# Version Tracks

Tracks are named lanes for managed versions, such as `dev`, `staging`, and `prod`. A track can override base catalog entries and defaults without duplicating the full catalog.

The active track resolves from a command argument, the `--track` flag, `version.track` in `atmos.yaml`, and then `default`.

## Configuration

**File:** `atmos.yaml`

```yaml
version:
  track: prod

  dependencies:
    nginx:
      ecosystem: oci
      datasource: oci-tags
      provider: dockerhub
      package: library/nginx
      desired: "1.29.0"

  tracks:
    dev:
      defaults:
        update:
          strategy: minor
          cooldown: 0h

    prod:
      defaults:
        update:
          strategy: patch
          cooldown: 14d
      dependencies:
        nginx:
          desired: "1.28.0"
```

## Fields

- **`version.track`**
  Default track name for commands and runtime version resolution.
- **`version.tracks.<name>.extends`**
  Optional parent track to inherit from.
- **`version.tracks.<name>.defaults`**
  Track-level defaults that override 
  `version.defaults`
  .
- **`version.tracks.<name>.dependencies`**
  Track-level dependency overrides merged with the base catalog.

## Examples

```shell
atmos version track list
atmos version track show prod
atmos version track update prod --group=infrastructure
```