may need to use a privileged container or configure the mount outside of
Docker.

> [!CAUTION]
> Running containers with `--privileged` grants elevated permissions and can
> expose the host system to security risks. Use this option only when
> absolutely necessary and in trusted environments.

```console
$ docker run --privileged -it debian sh
/# mount -t tmpfs -o <options> tmpfs /data
```

### Options for --mount

The `--mount` flag consists of multiple key-value pairs, separated by commas
and each consisting of a `<key>=<value>` tuple. The order of the keys isn't
significant.

```console
$ docker run --mount type=tmpfs,dst=<mount-path>[,<key>=<value>...]
```

Valid options for `--mount type=tmpfs` include:

| Option                         | Description                                                                                                            |
| :----------------------------- | :--------------------------------------------------------------------------------------------------------------------- |
| `destination`, `dst`, `target` | Container path to mount into a tmpfs.                                                                                  |
| `tmpfs-size`                   | Size of the tmpfs mount in bytes. If unset, the default maximum size of a tmpfs volume is 50% of the host's total RAM. |
| `tmpfs-mode`                   | File mode of the tmpfs in octal. For instance, `700` or `0770`. Defaults to `1777` or world-writable.                  |

```console {title="Example"}
$ docker run --mount type=tmpfs,dst=/app,tmpfs-size=21474836480,tmpfs-mode=1770
```

## Use a tmpfs mount in a container

To use a `tmpfs` mount in a container, use the `--tmpfs` flag, or use the
`--mount` flag with `type=tmpfs` and `destination` options. There is no
`source` for `tmpfs` mounts. The following example creates a `tmpfs` mount at
`/app` in a Nginx container. The first example uses the `--mount` flag and the
second uses the `--tmpfs` flag.

{{< tabs >}}
{{< tab name="`--mount`" >}}

```console
$ docker run -d \
  -it \
  --name tmptest \
  --mount type=tmpfs,destination=/app \
  nginx:latest
```

Verify that the mount is a `tmpfs` mount by looking in the `Mounts` section of
the `docker inspect` output:

```console
$ docker inspect tmptest --format '{{ json .Mounts }}'
[{"Type":"tmpfs","Source":"","Destination":"/app","Mode":"","RW":true,"Propagation":""}]
```

{{< /tab >}}
{{< tab name="`--tmpfs`" >}}

```console
$ docker run -d \
  -it \
  --name tmptest \
  --tmpfs /app \
  nginx:latest
```

Verify that the mount is a `tmpfs` mount by looking in the `Mounts` section of
the `docker inspect` output:

```console
$ docker inspect tmptest --format '{{ json .Mounts }}'
{"/app":""}
```

{{< /tab >}}
{{< /tabs >}}

Stop and remove the container:

```console
$ docker stop tmptest
$ docker rm tmptest
```

## Next steps

- Learn about [volumes](volumes.md)
- Learn about [bind mounts](bind-mounts.md)
- Learn about [storage drivers](/engine/storage/drivers/)