Enterprise

# Configure a standalone Driver

> Set the connection, task, and integration parameters of a standalone Driver with its state file, a configuration file, environment variables, or flags.

A standalone Driver reads its parameters from five sources. A source higher in the list overrides the sources below it:

1. Command line flags. See the [CLI reference](https://docs.synnaxlabs.com/reference/enterprise/driver/cli-reference).
2. [Environment variables](https://docs.synnaxlabs.com/reference/enterprise/driver/configuration#environment-variables).
3. A [configuration file](https://docs.synnaxlabs.com/reference/enterprise/driver/configuration#configuration-file).
4. The [state file](https://docs.synnaxlabs.com/reference/enterprise/driver/configuration#state-file), which `synnax-driver login` writes.
5. The defaults.

The parameter flags and the configuration file apply only to `synnax-driver start --standalone`. The Linux and NI Linux Real-Time service always starts with the same command. To configure the service, use `login` and the [environment file](https://docs.synnaxlabs.com/reference/enterprise/driver/configuration#environment-file). Run `login` once, also when the environment file holds the connection: `login` creates the folder of the state file, and the service cannot.

## State file

The state file holds the connection parameters that `login` saves, and the rack key: the key that the Core knows this Driver by.

| Operating system   | Path                                                               |
| ------------------ | ------------------------------------------------------------------ |
| Linux, NI Linux RT | `/var/lib/synnax-driver/persisted-state.json`                      |
| Windows            | `%LOCALAPPDATA%\synnax-driver\persisted-state.json`                |
| macOS              | `~/Library/Application Support/synnax-driver/persisted-state.json` |

The `--state-file` flag of `start --standalone`, `login`, and `clear` sets a different path. The service always uses the default path.

> The state file holds the password as plain text, and each user of the computer can read and change the file. Give the Driver a user with only the [Host role](https://docs.synnaxlabs.com/reference/enterprise/users#roles).

To remove the saved login and the rack key, run `synnax-driver clear`. On the next start, the Driver shows in the devices toolbar as a new Driver. The old entry stays on the Core.

## Environment variables

The Driver reads each parameter from a variable named `SYNNAX_DRIVER_` and the key in upper case. The integrations have no variable.

```bash
SYNNAX_DRIVER_HOST=10.0.0.45
SYNNAX_DRIVER_PORT=9090
SYNNAX_DRIVER_USERNAME=driver
SYNNAX_DRIVER_PASSWORD=password
SYNNAX_DRIVER_SECURE=false
SYNNAX_DRIVER_CORRECT_SKEW=true
SYNNAX_DRIVER_OP_TIMEOUT=60
SYNNAX_DRIVER_POLL_INTERVAL=1
SYNNAX_DRIVER_SHUTDOWN_TIMEOUT=30
SYNNAX_DRIVER_WORKER_COUNT=4
```

To learn what each parameter does, see [Parameters](https://docs.synnaxlabs.com/reference/enterprise/driver/configuration#parameters).

### Environment file

On Linux and NI Linux Real-Time, the service and `login` read `/etc/synnax/driver.env`. Write one `KEY=value` on each line, with no `export`. `login` uses the file only for variables such as `GRPC_DEFAULT_SSL_ROOTS_FILE_PATH`. It does not read the `SYNNAX_DRIVER_` variables.

`install` creates the file. Only root can read it, so edit it and run `login` as root: with `sudo` on Linux, and as `admin` on NI Linux Real-Time. Restart the service after you edit the file.

`start --standalone` does not read the file. For a Driver in a terminal, export the variables in the shell:

```bash
export SYNNAX_DRIVER_WORKER_COUNT=8
synnax-driver start --standalone
```

## Configuration file

Give a JSON file to `start --standalone` with the `--config` flag. Each key is optional. The file cannot hold comments.

```json
{
  "connection": {
    "host": "10.0.0.45",
    "port": 9090,
    "username": "driver",
    "password": "password",
    "secure": false
  },
  "timing": {
    "correct_skew": true
  },
  "manager": {
    "op_timeout": 60,
    "poll_interval": 1,
    "shutdown_timeout": 30,
    "worker_count": 4
  },
  "integrations": ["arc", "ethercat", "http", "labjack", "modbus", "ni", "opc"]
}
```

The `integrations` list replaces the default list. Leave out `remote_info`, so that the Driver registers with the Core on the first start and saves its rack key in the state file.

## Parameters

* [`host`](https://docs.synnaxlabs.com/reference/enterprise/driver/configuration#host)`= localhost`

  The host of the Core.

* [`port`](https://docs.synnaxlabs.com/reference/enterprise/driver/configuration#port)`= 9090`

  The port of the Core.

* [`username`](https://docs.synnaxlabs.com/reference/enterprise/driver/configuration#username)`= synnax`

  The username of the Driver user.

* [`password`](https://docs.synnaxlabs.com/reference/enterprise/driver/configuration#password)`= seldon`

  The password of the Driver user.

* [`secure`](https://docs.synnaxlabs.com/reference/enterprise/driver/configuration#secure)`= false`

  Connect to the Core over TLS.

* [`correct_skew`](https://docs.synnaxlabs.com/reference/enterprise/driver/configuration#correct_skew)`= true`

  Keep the timestamps of hardware-timed NI and LabJack reads in step with the clock of the computer.

* [`op_timeout`](https://docs.synnaxlabs.com/reference/enterprise/driver/configuration#op_timeout)`= 60`

  The number of seconds after which a task operation that has not finished, such as a start, gives the task the error `operation timed out`.

* [`poll_interval`](https://docs.synnaxlabs.com/reference/enterprise/driver/configuration#poll_interval)`= 1`

  The number of seconds between two checks for task operations that have not finished.

* [`shutdown_timeout`](https://docs.synnaxlabs.com/reference/enterprise/driver/configuration#shutdown_timeout)`= 30`

  The number of seconds that the Driver waits for task operations when it stops.

* [`worker_count`](https://docs.synnaxlabs.com/reference/enterprise/driver/configuration#worker_count)`= 4`

  The number of threads that run task operations. Use a value from 1 to 64.

* [`rack_key`](https://docs.synnaxlabs.com/reference/enterprise/driver/configuration#rack_key)`= 0`

  The key that the Core knows this Driver by. With 0, or when the Core has no such key, the Driver registers as a new Driver named after the host name of the computer.

* [`cluster_key`](https://docs.synnaxlabs.com/reference/enterprise/driver/configuration#cluster_key)`= nil UUID`

  The key of the Core that owns `rack_key`. When it is not the key of the Core, the Driver ignores `rack_key` and registers as a new Driver, so set both keys.

* [`integrations`](https://docs.synnaxlabs.com/reference/enterprise/driver/configuration#integrations)`= all`

  The device integrations to run: `arc`, `ethercat`, `http`, `labjack`, `modbus`, `ni`, and `opc`. NI Linux RT has no `modbus`.

For a boolean environment variable, use `true` or `false`.