61 lines
1.9 KiB
Nix
61 lines
1.9 KiB
Nix
{impermanence, ...}: {
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# Impermanence in NixOS is where the root directory isn't permanent, but gets
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# wiped every reboot (such as by mounting it as tmpfs). Such a setup is
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# possible because NixOS only needs /boot and /nix in order to boot, all
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# other system files are simply links to files in /nix.
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# The impermanence module bind-mounts persistent files and directories,
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# stored in /nix/persist, into the tmpfs root partition on startup. For
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# example: /nix/persist/etc/machine-id is mounted to /etc/machine-id.
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# https://github.com/nix-community/impermanence
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# https://nixos.wiki/wiki/Impermanence
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# https://elis.nu/blog/2020/05/nixos-tmpfs-as-root/
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imports = [
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impermanence.nixosModules.impermanence
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];
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# We *don't* want to use tmpfs for /tmp in case we have to put big files
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# there. Instead, we mount it to the disk and instruct systemd to clean it on
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# boot.
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# TODO: There might be a way to configure /tmp to be in-memory storage until
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# it gets too big.
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boot.tmp.cleanOnBoot = true;
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# Each module will configure the paths they need persisted. Here we define
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# some general system paths that don't really fit anywhere else.
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environment.persistence."/nix/persist" = {
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hideMounts = true;
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directories = [
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# See comment above for /tmp
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{
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directory = "/tmp";
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user = "root";
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group = "root";
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mode = "1777";
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}
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# Save the last run time of persistent timers so systemd knows if they were missed
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{
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directory = "/var/lib/systemd/timers";
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user = "root";
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group = "root";
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mode = "0755";
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}
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{
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directory = "/var/log";
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user = "root";
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group = "root";
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mode = "0755";
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}
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];
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files = [
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"/etc/machine-id" # needed for /var/log
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];
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users.caspervk = {
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directories = [
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"/" # entire home directory (TODO?)
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];
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};
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};
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}
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