> For the complete documentation index, see [llms.txt](https://docs.umh.app/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.umh.app/reference/environment-variables.md).

# Environment Variables

This is the reference for all environment variables used by umh-core. These variables override or supplement configuration from `config.yaml`.

| Name                    | Values                                                                     | Description                                                                                                                                                                                                                                                                                                                                                                                                                                  |
| ----------------------- | -------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| LOGGING\_LEVEL          | ERROR, WARN, INFO, DEBUG                                                   | Controls log verbosity. DEBUG shows detailed internal operations                                                                                                                                                                                                                                                                                                                                                                             |
| AUTH\_TOKEN             | (Base64 encoded token)                                                     | Management Console authentication token. Overrides auth token from config.yaml                                                                                                                                                                                                                                                                                                                                                               |
| API\_URL                | <https://management.umh.app/api>, <https://staging.management.umh.app/api> | Management Console API endpoint. Use staging for testing environments                                                                                                                                                                                                                                                                                                                                                                        |
| RELEASE\_CHANNEL        | enterprise, stable, nightly                                                | Auto-update channel. Enterprise = most stable, nightly = latest features                                                                                                                                                                                                                                                                                                                                                                     |
| S6\_PERSIST\_DIRECTORY  | true/1/TRUE/True, (unset/false/other)                                      | Controls S6 service directory persistence. Truthy values (true, 1, TRUE, etc.) = /data/services (persist across container restarts for debugging). Default/false = /tmp/umh-core-services (cleared on container restart for fresh state)                                                                                                                                                                                                     |
| USE\_CANONICALIZE\_FAST | 0, 1, false, true (default: 1)                                             | Compares a bridge's desired and running configuration by walking the values directly. Set to 0 and restart the container to fall back to the slower YAML round-trip, the reference implementation, if a configuration is ever reported as changed on every tick. The value is read as a boolean, so `1`/`0`, `true`/`false` and `t`/`f` all work in any capitalization; anything else falls back too, and logs a warning naming what was set |
| LOCATION\_<0-6>         | (string values)                                                            | Sets Agent location path levels 0-6. Example: LOCATION\_0=factory, LOCATION\_1=line1                                                                                                                                                                                                                                                                                                                                                         |


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