I managed to solve it by automatically restarting the container once the drive is mounted, as the mount is done by a systemd service. Guess there were no permission issues

Nevermind, what I ended up doing is restarting the container just after the drive has been mounted. Which is easy because it’s a systemd service so I could use ExecStartPost

Thanks for your answer. I tried mounting it to a folder inside the one I’m using in the compose file but strangely it didn’t work. So I thought that the only way that wouldn’t need to delay docker start is to restart the container just after the drive has been mounted.

And that’s what I ended up doing as the drive mount is a systemd service and therefore I can use ExecStartPost to restart the container. That way this doesn’t affect other containers and also lets this one start even if the drive has not been mounted which I want in case there’s no internet connection

Thanks for your suggestion. That’s what I first thought but there are some issues.

I have other containers that do not require this drive to be mounted. Main problem is that if for some reason the drive cannot be mounted (e.g. no internet connection), then docker would not start any of those containers.

That’s why I need a particular solution. While writing this it has come my mind that I’ve got a container which mounts / as a read-only volume in its /mnt and it seems to work fine there. Maybe if I set the volume to mount /media/user instead of the drive it would work?

Don’t think it has to do with permissions as if I manually start the container after the drive gets mounted then everything goes as expected and the container has the files at /mnt

I mount it using rclone mount as a systemd service, just as they say in their guide

GrapheneOS lets you choose whether you want to have a sandboxed google play installation. This way apps such as Maps work. Basically you are in control (except for Google Pay).

Your comment made me happy