# Configuration

Most installations can keep the defaults. Settings come from environment
variables and an env file:

| How you start Fluksio | Env file |
|---|---|
| `fluksio serve` | `<data-dir>/env`, unless `FLUKSIO_ENV_FILE` names another file |
| Docker with the Makefile | `.env` in this repository's root |

Exported variables override the file. `fluksio serve` flags override both.
For CLI installations, select storage with `--data-dir`, `FLUKSIO_HOME` or
`--global`; see [The fluksio command](../code/cli.md).

## Storage

| Variable | Default | Purpose |
|---|---|---|
| `DATA_DIR` | `flow-data`; CLI uses `./.fluksio` or `~/.fluksio` with `--global` | base directory for instance data |
| `DATABASE_URL` | SQLite at `$DATA_DIR/fluksio.db` | SQLite URL; other database engines are unsupported |
| `FLOWS_DIR` | `$DATA_DIR/flows` | flow git repository |
| `SECRETS_FILE` | `$DATA_DIR/secrets.enc` | encrypted credentials |
| `ALERTS_FILE` | `$DATA_DIR/alerts.json` | alert channels and rules |
| `WEBPUSH_FILE` | `$DATA_DIR/webpush.json` | push keys and browser subscriptions |
| `PROVISIONERS_FILE` | `$DATA_DIR/provisioners.json` | optional worker provisioning configuration |
| `PANELS_FILE` | `$DATA_DIR/panels.json` | wall-panel pairings |
| `OAUTH_PRIVATE_KEY_FILE` | `$DATA_DIR/oauth-key.pem` | agent and worker signing key |
| `CLOUD_CONFIG_FILE` | `$DATA_DIR/cloud.json` | optional portal enrollment |
| `AI_CONFIG_FILE` | `$DATA_DIR/ai.json` | optional assistant provider configuration |
| `CHATS_DIR` | `$DATA_DIR/chats` | assistant transcripts |
| `NODE_VENV` | `auto` | interpreter for node code |

Changing `DATA_DIR` moves the derived paths unless you set them individually.
Docker stores instance data under `/data` on the `app-flow-data` volume.

| `NODE_VENV` value | Behavior |
|---|---|
| `auto` | keeps an existing managed venv; otherwise uses the installation's venv when available, or creates a managed one |
| `managed` | creates a venv under `DATA_DIR`; the Modules screen manages its packages |
| interpreter or venv path | uses the specified Python environment |

Docker uses `managed`. When Fluksio adopts your own venv, the Modules screen
is read-only; install packages into that environment yourself.

Back up the whole data directory and the persistent `SECRET_KEY`. The single
container keeps both, and its Redis, on the `/data` volume. The operator stack
under `docker/` keeps `.env` and `app-flow-data`, plus `app-redis-data` for
live state. Compose prefixes volume names with the project name.
Keep runtime files on persistent storage so rebuilds preserve credentials,
pairings and subscriptions.

## Live state

| Variable | Default | Purpose |
|---|---|---|
| `REDIS_HOST` | unset | unset uses memory, or the image's own Redis in Docker; a Redis host enables persistent flow state |
| `REDIS_PORT` | `6379` | Redis port |

Live state includes message values, node memory and queued work. In-memory
state is lost on restart. The Docker image starts a Redis of its own with
append-only persistence in `/data/redis` whenever `REDIS_HOST` is unset. Set
`REDIS_HOST` to use an external one instead, as the operator stack does with
its `app-redis-data` volume. The default sync policy may lose about a second of
recent writes after a power cut.

## Accounts and access

| Variable | Default | Purpose |
|---|---|---|
| `SECRET_KEY` | generated | signs sessions and encrypts the secrets store; the CLI persists it and `make init` writes it to `.env` |
| `ACCESS_TOKEN_EXPIRE_MINUTES` | `11520` (8 days) | session-token lifetime |
| `FIRST_SUPERUSER` | unset | initial administrator email; the CLI creates an account if needed |
| `FIRST_SUPERUSER_PASSWORD` | unset | initial password; the CLI generates and prints one if needed |
| `FRONTEND_HOST` | `http://localhost:5173`, `http://localhost:8000` in Docker | the address people and devices reach the instance at; panel links, mails and the OAuth issuer use it |
| `BACKEND_CORS_ORIGINS` | `[]` | allowed origins, as comma-separated URLs or a JSON list; `FRONTEND_HOST` is also allowed |
| `FORWARDED_ALLOW_IPS` | `127.0.0.1` | trusted proxies; Docker adds `172.16.0.0/12` |
| `SIGNUP_ENABLED` | `false` | allows account creation from the login page; otherwise use **Admin → Users** |

!!! warning "Keep your secret key"

    Changing `SECRET_KEY` signs everyone out and makes existing encrypted
    secrets unreadable. Back it up with your data.

## Interface address

The image serves the interface and the API on one origin, so the interface
calls the API as a path on whatever address served it. One build works behind
any port, hostname or reverse proxy. `FRONTEND_DIST` points at the built
interface and is set by the image. A checkout leaves it empty and runs the Vite
dev server, which needs its origin in `BACKEND_CORS_ORIGINS`.

## Image options

The `EXTRAS` build argument picks the optional features built into the image,
comma separated. Empty, the default, is the minimal engine.

| Extra | Adds |
|---|---|
| `mqtt` | the MQTT node |
| `influx` | the InfluxDB node |
| `email` | outbound mail, such as password resets |
| `sentry` | error reporting to `SENTRY_DSN` |
| `ml` | numpy, for the `mlp` node |
| `server` | all of the above |

A node whose extra is missing says so on the canvas. The same names work as
pip extras, such as `pip install 'fluksio[mqtt]'`. Connector packages built
with `make connectors` are installed into the image too.

## Environment

| Variable | Default | Purpose |
|---|---|---|
| `ENVIRONMENT` | `local` | `local`, `staging` or `production` |
| `PRIVATE_API_ENABLED` | `false` | test endpoints; also requires `ENVIRONMENT=local` |
| `API_DOCS_ENABLED` | `false` | opens `/docs`, `/redoc` and `/api/v1/openapi.json` to network callers outside production |
| `TZ` | host timezone; Docker defaults to `UTC` | timezone used by cron schedules |

API documentation is available to loopback callers outside production.
`API_DOCS_ENABLED=true` opens it to other callers, as the Docker development
stack does. Production disables it entirely. Staging and production also
refuse `changethis` values for the session key or administrator password.

Set `TZ` in `.env` for schedules that should follow local time, such as
`Europe/Berlin`. `make up`, `make update` and `make dev` warn when `.env` lacks
it, or any other key `.env.example` lists that Compose would otherwise default.

## Engine and resources

| Variable | Default | Purpose |
|---|---|---|
| `FLOW_MAX_WORKERS` | `4` | local node-code subprocesses |
| `FLOW_MAX_CASCADES` | `4` | concurrent live message cascades |
| `FLOW_MAX_RUNS` | `4` | concurrent batch runs |
| `FLOW_NODE_TIMEOUT` | `0` | maximum node silence in seconds, unless the node overrides it; `0` disables |
| `FLOW_CPUS` | `0` | CPU budget; `0` detects cores and reserves two for the engine |
| `FLOW_GPUS` | `0` | local GPU count; `0` counts the engine's `CUDA_VISIBLE_DEVICES`, or NVIDIA device nodes without it |
| `FLOW_RAM` | `0` | memory budget in MB; `0` detects host/container memory and reserves 1 GiB |
| `FLOW_WORKER_MAX_RSS_MB` | `0` | retire a local worker above this memory use after a call; `0` disables |
| `FLOW_NODE_STOP_TIMEOUT` | `5` | seconds a node gets to stop during a rebuild before the rebuild moves on |
| `FLOW_PIPELINE_REBUILD_WAIT` | `15` | seconds a request waits for a running whole-pipeline rebuild before it gets a 503 |
| `FLOW_REBUILD_WAIT` | `5` | the same for a single flow's rebuild, such as a deploy |
| `FLOW_RESTART_BACKOFF` | `[1,5,30,60]` | seconds between restarts of a crashed node loop; the last step repeats |
| `FLOW_CANCEL_GRACE` | `5` | seconds a cancelled node loop gets to stop before it is abandoned |
| `OBS_RETENTION_DAYS` | `30` | retention for metrics, events and run records |

The three concurrency limits must be at least `1`. They also have CLI flags:
`--max-workers`, `--max-cascades` and `--max-runs`. When `FLOW_MAX_WORKERS` or
`FLOW_MAX_CASCADES` is more than four times the machine's core count, the
engine logs a warning at startup and uses the value anyway. Resource flags are
`--gpus`, `--ram` and `--worker-max-rss`.

Nodes with declared resources are scheduled against the available budget.
Undeclared nodes use the shared pool and receive thread caps. Attached workers
report their own inventory; the engine's resource settings describe only its
own machine. See [Remote workers](../code/workers.md) and the **Workers** screen.

When the engine runs with `CUDA_VISIBLE_DEVICES`, a node's card is named the
way that list names it, so under `2,3` the first card is device `2`. UUID and
MIG entries are passed on as written.

## Artifacts

| Variable | Default | Purpose |
|---|---|---|
| `MAX_ARTIFACT_BYTES` | `2147483648` (2 GiB) | upload limit; `0` removes it |
| `ARTIFACT_GC_INTERVAL_S` | `3600` | cleanup interval; `0` disables |
| `ARTIFACT_GC_GRACE_S` | `3600` | minimum age before cleanup |
| `ARTIFACT_VOLATILE_DIR` | auto-detected | live-media directory under `/dev/shm`, or the temporary directory |
| `ARTIFACT_VOLATILE_BYTES` | `50331648` (48 MiB) | live-media ring size; `0` stores volatile saves durably |

Cleanup removes durable artifacts no longer referenced by recorded runs or
current messages, and pauses while a run is active. Volatile artifacts use a
bounded ring; the oldest disappear as it fills. Recorded run outputs are
copied into durable storage. If you increase the ring size in Docker, increase
`shm_size` too.

## Agents

| Variable | Default | Purpose |
|---|---|---|
| `MCP_ENABLED` | `false` | enables `/mcp` and OAuth client registration; `.env.example` sets it to `true` |
| `MCP_TOKEN_EXPIRE_MINUTES` | `60` | access-token lifetime |
| `MCP_REFRESH_EXPIRE_DAYS` | `30` | refresh-token lifetime |
| `OAUTH_CODE_EXPIRE_SECONDS` | `60` | authorization-code lifetime |

See [Agents over MCP](../code/agents.md).

## Mail and monitoring

Password-reset mail requires `SMTP_HOST` and `EMAILS_FROM_EMAIL`.

| Variable | Default |
|---|---|
| `SMTP_HOST` | unset |
| `SMTP_PORT` | `587` |
| `SMTP_USER` / `SMTP_PASSWORD` | unset |
| `SMTP_TLS` / `SMTP_SSL` | `true` / `false` |
| `EMAILS_FROM_EMAIL` | unset |
| `EMAILS_FROM_NAME` | `PROJECT_NAME`, normally `Fluksio` |
| `EMAIL_RESET_TOKEN_EXPIRE_HOURS` | `48` |
| `SENTRY_DSN` | unset; enables error reporting when configured |

`GET /api/v1/utils/health/` checks the event loop and state backend. Docker
uses it as a health check; `make up` also starts the autoheal service to restart
an unhealthy backend.