Comment 26 for bug 1890803

overlayroot should generate correct and valid /etc/fstab for the rootfs it will mount.
i.e. the
/media/root-ro/ / overlay lowerdir=/media/root-ro/,upperdir=/media/root-rw/overlay/,workdir=/media/root-rw/overlay-workdir/_ 0 0

However, it needs not to take any /etc/fstab as input to generate that. Currently the code requires for /media/root-ro/etc/fstab to exist, and contain '/' entry which will get replaced by above.

Surely the right thing to do here is for overlayroot module to write out the /media/root-ro/ etc without needing a mock 'fstab' without the false entry `LABEL=cloudimg-rootfs /media/root-ro/ ext4 ro,defaults,noauto 0 0`.