This is different from using an `APIRouter` as a mounted application is completely independent. The OpenAPI and docs from your main application won't include anything from the mounted application, etc.

You can read more about this in the [Advanced User Guide](../advanced/index.md){.internal-link target=_blank}.

## Details

This sub-application is just another standard FastAPI application, but this is the one that will be "mounted":

```Python hl_lines="11  14-16"
{!../../docs_src/sub_applications/tutorial001.py!}
```

### Mount the sub-application

In your top-level application, `app`, mount the sub-application, `subapi`.

In this case, it will be mounted at the path `/subapi`:

```Python hl_lines="11  19"

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package disk

import "runtime"

// IsRootDisk returns if diskPath belongs to root-disk, i.e the disk mounted at "/"
func IsRootDisk(diskPath string, rootDisk string) (bool, error) {
	if runtime.GOOS == "windows" {
		// On windows this function is not implemented.
		return false, nil
	}
	return SameDisk(diskPath, rootDisk)

	"unsafe"
)

// GetVolumeInformation provides windows drive volume information.
var GetVolumeInformation = kernel32.NewProc("GetVolumeInformationW")

// getFSType returns the filesystem type of the underlying mounted filesystem
func getFSType(path string) string {
	volumeNameSize, nFileSystemNameSize := uint32(260), uint32(260)
	var lpVolumeSerialNumber uint32
	var lpFileSystemFlags, lpMaximumComponentLength uint32

// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package disk

// getFSType returns the filesystem type of the underlying mounted filesystem
func getFSType(fstype []int8) string {
	b := make([]byte, len(fstype))
	for i, v := range fstype {
		b[i] = byte(v)
	}
	return string(b)

	"ef53":     "EXT4",
	"f15f":     "ecryptfs",
	"794c7630": "overlayfs",
	"2fc12fc1": "zfs",
	"ff534d42": "cifs",
	"53464846": "wslfs",
}

// getFSType returns the filesystem type of the underlying mounted filesystem
func getFSType(ftype uint32) string {
	fsTypeHex := strconv.FormatUint(uint64(ftype), 16)
	fsTypeString, ok := fsType2StringMap[fsTypeHex]
	if !ok {
		return "UNKNOWN"
	}
	return fsTypeString
}

	"ef53":     "EXT4",
	"f15f":     "ecryptfs",
	"794c7630": "overlayfs",
	"2fc12fc1": "zfs",
	"ff534d42": "cifs",
	"53464846": "wslfs",
}

// getFSType returns the filesystem type of the underlying mounted filesystem
func getFSType(ftype int64) string {
	fsTypeHex := strconv.FormatInt(ftype, 16)
	fsTypeString, ok := fsType2StringMap[fsTypeHex]
	if !ok {
		return "UNKNOWN"
	}
	return fsTypeString

```html
<a href="/items/42">
```

## Templates and static files

You can also use `url_for()` inside of the template, and use it, for example, with the `StaticFiles` you mounted with the `name="static"`.

```jinja hl_lines="4"
{!../../docs_src/templates/templates/item.html!}
```

In this example, it would link to a CSS file at `static/styles.css` with:

```CSS hl_lines="4"

	"ef53":     "EXT4",
	"f15f":     "ecryptfs",
	"794c7630": "overlayfs",
	"2fc12fc1": "zfs",
	"ff534d42": "cifs",
	"53464846": "wslfs",
}

// getFSType returns the filesystem type of the underlying mounted filesystem
func getFSType(ftype int32) string {
	fsTypeHex := strconv.FormatInt(int64(ftype), 16)
	fsTypeString, ok := fsType2StringMap[fsTypeHex]
	if !ok {
		return "UNKNOWN"
	}
	return fsTypeString
}

- MinIO distributed mode requires **fresh directories**. If required, the drives can be shared with other applications. You can do this by using a sub-directory exclusive to MinIO. For example, if you have mounted your volume under `/export`, pass `/export/data` as arguments to MinIO server.
- The IP addresses and drive paths below are for demonstration purposes only, you need to replace these with the actual IP addresses and drive paths/folders.