75 lines
2.2 KiB
Nix
75 lines
2.2 KiB
Nix
{ pkgs, inputs, ... }:
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{
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imports = [
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inputs.impermanence.nixosModules.impermanence
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];
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environment.persistence."/persist" = {
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directories = [
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];
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files = [
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"/etc/machine-id"
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"/etc/ssh/ssh_host_ed25519_key"
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"/etc/ssh/ssh_host_ed25519_key.pub"
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"/etc/ssh/ssh_host_rsa_key"
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"/etc/ssh/ssh_host_rsa_key.pub"
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];
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};
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fileSystems."/".options = ["compress=zstd" "noatime" ];
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fileSystems."/nix".options = ["compress=zstd" "noatime" ];
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fileSystems."/persist".options = ["compress=zstd" "noatime" ];
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fileSystems."/persist".neededForBoot = true;
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fileSystems."/var/log".options = ["compress=zstd" "noatime" ];
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fileSystems."/var/log".neededForBoot = true;
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users.mutableUsers = false;
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# rollback results in sudo lectures after each reboot
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security.sudo.extraConfig = ''
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Defaults lecture = never
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'';
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# reset / at each boot
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# Note `lib.mkBefore` is used instead of `lib.mkAfter` here.
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boot.initrd.postDeviceCommands = pkgs.lib.mkBefore ''
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mkdir -p /mnt
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# We first mount the btrfs root to /mnt
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# so we can manipulate btrfs subvolumes.
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mount -o subvol=/ /dev/mapper/luksroot /mnt
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# While we're tempted to just delete /root and create
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# a new snapshot from /root-blank, /root is already
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# populated at this point with a number of subvolumes,
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# which makes `btrfs subvolume delete` fail.
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# So, we remove them first.
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#
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# /root contains subvolumes:
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# - /root/var/lib/portables
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# - /root/var/lib/machines
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#
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# I suspect these are related to systemd-nspawn, but
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# since I don't use it I'm not 100% sure.
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# Anyhow, deleting these subvolumes hasn't resulted
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# in any issues so far, except for fairly
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# benign-looking errors from systemd-tmpfiles.
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btrfs subvolume list -o /mnt/root |
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cut -f9 -d' ' |
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while read subvolume; do
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echo "deleting /$subvolume subvolume..."
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btrfs subvolume delete "/mnt/$subvolume"
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done &&
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echo "deleting /root subvolume..." &&
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btrfs subvolume delete /mnt/root
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echo "restoring blank /root subvolume..."
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btrfs subvolume snapshot /mnt/root-blank /mnt/root
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# Once we're done rolling back to a blank snapshot,
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# we can unmount /mnt and continue on the boot process.
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umount /mnt
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'';
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}
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