. An uncached runtime is several gigabytes; you can leave the page and return to its progress.
4. Open the Space again. Its name, device access, sign-ins, installed games and saves remain in place.

Move one Space at a time. Polaris refuses a move while a Space stream or another setup/change job is active, or when the runtime does not match the Space’s launcher and player data. Read a reported failure before retrying; recreating the Space is not required to update its runtime.

The button only appears when this Polaris build offers a suitable newer runtime. Updating the launcher inside the container is not the update path. A move after an NVIDIA driver change may use different button text, described under After an NVIDIA driver update.

NVIDIA driver files

The gaming runtime for NVIDIA graphics borrows this PC’s own driver files instead of carrying a copy. That is why a driver update no longer strands a Space: the same runtime keeps working, because it uses whatever driver the kernel has loaded.

Polaris reads those files and passes them to a Space read only, and it checks each one first: owned by root, in the directory the driver package puts it in, and built for the architecture it claims. No driver library is copied, changed or run.

Three small description files are the exception. They tell OpenGL and Vulkan which driver to load, and this PC’s copies name library paths that do not exist inside a Space, so Polaris writes its own corrected copies under spaces-graphics in its configuration directory and passes those instead. On a system with SELinux it also labels those copies for containers, the way Docker labels a shared volume, because a file written in a configuration directory is one no container may read. Without that label a Space starts, finds no NVIDIA driver to load, and falls back to software rendering.

Host Setup shows NVIDIA driver files while an NVIDIA driver is loaded. The one case worth acting on is the 32 bit half, which most distributions package separately:

Distribution	Package
Fedora, Bazzite	xorg-x11-drv-nvidia-libs.i686
Arch, CachyOS	lib32-nvidia-utils
Ubuntu	the libnvidia-gl package for your driver branch, i386 variant

Without it a Space still starts, and 32 bit games, which is most games under Proton, render nothing. Polaris does not install driver packages.

A gaming runtime still names the oldest driver it works with, because its own video encoder is built against a fixed NVIDIA interface. On a driver older than that, Host Setup says to update the driver.

After an NVIDIA driver update

Older NVIDIA runtimes carry the NVIDIA userspace for one driver version, and a Space keeps the runtime it was made with. After the host moves to another NVIDIA driver, such a runtime no longer matches the kernel module, so Polaris refuses to start the Space before anything runs. Nova shows why and says to move the Space; the refusal’s code is space_runtime_driver_mismatch. A Space on a runtime that borrows this PC’s driver never sees this.

The Space card says why, for example Made for NVIDIA driver 610.57.04. This PC runs 615.71.09., and offers Move To The Runtime For Driver 615.71.09 when this Polaris build has a runtime for the new driver. Moving points the Space at that runtime and changes nothing else: its launcher’s sign-in, installed games and saves, name, devices and Default Space stay. The Steam home is not prepared again; both runtimes run as the same account and use it as it is.

1. End every Space stream.
2. Select Move To The Runtime For Driver on the Space’s card and confirm.
3. If the runtime is not on this PC yet, Polaris downloads it first. The download is several gigabytes, and you can leave the page while it runs.
4. Move each other Space that shows the same notice, one at a time.

A move is refused, in words, while the Space or any Space stream is open, while another change to Spaces or Host Setup is running, when the runtime cannot be verified, or when the new runtime needs a different kind of home. Nothing changes when a move is refused or stops partway; move it again. When this build has no runtime for the new driver, the card says so: update Polaris, or go back to the driver the Space was made for. First Space setup keeps its own record of the runtime it started with, and a move does not change it.

Check sound and stuttering

If sound crackles or drops, note the time, the Space, the game, the frame rate, the bitrate and whether the device is on Wi-Fi or Ethernet, and whether picture or controls paused too. Compare the same game over Ethernet or another access point, with downloads and builds paused on the host, changing one thing at a time, and compare one Space with the intended number of players. Low latency and zero reported packet loss do not rule out brief audio pauses; the preview has recorded both host scheduling stalls and wireless delays. Keep the notes for Doctor & Support.

When something goes wrong

• A refused launch in Nova names the reason and the fix: the Space is in use on another device, this device already has a Space running, every Space slot or the encoder is taken, no Space is assigned or selected, the assignment changed, or the Space’s runtime was made for another NVIDIA driver (see After an NVIDIA driver update). Do what it says, then try again.
• A failing host check links its section above. Doctor & Support covers controller and graphics access with the host’s own evidence.
• If a Space stops on its own or loses sound, keep the time and the Space name for diagnosis. A passing setup check does not prove that 120 FPS, every game or every GPU is reliable.
• Keep SELinux enabled, and do not add privileged container flags or mount the whole device tree.

Preview limits

One Space at a time, handheld audio still under investigation, NVIDIA exercised and AMD not yet, Heroic’s own menus without a controller, Docker on system images not automated. The measured results and the exact boundaries are in the preview status report, which links the acceptance and audio reports it summarises.