I would like to mount and unmount USB drives such that their contents can be seen from within a Docker container while it is running. I’ve mapped the directory to the container which the USB drives will be mounted to.
- The docker container cannot see folders/files that are mounted to its volume mapped folder if the container was started before mounting the USB drives.
- If the container is started after the USB is mounted the files can be seen, however, unmounting and mounting again will not show the contents.
Here’s what I’ve tried:
I will be mounting a USB to the directory
/some_folder/usb which is mapped to a docker container.
Start a container with the volume
/some_folder mapped to the same named directory inside it:
$ docker run --name mycontainer -it -v /some_folder:/some_folder ubuntu bash
Detach from the container (CTRL+P+Q), connect a USB drive and mount it to the host directory as root:
$ mount /dev/sda1 /some_folder/usb/
Verify there are files mounted to the host directory:
$ ls -al /some_folder/usb/ drwxr-xr-x 10 root root 8192 Jan 1 1970 . drwxr-xr-x 3 root root 1024 Mar 13 16:44 .. drwxr-xr-x 5 root root 8192 Jul 20 2018 files
Enter the container and check the mapped directory:
$ docker exec -it mycontainer bash root@mycontainer# ls -al /some_folder/usb
Contents of mounted folder is empty inside container.