700 B
700 B
Overlayfs
NixOS offers a convenient abstraction to create both read-only as well writable overlays.
fileSystems = {
"/writable-overlay" = {
overlay = {
lowerdir = [ writableOverlayLowerdir ];
upperdir = "/.rw-writable-overlay/upper";
workdir = "/.rw-writable-overlay/work";
};
# Mount the writable overlay in the initrd.
neededForBoot = true;
};
"/readonly-overlay".overlay.lowerdir = [
writableOverlayLowerdir
writableOverlayLowerdir2
];
};
If upperdir
and workdir
are not null, they will be created before the
overlay is mounted.
To mount an overlay as read-only, you need to provide at least two lowerdir
s.