Docker Volume type "tmpfs"

How can we store container data in memory using docker volume
We use docker tmpfs volume to store container data in host's memory. As we are storing this in memory it will be volatile. Also we can not attach this volume with some other container because we don't know the Physical location in this case.

Example:
docker run -itd --name tmpfstest --tmpfs /var/tmpfs ubuntu

Now if we inspect this container, we will get following in output:
"Tmpfs": {
"/var/tmpfs": ""
}