nixpkgs/nixos/tests/activation/etc-overlay-mutable.nix
nikstur 6abbe725ca nixos/etc: handle mountpoints on top of /etc when switching
The activation script that remounts the /etc overlay now handles other
mount points on top of /etc by bind mounting them to the new temporary
/etc overlay and then atomically revealing it.
2024-07-18 21:28:53 +02:00

49 lines
1.6 KiB
Nix

{ lib, ... }: {
name = "activation-etc-overlay-mutable";
meta.maintainers = with lib.maintainers; [ nikstur ];
nodes.machine = { pkgs, ... }: {
system.etc.overlay.enable = true;
system.etc.overlay.mutable = true;
# Prerequisites
boot.initrd.systemd.enable = true;
boot.kernelPackages = pkgs.linuxPackages_latest;
specialisation.new-generation.configuration = {
environment.etc."newgen".text = "newgen";
};
};
testScript = ''
with subtest("/etc is mounted as an overlay"):
machine.succeed("findmnt --kernel --type overlay /etc")
with subtest("switching to the same generation"):
machine.succeed("/run/current-system/bin/switch-to-configuration test")
with subtest("switching to a new generation"):
machine.fail("stat /etc/newgen")
machine.succeed("echo -n 'mutable' > /etc/mutable")
# Directory
machine.succeed("mkdir /etc/mountpoint")
machine.succeed("mount -t tmpfs tmpfs /etc/mountpoint")
machine.succeed("touch /etc/mountpoint/extra-file")
# File
machine.succeed("touch /etc/filemount")
machine.succeed("mount --bind /dev/null /etc/filemount")
machine.succeed("/run/current-system/specialisation/new-generation/bin/switch-to-configuration switch")
assert machine.succeed("cat /etc/newgen") == "newgen"
assert machine.succeed("cat /etc/mutable") == "mutable"
print(machine.succeed("findmnt /etc/mountpoint"))
print(machine.succeed("stat /etc/mountpoint/extra-file"))
print(machine.succeed("findmnt /etc/filemount"))
'';
}