91 lines
2.6 KiB
Nix
91 lines
2.6 KiB
Nix
{
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impermanence,
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config,
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lib,
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pkgs,
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inTester,
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...
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}:
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with lib; {
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imports = ["${impermanence}/nixos.nix"];
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options = {
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environment.impermanence = mkEnableOption "Enables impermanence";
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};
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config = mkMerge [
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{
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environment.impermanence = mkDefault (!config.boot.isContainer && !inTester);
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}
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(mkIf config.environment.impermanence {
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boot.initrd.postDeviceCommands = mkAfter ''
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mkdir /btrfs_tmp
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mount ${config.fileSystems."/".device} -t btrfs /btrfs_tmp
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if [[ -e /btrfs_tmp/root ]]; then
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mkdir -p /btrfs_tmp/old_roots
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timestamp=$(date --date="@$(stat -c %Y /btrfs_tmp/root)" "+%Y-%m-%-d_%H:%M:%S")
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mv /btrfs_tmp/root "/btrfs_tmp/old_roots/$timestamp
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fi
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delete_subvolume_recursively() {
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IFS=$'\n'
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for i in $(btrfs subvolume list -o "$1" | cut -f 9- -d ' '); do
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delete_subvolume_recursively "/btrfs_tmp/$i"
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done
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btrfs subvolume delete "$1"
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}
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for i in $(find /btrfs_tmp/old_roots/ -maxdepth 1 -mtime +30); do
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delete_subvolume_recursively "$i"
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done
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btrfs subvolume create /btrfs_tmp/root
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umount /btrfs_tmp
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'';
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assertions = [
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{
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assertion = hasAttr "/" config.fileSystems;
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message = "To use impermanence, you need to define a root volume";
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}
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{
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assertion =
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if hasAttr "/" config.fileSystems
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then config.fileSystems."/".fsType == "btrfs"
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else false;
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message = "rootfs must be btrfs";
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}
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{
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assertion =
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if hasAttr "/" config.fileSystems
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then any (t: t == "subvol=root") config.fileSystems."/".options
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else false;
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message = "rootfs must mount subvolume root";
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}
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];
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fileSystems."/persistent" = {
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device =
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if hasAttr "/" config.fileSystems
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then mkDefault config.fileSystems."/".device
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else "/dev/null";
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fsType = "btrfs";
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options = ["subvol=persistent"];
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neededForBoot = true;
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};
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environment.persistence."/persistent" = {
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enable = true;
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hideMounts = true;
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directories = [
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"/var/log"
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"/var/lib/nixos"
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];
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files = [
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"/etc/ssh/ssh_host_ecdsa_key"
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"/etc/ssh/ssh_host_ecdsa_key.pub"
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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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})
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];
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}
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