Environment variables

Deployment and process settings are supplied through environment variables in deploy/.env. Instance settings and many host settings are persisted and editable through the admin UI; where both exist, the table notes whether the environment is a seed, fallback, or authoritative override.

Many node agent settings can also be overridden per host from Admin, Fleet, Hosts, Settings, which is usually easier than editing a file on every machine. Precedence runs: per-host override, then agent environment, then catalog default.

Required

Variable	Notes
`DATABASE_URL`	Postgres connection string.
`ENROLLMENT_TOKEN`	Shared secret agents present on first contact. Must match on control plane and every agent.
`CONTROL_PLANE_URL`	Agent side. WebSocket URL of the control plane.
`POSTGRES_PASSWORD`	Compose. Generated on a fresh install.

The release install has you generate these values before first boot. The source-build redeploy.sh path generates missing secrets and never overwrites existing ones.

Setup and identity

Variable	Default	Purpose
`BOOTSTRAP_ADMIN_EMAIL`	unset	Provisions the first admin at boot. Idempotent.
`BOOTSTRAP_ADMIN_USERNAME`	unset	With the above.
`BOOTSTRAP_ADMIN_PASSWORD`	unset	With the above. Set all three or none.
`REGISTRATION_MODE`	`closed`	Seeds the registration mode on first boot of a fresh database only. The admin UI is authoritative afterwards.
`PUBLIC_BASE_URL`	unset	Canonical public URL for invite links and proxied signaling. Set it when a proxy rewrites `Host`; otherwise the public host can be derived from forwarded or request headers.
`NODE_NAME`	hostname	Agent side. A stable identity for this host.

Secrets

Variable	Default	Purpose
`QUASAR_SECRET_KEY`	unset	Base64 of 32 bytes. Encrypts credentials stored through the admin UI. Back this up. It is not recoverable.

TLS and access

Variable	Default	Purpose
`QUASAR_TLS`	`auto`	`auto` or `off`.
`QUASAR_TLS_ADDR`	`:8443`	HTTPS listener.
`QUASAR_TLS_HOSTS`	unset	Comma-separated names and IPs the generated certificate should cover. Required for LAN access.
`QUASAR_TLS_CERT`	unset	Your own certificate. Set with the key or not at all.
`QUASAR_TLS_KEY`	unset	Your own key.
`QUASAR_TLS_DIR`	`/var/lib/quasar-control/tls`	Where the generated certificate is kept.
`QUASAR_HTTP_REDIRECT`	`auto`	HTTP to HTTPS redirect for browser routes.
`QUASAR_ALLOWED_ORIGINS`	unset	Authoritative override for signaling WebSocket origins. Leave unset to manage them in Admin, Settings; with neither source set, same-origin is allowed. `*` is rejected.
`QUASAR_TRUSTED_PROXIES`	unset	Proxy IPs or CIDRs whose forwarded client-address headers are trusted. Empty ignores forwarded addresses.
`LISTEN_ADDR`	`:8080`	HTTP listener.
`CONTROL_PORT`	`8080`	Compose. Host port for HTTP.
`QUASAR_TLS_PORT`	`8443`	Compose. Host port for HTTPS.

Storage

Variable	Default	Purpose
`QUASAR_HOME_ROOT`	unset	Lowest-priority managed-home root fallback. A host with no effective root cannot launch a managed-home app. Fresh `redeploy.sh` installs seed `/var/lib/quasar/homes`.
`QUASAR_STORAGE_PROVIDER`	`auto`	`auto` or `local`, which both select mount-path storage. `volume` was removed and is rejected.
`QUASAR_ARTWORK_DIR`	`/var/lib/quasar-control/artwork`	Artwork cache. Needs a persistent volume.
`QUASAR_ARTWORK_PROVIDER`	`steamgriddb`	`steamgriddb` or `none`.
`QUASAR_STEAMGRIDDB_API_KEY`	unset	Or set it through the admin UI, which takes precedence.

Encoding

Variable	Default	Purpose
`QUASAR_ENCODER`	unset, auto-detect	AMD and NVIDIA default to `vulkan`, Intel to `va`, and no GPU to `openh264`. Explicit `va`, `nvenc`, `vulkan`, or `openh264` wins.
`QUASAR_RENDER_NODE`	unset	Optional DRM render-node pin. Prefer a `/dev/dri/by-path/` path when pinning a multi-GPU host.
`QUASAR_CUDA_DEVICE`	`0`	NVENC device index on a multi-GPU host.
`QUASAR_ZEROCOPY`	off	Full zero-copy on the VA path.
`QUASAR_GOP`	`60`	Frames between keyframes.
`QUASAR_SLICES`	`8`	H.264 slices per frame. Supported by Quasar’s patched Vulkan H.264 encoder as well as applicable vendor paths.
`QUASAR_TARGET_USAGE`	`6`	VA speed against quality, 1 to 7.
`QUASAR_QUEUE_BUFFERS`	`3`	Encode queue depth.
`QUASAR_VULKAN_H264`	on	Set `0` to move H.264 off Vulkan when a vendor fallback exists.
`QUASAR_VULKAN_HEVC`	on	Set `0` to move HEVC off Vulkan when a vendor fallback exists.
`QUASAR_VULKAN_AV1`	on	Set `0` to move AV1 off Vulkan when a vendor fallback exists.
`QUASAR_VULKAN_MAX_SESSIONS`	`2`	Concurrent Vulkan encode sessions per GPU.
`QUASAR_REQUIRE_HW_RENDER`	`1`	Fail a session that falls back to software rendering.

Adaptive bitrate

Variable	Default	Purpose
`QUASAR_ABR_MODE`	`smooth`	`smooth`, `protective` or `off`.
`QUASAR_ABR`	`1`	Legacy on and off. `0` maps to `off`.
`QUASAR_ABR_FLOOR_KBPS`	unset	Explicit floor.
`QUASAR_ABR_FLOOR_RATIO`	`0.3`	Floor as a fraction of the tier bitrate.
`QUASAR_ABR_LADDER`	on in `smooth`	Encoder speed escalation under saturation.
`QUASAR_ABR_LADDER_RESOLUTION`	off	Opt-in external-resolution rung. Requires `smooth`; applies to the next session.
`QUASAR_ABR_LADDER_FPS`	off	Opt-in 120-to-60 FPS rung. Requires `smooth`; applies to the next session.

Roughly fifteen further hysteresis settings exist. Every default matches the value that used to be hardcoded. Do not change them without a measurement.

Capacity and placement

Variable	Default	Purpose
`QUASAR_VRAM_MIN_FREE_MB`	`1024`	Free GPU memory floor for admission. `0` disables the veto.
`QUASAR_VRAM_INFLIGHT_ESTIMATE_MB`	the floor	Memory debited for very recent launches.
`QUASAR_VRAM_STALENESS_SECS`	`20`	How fresh a memory sample has to be.
`QUASAR_PLACEMENT_POLICY`	`spread`	`spread`, `least-loaded` or `locality`.

Apps and containers

Variable	Default	Purpose
`QUASAR_APP_DISPLAY_ENV`	on	Inject session resolution and frame rate into app containers.
`QUASAR_APP_GAMESCOPE_ENV`	on	Also emit the gamescope compatibility variables.
`QUASAR_APP_SHM_SIZE`	`1g`	Shared memory for app containers.
`QUASAR_APP_STOP_TIMEOUT_SECS`	`10`	Graceful stop window.
`QUASAR_APP_PUID`	unset	Run apps as this user ID.
`QUASAR_APP_PGID`	unset	Run apps as this group ID.
`QUASAR_APP_PIDS_LIMIT`	`8192`	Process limit backstop.
`QUASAR_IDLE_TIMEOUT_SECS`	`120`	Reap idle sessions after this long.

Audio and microphone

Variable	Default	Purpose
`QUASAR_AUDIO_REQUIRED`	off	Fail the session rather than run silently. Worth setting.
`QUASAR_MIC_DISABLED`	off	Host-level microphone kill switch.

Libraries and images

Variable	Default	Purpose
`QUASAR_LIBRARY_SCAN_INTERVAL`	360 minutes	Library discovery interval. `0` disables scheduled scans.
`QUASAR_LIBRARY_PROVIDERS`	`steam`	Allowlisted providers.
`QUASAR_IMAGE_REGISTRY_HOSTS`	`ghcr.io`	Registries Quasar will resolve digests and artwork from.
`QUASAR_ARTWORK_MAX_BYTES`	`8388608`	Cap on fetched artwork, 8 MiB.

Experimental

Variable	Default	Purpose
`QUASAR_FEC_MODE`	derived	`off`, `fixed` or `auto`. Not recommended for browsers.
`QUASAR_FEC_PERCENTAGE`	`0`	Redundancy percentage.
`QUASAR_INTRA_REFRESH`	`0`	Vulkan only, patched image only.
`QUASAR_INTRA_REFRESH_PERIOD`	`0`	`60` is the validated value.

See Experimental options before enabling any of these.

The host sysctl

Not an environment variable, but required on every host that serves media:

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