Spaces

A Space is a separate Steam sign-in, game library and set of saves on one Linux gaming PC. 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. Two limits shape everything below: the host runs one Space at a time, and the gaming runtime is not published for download yet, so the catalog in Host Setup stays empty until it is.

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	Steam and the software that runs inside each Space, downloaded by Docker from GitHub Container Registry
Nova on your device	Opens the stream and sends your controls

Steam, its 32-bit libraries and the gaming userspace live inside the runtime image, so the host does not need Steam installed. The host still needs Polaris, Docker, its GPU driver and input permissions. An NVIDIA image names the host driver version it was built for; the current preview image targets NVIDIA 610.57.04.

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 seven 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.

Prepare Docker from Spaces

1. If Docker Engine needs attention, install it with your distribution’s steps below, in a terminal on the Polaris host.
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 and stop streams before signing out and back in. If Polaris runs as a system service, restart that service so it picks up 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:

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

2. Finish your games, stop Space streams and quit Polaris. If it runs as a service, stop the service first.
3. Run the helper from the native package:

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

4. 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, or an input rule with no ownership record, are reported for review rather than replaced.

If the helper refuses, its message names the situation:

• “An existing Spaces policy is disabled, overridden or locally managed.” A module with one of the helper’s names is installed at another priority, for example a copy installed by hand. sudo semodule -lfull | grep polaris shows it with its priority. Remove that copy, for example sudo semodule -X 400 -r polaris_multiseat_input polaris_nvidia_worker, then run the install again. libsemanage may print “Failed!” while removing; trust the list, not the message.
• “Quit Polaris and stop Spaces streams before changing security setup.” A process named polaris or polaris-something is still running, a second instance included. pgrep -a polaris names it; stop it and retry.
• “Existing Spaces input rule is not owned by this setup.” /etc/udev/rules.d/97-polaris-multiseat-input.rules was placed there by hand, so the helper has no record of it. Move it aside and run the install again; the helper writes and records its own copy.

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.

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 NVIDIA variant names the host driver it needs.
2. Select Download and prepare. 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 Default Space, assign your paired Nova device to the new Space.

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 Steam 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 and give it a recognisable name, a player or a room.
3. If asked, choose an existing Steam setup. The new Space reuses its runtime configuration and gets its own storage and no copied sign-in.
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

• Default Space on the Spaces page lists the handhelds, TVs and computers paired with Polaris. Choose the Space each device opens first and select Save assignment. Devices assigned to the same Space share its sign-in and saves and take turns streaming it; give simultaneous players separate Spaces and separate Steam accounts.
• Device Access on a Space card allows more devices into that Space. A device with more than one permitted Space picks between them in Nova with Change Space.
• Desktop is this PC’s usual desktop and apps. Under Default Space it clears all of a device’s Space access; under Desktop Access it becomes one more choice beside the device’s Spaces.
• A device needs permission to launch apps; temporary guests cannot be assigned a Space. Rename an unfamiliar device in Devices.

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 Steam Big Picture, sign in and install a game. A Space’s name is a label, not proof of which Steam account is signed in; check or switch the account inside Steam.
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 Steam 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.

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 archives it after a confirmation: devices lose access, other Spaces stay available, and installed games, saves, settings and the sign-in stay on the host. It frees no disk space and deletes no Docker volume. Restore under Archived Spaces brings it back without its device access; assign devices again.

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, or the assignment changed. 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, no runtime download until an image is published, handheld audio still under investigation, NVIDIA exercised and AMD not yet, 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.