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.gitignore

@@ -2,4 +2,4 @@
 # Ignore build outputs from performing a nix-build or `nix build` command
 result
 result-*
-
+.pre-commit-config.yaml

.sops.yaml

@@ -1,16 +1,33 @@
 keys:
   - &nerf age1rasjnr2tlv9y70sj0z0hwpgpxdc974wzg5umtx2pnc6z0p05u3js6r8sln
+  - &gonne age1epz92k2rkp43hkrg3u0jgkzhnkwx8y43kag7rvfzwl9wcddelvusyetxl7
 
   - &nyarlathotep age1s99d0vlj5qlm287n98jratql5fypvjrxxal0k5jl2aw9dcc8kyvqw5yyt4
+  - &bragi age1lqvgpmlemyg9095ujck64u59ma29656zs7a4yxgz4s6u5cld2ccss69jwe
+  - &lobon age12nz7dtc0m5wasxm4r9crtkgwnzvauyfp0xh0n8z8jld0arn9ea9qe0agvn
 
 creation_rules:
-  - path_regex nixos/machines/nyarlathotep/.*
+  - path_regex: nixos/machines/nyarlathotep/.*
     key_groups:
       - age:
-          *nerf
+        - *nerf
-          *nyarlathotep
+        - *gonne
+        - *nyarlathotep
+  - path_regex: nixos/machines/bragi/.*
+    key_groups:
+      - age:
+        - *nerf
+        - *gonne
+        - *bragi
+  - path_regex: nixos/machines/lobon/.*
+    key_groups:
+      - age:
+        - *nerf
+        - *gonne
+        - *lobon
   # this is the catchall clause if nothing above machtes. Encrypt to users but not
   # to machines
   - key_groups:
       - age:
-          *nerf
+        - *nerf
+        - *gonne

README.md

@@ -1,38 +1,311 @@
 # nixConfig
+This repository contains the configuration of all our machines running NixOS.
 
 ## Build a machine
+There are multiple ways to build and deploy a machine configuration. Which is the
+most appropriate depends on the context and scenario. So first there will be a general
+explanation how this works and afterwards we will talk about some scenarios.
+
+If you run `nix flake show`, you should get an output similar to this
+```
+$ nix flake show
+git+file:///home/nerf/git/nixConfig?ref=refs%2fheads%2fnyarlathtop&rev=9d0eb749287d1e9e793811759dfa29469ab706dc
+├───apps
+│   └───x86_64-linux
+├───checks
+│   └───x86_64-linux
+├───devShells
+│   └───x86_64-linux
+├───formatter
+├───legacyPackages
+│   └───x86_64-linux omitted (use '--legacy' to show)
+├───nixosConfigurations
+│   └───nyarlathotep: NixOS configuration
+├───nixosModules
+├───overlays
+└───packages
+    └───x86_64-linux
+```
+we can see there is an output called `nixosConfigurations.nyarlathotep` which contains the configuration of the machine
+called nyarlathotep. `nixosConfigurations` is special in that sense, that `nixos-rebuild` will automatically look
+for this key and assume how it is structured. The interesting part for us is the derivation `config.system.build.toplevel`.
+Its closure contains the whole system and the resulting derivation a script that changes the current system to
+that derivation. (called `/bin/switch-to-configuration`).
+
+So what we want to archive is populate the nix store of the target machine with the closure of the derivation
+`.#nixosConfigurations.<name>.config.system.build.toplevel` and run the the resulting script on the target machine.
+
+
 ### Local
-If you want to build the machineconfiguration for machine <name>
+It has multiple benefits to build the system configuration on the local computer and push it to the target server.
-run
+For example one doesn't stress the server with the load of evaluating the expression and building the closure. Also the server
+doesn't need to fetch the build dependencies this way. One has a local check if at least the nix syntax was correct.
+And so on...
+
+#### Build
+If you have this repository local in your current directory, you can just run
 ```
-nix build .#nixosConfiguration.<name>.config.system.build.toplevel
+$ nix build .#nixosConfigurations.<name>.config.system.build.toplevel
 ```
+to build the system configuration of the machine `<name>`.
+
+But you don't need to clone this repository, for more see the `nix flake --help` documentation about flake urls.
+
+#### Copy
+After we build the derivation we need to get the closure onto the target system. Luckily nix has tools to do that
+via ssh. We could just run:
+```
+$ nix copy -s --to <however you setup your ssh stuff> .#nixosConfigurations.<name>.config.system.build.toplevel
+```
+This will evaluate the flake again to get the store path of the given derivation. If we want to avoid this,
+we might supply the corresponding store path directly.
+
+The `-s` is important: it makes the target machine substitute all derivations it can (by default from chache.nixos.org).
+So you only upload configuration files and self build things.
+
+To be able to copy things to a machine they need to be signed by someone trusted. Additional trusted nix keys are handled
+in `./nixos/roles/nix_keys.nix`. So to get yourself trusted you either need to install one derivation from the machine itself,
+or find someone who is already trusted, to push your key.
+
+For more information on signing and key creation see `nix store sign --help` and `nix key --help`.
+
+#### Activate
+Log into the remote machine and execute (with root privileges)
+```
+# /nix/store/<storepath>/bin/switch-to-configuration boot
+```
+That will setup a configuration switch at reboot. You can also switch the configuration live. For more
+details consider the `--help` output of that script. The storepath (or at least the hash of the derivation)
+is exactly the same it was on your machine.
+
+
+If you have a `nixos-rebuild` available on your system, it can automatize these things with the `--flake` and
+`--target-host` parameters. But there are some pitfalls so look at the `nixos-rebuild` documentation beforehand.
 
 ### On the machine
-clone this repo to `/etc/nixos/` and `nixos-rebuild` that will select
+
-the appropriate machine based on hostname
+Clone this repository to `/etc/nixos/` and `nixos-rebuild boot` or `nixos-rebuild switch` that will select
+the appropriate machine based on hostname.
+
+If the hostname is not correct, or you don't want to clone this flake, you can also use the `--flake` parameter.
+
+In any case, to switch the system configuration you will need to have root privileges on the target machine.
+
+## Installing a new machine
+
+You have written a configuration and now want to deploy it as a new machine. You need to get the build configuration on the
+`nixos-installer` machine (regarding this machine see issue [#10]). You can either use either any of the
+versions above, or just continue then the machine will build the configuration implicitly.
+
+### Disk layout
+
+You will need to assemble the disk layout manually, we assume you do it below `/mnt` as the nixos-install tools
+assume this as the default location (they have an option to change that consider their `--help` pages).
+
+This repository loads some default configuration that expects certain things. Your hardware configuration of that machine should
+reflect those.
+
+- `"/"` is a tmpfs
+- `"/persist"` is the place where we keep data that can not be regenerated at any boot, so this should be a permanent disk
+- `"/nix"` the place the nixstore resides, needed to boot the machine should also be persistent
+- `"/boot"` the place for bootloader configuration and kernel also persistent
+- any additional data paths for your machine specific needs. Choose filesystems accordingly.
+
+My recommendation is to put `"/persist"` and `"/nix"` on a joint btrfs as subvolumes and `"/boot"` on separate disks (because grub
+will give you a hard time if you do it as a subvolume or bind mount (even though that should be possible but is an upstream problem)).
+For how to configure additional persistent data
+to be stored in `"/persist"` look at the impermanence section as soon it is merged. Before this look at issue [#9].
+I do not recommend this for actual high access application data like databases mailboxes and things like it. You should
+think about this as data that if lost can be regenerated with only little problems and read/written only a few times
+during setup. (Like the server ssh keys for example). The configuration also setups some paths for `"/persist"` automatically,
+again look at the impermanence sections.
+
+#### File system uuids
+
+You might end with a bit of a chicken/egg problem regarding filesystem uuids. See you need to set them in your system configuration.
+There are two ways around that. Either generate the filesystems read out the uuids, and push them into the repository holding
+the configuration you want to build, or generate the uuids first, have them in your configuration and set them upon filesystem creation. Most
+`mkfs` utilities have an option for that.
+
+### Installing
+
+Just run
+```
+nixos-install --flake 'git+https://gitea.mathebau.de/Fachschaft/nixConfig?ref=<branchname>#<name>'
+```
+where `<branchname>` is the branch you install from and `<name>` is the name of the configuration you build.
+If the build system is already in the nix store, this will start the installation, else it will first attempt to build
+it. That should be the whole installation process, just reboot. The machine should be fully setup. No additional user
+or service setup, after the reboot.
 
 
-### sops
+## How to write a new machine configuration
+At best, you take a first look at already existing configurations. But here are a few guidelines.
+Make a new folder in `/nixos/machines`. The name of the folder should match the hostname of your
+machine. The only technically required file in there is `configuration.nix`. So create it.
+
+A good skeleton is probably:
+```
+{config, pkgs, lib, flake-inputs, ... }: {
+
+imports = [
+  ./hardware-configuration.nix
+  ../../roles
+  ./network.nix
+
+  <your additional imports here>
+
+  ];
+
+  <your system config here>
+  networking.hostname = "<your hostname>"; # this will hopefully disappear if I have time to refactor this.
+  system.stateVersion = "<state version at time of install>";
+}
+```
+The import of `../../roles` loads all the nice default setup that all these machines have in common. There the
+impermanence configuration is loaded as well as ssh, sops, shared user configuration and much more.
+The other two imports are suggestions how you should organize your configuration but not enforced by anything.
+In your hardware
+configuration you should basically only write you filesystem layout and your hostPlatform. The bootloading stuff
+is already taken care of by `../../roles`.
+
+The `flake-inputs` argument is optional, but you can use it if you need to get a hold of the flake inputs,
+else this is a complete normal nixos system configuration module (with a lot of settings already imorted
+from `../../roles`).
+
+As of moment of writing `network.nix` should contain ip, nameserver and default gateway setup. As parts of
+this is constant across all systems and will undergo refactor soon.
+
+I would recommend to split your configuration into small files you import. If this is something machine specific (like
+tied to your ip address hostname), put it into the machine directory. If it is not, put it into `/nixos/roles/` if it
+is not but has options to set, put it in `/nixos/modules`.
+
+## How this flake is organized
+
+This flake uses `flake-parts` see [flake.parts](https://flake.parts) for more details. It makes handling
+`system` and some other modules related things more convenient.
+For the general layout of nixos system configuration and modules, please see the corresponding documentation.
+
+The toplevel `flake.nix` contains the flake inputs as usual and only calls a file `flake-module.nix`.
+This toplevel `flake-module.nix` imports further more specialized `flake-modules.nix` files from sub-directories.
+Right now the only one is `nixos/flake-module.nix`. But if we start to ship our own software (or software versions,
+with specific build flags), this might get more.
+
+### nixos
+The `nixos` folder contains all machine configurations. It separates in two folders `nixos/machines` and `nixos/roles`.
+The corresponding `flake-module.nix` file automatically searches for `machines/<name>/configuration.nix`, and evalutes
+those as nixos configurations, and populates the flake.
+
+#### machines
+`nixos/machines` contains all machine specific configuration (in a sub-folder per machine). Like hardware configuration, specific
+network configuration. And service configuration that are too closely interwoven with the rest of that machine (for example
+mailserver configuration depends heavily on network settings). It also
+contains the root configuration for that machine called `configuration.nix`. This file usually only includes other modules.
+These `configuration.nix` files are almost usual nix configurations. The only difference is that they take as an extra argument
+the flake inputs. This allows them to load modules from these flakes. For example, nyarlathotep loads the simple-nixos-mailserver
+module that way.
+
+#### roles
+`nixos/roles` contains configuration that is potentially shared by some machines. It is expected that `nixos/roles/default.nix`
+is imported as (`../../roles`) in every machine. Notable are the files `nixos/roles/admins.nix` which contains
+common admin accounts for these machines and `nixos/roles/nix_keys.nix` which contains the additional trusted
+keys for the nix store.
+
+## sops
 
 We are sharing secrets using [`sops`](https://github.com/getsops/sops) and [`sops-nix`](https://github.com/Mic92/sops-nix)
 As of right now we use only `age` keys.
 The machine keys are derived from their server ssh keys, that they generate at first boot.
+To read out a machines public key run the following command on the corresponding machine.
+```
+$ nix-shell -p ssh-to-age --run 'cat /etc/ssh/ssh_host_ed25519_key.pub | ssh-to-age'
+```
 User keys are generated by the users.
-New keys and machines need entries into the `.sops.yaml` file within the root directory of this repo.
+New keys and machines need entries into the `.sops.yaml` file within the root directory of this repository.
 
-To make a secret available on a given machine you need to do the following. Configure the following keys
+To make a secret available on a given machine you need to configure the following:
 
 ```
 sops.secrets.example-key = {
-  sopsFile = "relative path to file in the repo containing the secrets (optional else the sops.defaultSopsFile is used)
+  sopsFile = "relative path to file in the repo containing the secrets (optional else the sops.defaultSopsFile is used)";
-  path = "optinal path where the secret gets symlinked to, practical if some programm expects a specific path"
+  path = "optinal path where the secret gets symlinked to, practical if some program expects a specific path";
-  owner = user that owns the secret file: config.users.users.nerf.name (for example)
+  owner = user that owns the secret file: config.users.users.nerf.name (for example);
-  group = same as user just with groups: config.users.users.nerf.group
+  group = same as user just with groups: config.users.users.nerf.group;
-  mode = "premission in usual octet: 0400 (for example)"
+  mode = "permission in usual octet: 0400 (for example)";
+};
 ```
-afterwards the secret should be available in `/run/secrets/example-key`.
+Afterwards the secret should be available in `/run/secrets/example-key`.
 If the accessing process is not root it must be member of the group `config.users.groups.keys`
 for systemd services this can be archived by setting `serviceConfig.SupplementaryGroups = [ config.users.groups.keys.name ];`
-it the service config.
+it the service configuration.
 
+## impermanence
+
+These machines are setup with `"/"` as a tmpfs. This is there to keep the machines clean. So no clutter in home
+directories, no weird ad-hoc solutions of botching something into `/opt/` or something like this. All will be
+gone at reboot.
+
+But there are some files that we want to survive reboots, for example logs or ssh keys. The solution to this is
+to have a persistent storage mounted at `/persist` and automatically bind mount the paths of persistent things
+to the right places. To set this up we are using the impermanence module. In our configuration this is loaded with
+some default files to bind mount (ssh keys, machine-id some nixos specific things). That we have on all machines.
+
+If you keep your application data (like recommended) on a separate partition, the chances are you don't need
+to interact with this, as most configuration files will be in the nix store anyway. If the application wants these nix
+store files in certain directories, you should use `environment.etc` family of options (consult the nixos documentation
+for this). This is for mutable files that are not core application data. (Like ssh keys, for a mailserver one could
+think about the hash files (not the db files) of an alias map (if one doesn't want to manage that with
+the nix store), things like that).
+
+This should not be (but could be) used for large application databases. It would be more appropriate to mount
+its own filesystem for things like that. For small configuration files that are not in the nix-store,
+that might be the appropriate solution.
+
+By default the storage is called `persist` and the default path for it is `/persist`. These can be changed
+with the `impermanence.name` and `impermanence.storagePath` options. To add paths to this storage you do the
+following.
+
+```
+environment.persistence.${config.impermanence.name} = {
+  directories = [
+    "<your path to a directory to persist>"
+  ];
+  files = [
+    "<your path to a file to persist>"
+  ];
+};
+```
+For this to work `config` must be binded by the function arguments of you module. So the start of your module looks
+something like this:
+```
+{lib, pkgs, config, ...} :
+<module code >
+```
+
+# Contributing
+
+Like with all FS projects, you are welcome to contribute. Work is done usually by the person that is most annoyed
+by the circumstances or by the person that didn't run fast enough. So we are happy if we get help. That doesn't
+mean that we don't need to have some level of quality, people after us needs to work with it. It is live infrastructure
+and downtime hurts someone (and in the wrong moment even really bad (Matheball ticket sales for example)).
+
+So here are some Guidelines.
+
+## Coding style and linting.
+If you run `nix flake check` there are automated checks in place, please make sure to pass them.
+There is also a code autoformatter (`alejandra`) incorporated into those. If you want to run
+it you can do so over the development shell or by running `nix fmt`.
+You can also install
+them into your local git repository as pre-commit hooks, and setting up a shell that has
+even more tooling by running `nix develop`. That will give you a bash in which you can run
+all the checks manually `pre-commit run -a`. This will also run the autoformatter.
+
+## Process for submitting changes
+
+1. If it is something bigger, please open an issue first describing what and why you want to do something.
+   If it is just something small, skip this step.
+2. Fork the repo and implement your changes in a branch on your fork. Afterwards open a pull request (possibly mentioning the issue).
+   Against the main branch.
+   - Your branch should be based on an up to date version of main, if it is not consider rebasing.
+3. You will need to find someone with the proper rights to approve of your changes, but most of the time there will be request
+   for changes first.

flake-module.nix

@@ -1,28 +1,66 @@
-{inputs, ...}:
+{inputs, ...}: {
-{
   # debug = true;
   # We only define machines config in this flake yet, so we only include
   # the module that builds these. This file might get fuller, if we need to
   # build our own packages, that are not flakes.
-  imports = [ ./nixos/flake-module.nix
+  imports = [
+    ./nixos/flake-module.nix
+    inputs.pre-commit-hooks.flakeModule
     # To import a flake module
     # 1. Add foo to inputs
     # 2. Add foo as a parameter to the outputs function
     # 3. Add here: foo.flakeModule
-
   ];
-  systems = [ "x86_64-linux"];
+  systems = ["x86_64-linux"];
-#  perSystem = { config, self', inputs', pkgs, system, ... }: {
+  perSystem = {
+    config,
+    pkgs,
+    system,
+    ...
+  }: {
+    devShells.default = config.pre-commit.devShell;
+
+    pre-commit = let
+      generatedFiles = [
+        "hardware-configuration\\.nix"
+      ];
+    in {
+      check.enable = true;
+      settings = {
+        hooks = {
+          nil.enable = true;
+          statix = {
+            enable = true;
+            settings = {
+              format = "stderr";
+              ignore = generatedFiles;
+            };
+          };
+          deadnix = {
+            enable = true;
+            excludes = generatedFiles;
+          };
+          alejandra.enable = true;
+        };
+      };
+    };
+
+    formatter = pkgs.alejandra;
+
     # Per-system attributes can be defined here. The self' and inputs'
     # module parameters provide easy access to attributes of the same
     # system.
+    _module.args.pkgs = import inputs.nixpkgs {
+      inherit system;
+      config.permittedInsecurePackages = ["jitsi-meet-1.0.8043"];
+    };
+  };
 
   # Equivalent to  inputs'.nixpkgs.legacyPackages.hello;
-#  };
+  #      flake = {
-#      flake = {
   # The usual flake attributes can be defined here, including system-
   # agnostic ones like nixosModule and system-enumerating ones, although
   # those are more easily expressed in perSystem.
 
-#      };
+  #      };
 }

flake.lock

@@ -21,11 +21,11 @@
         "nixpkgs-lib": "nixpkgs-lib"
       },
       "locked": {
-        "lastModified": 1685662779,
+        "lastModified": 1727826117,
-        "narHash": "sha256-cKDDciXGpMEjP1n6HlzKinN0H+oLmNpgeCTzYnsA2po=",
+        "narHash": "sha256-K5ZLCyfO/Zj9mPFldf3iwS6oZStJcU4tSpiXTMYaaL0=",
         "owner": "hercules-ci",
         "repo": "flake-parts",
-        "rev": "71fb97f0d875fd4de4994dfb849f2c75e17eb6c3",
+        "rev": "3d04084d54bedc3d6b8b736c70ef449225c361b1",
         "type": "github"
       },
       "original": {
@@ -33,20 +33,34 @@
         "type": "indirect"
       }
     },
+    "impermanence": {
+      "locked": {
+        "lastModified": 1727649413,
+        "narHash": "sha256-FA53of86DjFdeQzRDVtvgWF9o52rWK70VHGx0Y8fElQ=",
+        "owner": "nix-community",
+        "repo": "impermanence",
+        "rev": "d0b38e550039a72aff896ee65b0918e975e6d48e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "impermanence",
+        "type": "github"
+      }
+    },
     "nixos-mailserver": {
       "inputs": {
         "blobs": "blobs",
         "flake-compat": [],
         "nixpkgs": [],
-        "nixpkgs-22_11": "nixpkgs-22_11",
+        "nixpkgs-24_05": "nixpkgs-24_05"
-        "utils": "utils"
       },
       "locked": {
-        "lastModified": 1686468558,
+        "lastModified": 1722877200,
-        "narHash": "sha256-K69Ojlx3N8I6tRTZsrKFMIqK4yrnJ6/PjfKZi3wchYg=",
+        "narHash": "sha256-qgKDNJXs+od+1UbRy62uk7dYal3h98I4WojfIqMoGcg=",
         "ref": "refs/heads/master",
-        "rev": "290d00f6db4e80467013728819ad73dd4a394d9a",
+        "rev": "af7d3bf5daeba3fc28089b015c0dd43f06b176f2",
-        "revCount": 554,
+        "revCount": 593,
         "type": "git",
         "url": "https://gitlab.com/simple-nixos-mailserver/nixos-mailserver.git"
       },
@@ -57,11 +71,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1686412476,
+        "lastModified": 1728492678,
-        "narHash": "sha256-inl9SVk6o5h75XKC79qrDCAobTD1Jxh6kVYTZKHzewA=",
+        "narHash": "sha256-9UTxR8eukdg+XZeHgxW5hQA9fIKHsKCdOIUycTryeVw=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "21951114383770f96ae528d0ae68824557768e81",
+        "rev": "5633bcff0c6162b9e4b5f1264264611e950c8ec7",
         "type": "github"
       },
       "original": {
@@ -71,60 +85,77 @@
         "type": "github"
       }
     },
-    "nixpkgs-22_11": {
+    "nixpkgs-24_05": {
       "locked": {
-        "lastModified": 1669558522,
+        "lastModified": 1717144377,
-        "narHash": "sha256-yqxn+wOiPqe6cxzOo4leeJOp1bXE/fjPEi/3F/bBHv8=",
+        "narHash": "sha256-F/TKWETwB5RaR8owkPPi+SPJh83AQsm6KrQAlJ8v/uA=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "ce5fe99df1f15a09a91a86be9738d68fadfbad82",
+        "rev": "805a384895c696f802a9bf5bf4720f37385df547",
         "type": "github"
       },
       "original": {
         "id": "nixpkgs",
-        "ref": "nixos-22.11",
+        "ref": "nixos-24.05",
         "type": "indirect"
       }
     },
     "nixpkgs-lib": {
       "locked": {
-        "dir": "lib",
+        "lastModified": 1727825735,
-        "lastModified": 1685564631,
+        "narHash": "sha256-0xHYkMkeLVQAMa7gvkddbPqpxph+hDzdu1XdGPJR+Os=",
-        "narHash": "sha256-8ywr3AkblY4++3lIVxmrWZFzac7+f32ZEhH/A8pNscI=",
+        "type": "tarball",
-        "owner": "NixOS",
+        "url": "https://github.com/NixOS/nixpkgs/archive/fb192fec7cc7a4c26d51779e9bab07ce6fa5597a.tar.gz"
-        "repo": "nixpkgs",
-        "rev": "4f53efe34b3a8877ac923b9350c874e3dcd5dc0a",
-        "type": "github"
       },
       "original": {
-        "dir": "lib",
+        "type": "tarball",
-        "owner": "NixOS",
+        "url": "https://github.com/NixOS/nixpkgs/archive/fb192fec7cc7a4c26d51779e9bab07ce6fa5597a.tar.gz"
-        "ref": "nixos-unstable",
-        "repo": "nixpkgs",
-        "type": "github"
       }
     },
     "nixpkgs-stable": {
       "locked": {
-        "lastModified": 1694908564,
+        "lastModified": 1728156290,
-        "narHash": "sha256-ducA98AuWWJu5oUElIzN24Q22WlO8bOfixGzBgzYdVc=",
+        "narHash": "sha256-uogSvuAp+1BYtdu6UWuObjHqSbBohpyARXDWqgI12Ss=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "596611941a74be176b98aeba9328aa9d01b8b322",
+        "rev": "17ae88b569bb15590549ff478bab6494dde4a907",
         "type": "github"
       },
       "original": {
         "owner": "NixOS",
-        "ref": "release-23.05",
+        "ref": "release-24.05",
         "repo": "nixpkgs",
         "type": "github"
       }
     },
+    "pre-commit-hooks": {
+      "inputs": {
+        "flake-compat": [],
+        "gitignore": [],
+        "nixpkgs": [],
+        "nixpkgs-stable": []
+      },
+      "locked": {
+        "lastModified": 1728727368,
+        "narHash": "sha256-7FMyNISP7K6XDSIt1NJxkXZnEdV3HZUXvFoBaJ/qdOg=",
+        "owner": "cachix",
+        "repo": "pre-commit-hooks.nix",
+        "rev": "eb74e0be24a11a1531b5b8659535580554d30b28",
+        "type": "github"
+      },
+      "original": {
+        "owner": "cachix",
+        "repo": "pre-commit-hooks.nix",
+        "type": "github"
+      }
+    },
     "root": {
       "inputs": {
         "flake-parts": "flake-parts",
+        "impermanence": "impermanence",
         "nixos-mailserver": "nixos-mailserver",
         "nixpkgs": "nixpkgs",
+        "pre-commit-hooks": "pre-commit-hooks",
         "sops-nix": "sops-nix"
       }
     },
@@ -136,11 +167,11 @@
         "nixpkgs-stable": "nixpkgs-stable"
       },
       "locked": {
-        "lastModified": 1695284550,
+        "lastModified": 1728345710,
-        "narHash": "sha256-z9fz/wz9qo9XePEvdduf+sBNeoI9QG8NJKl5ssA8Xl4=",
+        "narHash": "sha256-lpunY1+bf90ts+sA2/FgxVNIegPDKCpEoWwOPu4ITTQ=",
         "owner": "Mic92",
         "repo": "sops-nix",
-        "rev": "2f375ed8702b0d8ee2430885059d5e7975e38f78",
+        "rev": "06535d0e3d0201e6a8080dd32dbfde339b94f01b",
         "type": "github"
       },
       "original": {
@@ -148,21 +179,6 @@
         "repo": "sops-nix",
         "type": "github"
       }
-    },
-    "utils": {
-      "locked": {
-        "lastModified": 1605370193,
-        "narHash": "sha256-YyMTf3URDL/otKdKgtoMChu4vfVL3vCMkRqpGifhUn0=",
-        "owner": "numtide",
-        "repo": "flake-utils",
-        "rev": "5021eac20303a61fafe17224c087f5519baed54d",
-        "type": "github"
-      },
-      "original": {
-        "owner": "numtide",
-        "repo": "flake-utils",
-        "type": "github"
-      }
     }
   },
   "root": "root",

flake.nix

@@ -14,8 +14,20 @@
       url = "github:Mic92/sops-nix";
       inputs.nixpkgs.follows = "nixpkgs";
     };
+    impermanence = {
+      url = "github:nix-community/impermanence";
+    };
+    pre-commit-hooks = {
+      url = "github:cachix/pre-commit-hooks.nix";
+      inputs = {
+        flake-compat.follows = "";
+        gitignore.follows = "";
+        nixpkgs-stable.follows = "";
+        nixpkgs.follows = "";
+      };
+    };
   };
 
-  outputs = inputs@{ flake-parts, ... }:
+  outputs = inputs @ {flake-parts, ...}:
-    flake-parts.lib.mkFlake { inherit inputs; } (import ./flake-module.nix);
+    flake-parts.lib.mkFlake {inherit inputs;} (import ./flake-module.nix);
 }

nixos/flake-module.nix

@@ -1,19 +1,30 @@
 # copied and adopted from maralorns config
-
 # This automatically searches for nixos configs in ./machines/${name}/configuration.nix
 # and exposes them as outputs.nixosConfigurations.${name}
-{ withSystem, lib, inputs, ... }: {
+{
+  withSystem,
+  lib,
+  inputs,
+  ...
+}: {
   flake = {
-    nixosConfigurations = withSystem "x86_64-linux" ({ pkgs, ... }:
+    nixosConfigurations = withSystem "x86_64-linux" ({pkgs, ...}: let
-    let
       machines = builtins.attrNames (builtins.readDir ./machines);
-      makeSystem = name:
+      makeSystem = name: let
+        importedConfig = import (./. + "/machines/${name}/configuration.nix");
+        systemConfig =
+          if lib.isFunction importedConfig
+          then x: importedConfig (x // {flake-inputs = inputs;})
+          else importedConfig;
+      in
         pkgs.nixos {
           imports = [
-            (import (./. + "/machines/${name}/configuration.nix") inputs)
+            systemConfig
             inputs.sops-nix.nixosModules.sops
+            inputs.impermanence.nixosModules.impermanence
           ];
         };
-    in lib.genAttrs machines makeSystem);
+    in
+      lib.genAttrs machines makeSystem);
   };
 }

nixos/machines/bragi/backupKey.yaml

@@ -0,0 +1,39 @@
+backupKey: ENC[AES256_GCM,data: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,iv:ZdivBorDtIyBOs7XSg/DHjReG+T6/exeS8ziA7ms7FM=,tag:gcIXgpyd2UeQV3APqCCxMg==,type:str]
+sops:
+    kms: []
+    gcp_kms: []
+    azure_kv: []
+    hc_vault: []
+    age:
+        - recipient: age1rasjnr2tlv9y70sj0z0hwpgpxdc974wzg5umtx2pnc6z0p05u3js6r8sln
+          enc: |
+            -----BEGIN AGE ENCRYPTED FILE-----
+            YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSBaR2dRc3NPeUwwaHdCL25V
+            RHNaWU9xRUw5dDlaOG5hczVlNm5UR01QUEVNClJsVFRBWU85Z0JuV1l3MDdvd1F2
+            RS9CcXhuNEJWdEE1cktXYjF3RW9wUDQKLS0tIHk3MURmWlJNanVZaHlUR3R2UEZG
+            K2JxOHpNY2hsTysrWjNLajFKQkxuNHcKaFMvnDt9a3HsnbP1Q/i4ifRIXFcXYn8z
+            YyOho0hSmWZNhTbltmuVKjvCNgt9ONVRW93uRDDoju8Odps0qwwvuA==
+            -----END AGE ENCRYPTED FILE-----
+        - recipient: age1epz92k2rkp43hkrg3u0jgkzhnkwx8y43kag7rvfzwl9wcddelvusyetxl7
+          enc: |
+            -----BEGIN AGE ENCRYPTED FILE-----
+            YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSBMM1NCbHdFZDJvYjJjcmZ6
+            bUFjSG5OUEdydS9pTkNHRjFKb3gvWll0Q0RVCk56ZnhDa0NGeUNhVVdDZENieDFW
+            Q0xSNXhYQXZSVnI3WlRzUjhxOXRyM2sKLS0tIGhnVWJaRG4vSGpUcnQ5SFVFT3VQ
+            YUFzTlNLSE9CbW9oYTFsY0tpTE4vZTQKjurd87tDH8z58pAGJyVXRAu8Q2+k7e4G
+            zOGZhm5DpSmFv2O2fqXgBg8nT5wrPKQDFvcDh1P+a0753tUTbUttIA==
+            -----END AGE ENCRYPTED FILE-----
+        - recipient: age1lqvgpmlemyg9095ujck64u59ma29656zs7a4yxgz4s6u5cld2ccss69jwe
+          enc: |
+            -----BEGIN AGE ENCRYPTED FILE-----
+            YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSBlWmlwS0E5TytFdEpxN09U
+            Y3k0SDhnM2h5Rnh1bXQ2czA5bWt1Mkk3aUFFCmtwT2ZmN0IweGdOYURWNDVHcWtH
+            R3lRaFRkcWYzb2g4NWNFQU5WOXZZaGMKLS0tIHpWNnNvVUNucE5MQ1cxQWl6Qm1x
+            NUZDVnJORXF1NGlyNUkzOGl2REFHdmsK18k9UfOmtFSep6mZcSp6di7SjvrBXgGp
+            oWtLehp1UFEHCgaU5YxlYhtkrrOhb8ykFb1on+kmzrloaHqyvks7Aw==
+            -----END AGE ENCRYPTED FILE-----
+    lastmodified: "2024-03-21T16:38:08Z"
+    mac: ENC[AES256_GCM,data:kEVWd988Ia6T8v3w0slQhM0lh78VhnP8qJNa6IZg0NF2B0JQbFRnQNbUfvG9Rf4mkAR/O9PD+r6HR+b3LCwzb/Ok/eD4/M3+oPaEx/JnoHrzF/1N29VEAvBHjQgw6DL05toqu5G03UDcDUFGc111AeRsexhONQRHJx3zqWyWGy4=,iv:T5Pkhl3vhSAIoKkC3r3VQn3tC4t04WxvAZDQ4PMvD84=,tag:h0/aB91SFr5q0Or5daxWUQ==,type:str]
+    pgp: []
+    unencrypted_suffix: _unencrypted
+    version: 3.8.1

nixos/machines/bragi/configuration.nix

@@ -0,0 +1,22 @@
+{config, ...}: {
+  imports = [
+    ./hardware-configuration.nix
+    ../../roles
+    ../../roles/hardware.nix
+    ./network.nix
+    ../../modules/borgbackup.nix
+  ];
+
+  services.mathebau-borgbackup.enable = true;
+
+  # System configuration here
+  networking.hostName = "bragi";
+  system.stateVersion = "23.11";
+
+  sops.secrets.backupKey = {
+    sopsFile = ./backupKey.yaml;
+    owner = config.users.users.fsaccount.name;
+    inherit (config.users.users.fsaccount) group;
+    mode = "0400";
+  };
+}

nixos/machines/bragi/hardware-configuration.nix

@@ -0,0 +1,32 @@
+{lib, ...}: {
+  fileSystems."/" = {
+    device = "root";
+    fsType = "tmpfs";
+    options = ["size=2G" "mode=755"];
+  };
+  fileSystems."/persist" = {
+    device = "/dev/disk/by-label/nixos";
+    fsType = "btrfs";
+    options = ["subvol=persist"];
+    neededForBoot = true;
+  };
+  fileSystems."/boot" = {
+    device = "/dev/disk/by-label/boot";
+    fsType = "ext4";
+  };
+  fileSystems."/nix" = {
+    device = "/dev/disk/by-label/nixos";
+    fsType = "btrfs";
+    options = ["subvol=nix"];
+  };
+  fileSystems."/var/lib/backups" = {
+    device = "/dev/disk/by-label/backups";
+    fsType = "btrfs";
+  };
+
+  swapDevices = [{device = "/dev/disk/by-label/swap";}];
+
+  boot.loader.grub.device = "/dev/disk/by-id/wwn-0x5000c5003891662c";
+
+  nixpkgs.hostPlatform = lib.mkDefault "x86_64-linux";
+}

nixos/machines/bragi/network.nix

@@ -0,0 +1,16 @@
+# We sohuld put that config somewhere in roles and give it a parameter or something,
+# everyone gets the same nameserver and the same prefixLength and address vs defaultGateway alsways
+# depend on the same thing
+{
+  networking = {
+    interfaces.enp0s25.ipv4.addresses = [
+      {
+        address = "192.168.1.11";
+        prefixLength = 24;
+      }
+    ];
+    defaultGateway = "192.168.1.137";
+    # https://www.hrz.tu-darmstadt.de/services/it_services/nameserver_dns/index.de.jsp
+    nameservers = ["130.83.22.63" "130.83.22.60" "130.83.56.60"];
+  };
+}

nixos/machines/ghatanothoa/configuration.nix

@@ -0,0 +1,19 @@
+{
+  imports = [
+    ./hardware-configuration.nix
+    ../../modules/jitsi.nix
+    ../../roles
+    ../../roles/vm.nix
+    ../../modules/vmNetwork.nix
+  ];
+
+  services.mathebau-jitsi = {
+    enable = true;
+    hostName = "meet.mathebau.de";
+  };
+
+  # System configuration here
+  networking.hostName = "ghatanothoa";
+  vmNetwork.ipv4 = "192.168.0.25";
+  system.stateVersion = "23.11";
+}

nixos/machines/ghatanothoa/hardware-configuration.nix

@@ -0,0 +1,30 @@
+{lib, ...}: {
+  imports = [];
+
+  fileSystems."/" = {
+    device = "gha-root";
+    fsType = "tmpfs";
+    options = ["size=1G" "mode=755"];
+  };
+  fileSystems."/persist" = {
+    device = "/dev/disk/by-uuid/e0a160ef-7d46-4705-9152-a6b602898136";
+    fsType = "btrfs";
+    options = ["subvol=persist"];
+    neededForBoot = true;
+  };
+  fileSystems."/boot" = {
+    device = "/dev/disk/by-uuid/19da7f3a-69da-4fa8-bb68-b355d7697ba7";
+    fsType = "ext4";
+  };
+  fileSystems."/nix" = {
+    device = "/dev/disk/by-uuid/e0a160ef-7d46-4705-9152-a6b602898136";
+    fsType = "btrfs";
+    options = ["subvol=nix"];
+  };
+
+  swapDevices = [{device = "/dev/disk/by-uuid/e6e3ba6b-c9f5-4960-b56d-f49760d76a4a";}];
+
+  nix.settings.max-jobs = lib.mkDefault 4;
+
+  nixpkgs.hostPlatform = lib.mkDefault "x86_64-linux";
+}

nixos/machines/lobon/allowlistPass.yaml

@@ -0,0 +1,39 @@
+allowlistPass: ENC[AES256_GCM,data:bb9jXSvWeDnZqqiY/IarwA==,iv:qeFAYvXYdh2uEleg8kpCd77u4PTbwM8ydEkbMhyPz1I=,tag:1/eysyZb2mJ0mYHXIrpihw==,type:str]
+sops:
+    kms: []
+    gcp_kms: []
+    azure_kv: []
+    hc_vault: []
+    age:
+        - recipient: age1rasjnr2tlv9y70sj0z0hwpgpxdc974wzg5umtx2pnc6z0p05u3js6r8sln
+          enc: |
+            -----BEGIN AGE ENCRYPTED FILE-----
+            YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSAySVhjV0xXdGE2am85RVJh
+            NXJLRy92blkzeENuWHh3QSsxNHBXcUpibGxnCnVHUEVoYVgxbk5WSmxQRXNzMC9i
+            Y1g4MUFrNEVjVjJWM0xhU0JzTzNZTk0KLS0tIFIrdmhrbXFHb2VaQ1p2dDJMMmlR
+            Um5CcGlZanBBRzJKOVNZeWVPTmsrcVUK905uViHD7uZMVQHPfFraIHXYTHaT+ERl
+            ZvyRDdjjRCyxu0qcIpYVpPAmfGCo0++bXSRUX8rCp48YN20MbPNjgA==
+            -----END AGE ENCRYPTED FILE-----
+        - recipient: age1xv5rfxkxg9jyqx5jg2j82cxv7w7ep4a3795p4yl5fuqf38f3m3eqfnefju
+          enc: |
+            -----BEGIN AGE ENCRYPTED FILE-----
+            YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSBLNkNpN2RlcHBuOUxoYmkx
+            QzdOM1E0cFBSc1I0NzVRbmhiUXhjM3dQOWhnCmlOQzJ3b2Q5NFJkb2haMDNGSFBv
+            SkdySWtRUzhic1FNeXhiUFBPRVNoWmcKLS0tIGNaVW5xUmxWOEtXVkRqVEJJSEVv
+            NFBWREFQbnFXclhiNW51M0ZsOEMxdnMKdOPVRbD42q7MRw1CX1M30Xdil7VFLDVD
+            G8j4sjxlDkcwQK/3WjZdBLXAzJcrvAp0okGzw8lymC812CXTSEfmxw==
+            -----END AGE ENCRYPTED FILE-----
+        - recipient: age12nz7dtc0m5wasxm4r9crtkgwnzvauyfp0xh0n8z8jld0arn9ea9qe0agvn
+          enc: |
+            -----BEGIN AGE ENCRYPTED FILE-----
+            YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSBKVVN2THloaU1pVnhtWDhm
+            TWpPaHNLSXlud0RLU3ovS0s4REtUTzQwMHhZClF5OFZQVHB2VG9BeThSYzVSMUFJ
+            VDNkT0Y1Y3RUemkwSmxlM0drUlNDR1UKLS0tIDYrcVhXMWJxR2dhcXhjdTQ3MjV1
+            Y3lWbHdLOGRGamhRY0xoRnVJczc2aFUKWWAflRwoszNw5bEDTSaVI65FtQve/HrC
+            uY1JvYwXLq4m4hu76dyrplDpzb8ant/YAUXpG6F4U7nn9GiLBaoyUQ==
+            -----END AGE ENCRYPTED FILE-----
+    lastmodified: "2024-03-31T14:34:54Z"
+    mac: ENC[AES256_GCM,data:sjWiO96NcFUT4L9mdBuQwt6Zl5cS16o73zes30SYJxzM1R3ZBIg9oOmhXxY9BC3yKjEb6bVuemj/bnnopSR/m3RPH7xfaYCBfz97Zgc4SGtoqLIra5OUCRpWnKSsD6Nf09Qss5Pbla9EIrI0kQt7fpf4iKLF7VJwrQryslnvfcM=,iv:ilnbLK6sttweEyqszVHxVnjbTq8jF5ZTO24OEIPMprE=,tag:3XgAlXMl/RIaUfkVwHJeBQ==,type:str]
+    pgp: []
+    unencrypted_suffix: _unencrypted
+    version: 3.8.1

nixos/machines/lobon/backupKey.yaml

@@ -0,0 +1,39 @@
+backupKey: ENC[AES256_GCM,data:/PErHUVZDTyqK+GKI2inDoEBQpSmezeBTgXWnrthc8IPtUFn4Ur2CkDo+MqfiAlSn9vT2ksHmyS5qmoGANG01e1Cm50qpt/BdoC2hh15jOVuc0uUBNOq7f5YBVeYtbemwjPcmbF7dgUeRlEAvxhqtX3/ntzxSB1inew/SsEgPrU4Yl0FF+CHhqgbeB/NJOhQY29/3hBGwMksfTUDymUmX6pUgIN1M26crIKFCn5IyqAXl10F+zL4PThZPnhmks7Y8BsGUbKkiE6ghdaUjEjBjGOGgbaGAjolG+nJ17xyM1Pc2speT4E/3VgAC34dpaByveGcf2SfsXir0KavcI86mUkjzaNF9u7GjGO0Szn742/aqbdUoOkJl41unb0Enf2/D4Up3fy6LrUqVqrHIM4Dea9WLQd0poD0FWSN12IKh+ylkouMkmhwLXUXFzIHOePS92/MsPM+9fLhH4cU64qxr9UzmfYRnNBpAHrjlxdkK9WZ1Oj4mdtu6R20vYkYcMIQgU38FvSN6uWGvPxJj+Ij,iv:ghvgkC6qFO/0tvsc7igCoZy7am8eNsd21WYCSAKiZDs=,tag:MFnk/Nnw+cloN+x7sd4LLg==,type:str]
+sops:
+    kms: []
+    gcp_kms: []
+    azure_kv: []
+    hc_vault: []
+    age:
+        - recipient: age1rasjnr2tlv9y70sj0z0hwpgpxdc974wzg5umtx2pnc6z0p05u3js6r8sln
+          enc: |
+            -----BEGIN AGE ENCRYPTED FILE-----
+            YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSBaNVExTHQrY2h1M3RZOEdU
+            Wm5kdDBHZ1NmZGpQU0VOYWtjOTdBVURQZkJnCmZzWTEvSWxvMFk4NlFOVnBDbm9q
+            Tncva0VyMGVDL29ZZ0YxeGE3RFBUS3cKLS0tIDluK05NMUNNM3pEUmlCNE9BV3lT
+            L0dPYTBwbjJzUmJnYktiM2JBME5LM3cKvPwth4DxQgFYhvr9vJLfeaiNc+UfAo4c
+            RdXPLkwtq3vksrU1IR54tHcUJ0yZiZ1HxxGp3PCPaXXJiUykllnJPw==
+            -----END AGE ENCRYPTED FILE-----
+        - recipient: age1epz92k2rkp43hkrg3u0jgkzhnkwx8y43kag7rvfzwl9wcddelvusyetxl7
+          enc: |
+            -----BEGIN AGE ENCRYPTED FILE-----
+            YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSBRdFV0OVA5VTBuOVhsL3lp
+            MFpDN2RHVDExck5vcWpDNDNPM2k3S1FqQUFFCjNreXdSbDFXOHJ4b21mNGlZb0xQ
+            YUh0WVNGN2o1aFVaaGpxbmk4aUQ4ZTAKLS0tIHhtci84Zk1zZlBOOHk4a3VKUlM1
+            MXNZbWdpVEJiTTlIRERLYzBlNWxBMlUK4Z8JLlN5FOegfdg5njhHjbCwAm/f+kJS
+            buOHGWzWirW0ZibOP+fikzJwdIzIsX8v8tGaV89nQwf0hrxK0748Hg==
+            -----END AGE ENCRYPTED FILE-----
+        - recipient: age12nz7dtc0m5wasxm4r9crtkgwnzvauyfp0xh0n8z8jld0arn9ea9qe0agvn
+          enc: |
+            -----BEGIN AGE ENCRYPTED FILE-----
+            YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSBZa2pUZlZsVmhPU242d0Nj
+            bi9BSlJBU1Q1cFU4ZjA4NnlJNmdwaVFBc2xNCjJlSG5UaDFnSzFHZ01RVVNjOHY5
+            L1JVUit6SThvbGRIU0loNmtZanllNXcKLS0tIFhMR1pxRmlGQWFEQURiRFJoMWJZ
+            dlExV2xTVWR6bWI3VCtSdU81SmtqYncKLFQczlIj89vzlfgE33w6ktotYFdxaWr9
+            YyewbY8qZmOUGQ4xKlZmhojeMh/FEH8dGNEf1AxnKbuQdnW6lqGR/w==
+            -----END AGE ENCRYPTED FILE-----
+    lastmodified: "2024-03-31T16:01:00Z"
+    mac: ENC[AES256_GCM,data:AawTzIXyX+3FyFpw8pXFeVJJtXN7ZpTFnUqhedC2vcbbNUzMMt1X0SaxtNNJ5chZI/tYHn59FT6zznl1eO4Xn29Zc2Up4dkT1BE4yqkEG0hiCFXrXMz/PaHfROzBhIWCVyF4fYj6MZKg1iBBxhWRqhJlQ1q4UVkoaITRUKpFJgs=,iv:3lTPOQ8VjmP3WNGbFK2yLU4Ks1KviNS/l7TH4SnvSUs=,tag:KUbAU6+76/Uxj2Wn9EnqnA==,type:str]
+    pgp: []
+    unencrypted_suffix: _unencrypted
+    version: 3.8.1

nixos/machines/lobon/configuration.nix

@@ -0,0 +1,36 @@
+{
+  imports = [
+    ./hardware-configuration.nix
+    ../../modules/mailman.nix
+    ../../roles
+    ../../roles/vm.nix
+    ../../modules/vmNetwork.nix
+  ];
+
+  # System configuration here
+
+  services.mathebau-mailman = {
+    enable = true;
+    hostName = "lists.mathebau.de";
+    siteOwner = "root@mathebau.de";
+  };
+
+  networking.hostName = "lobon";
+  vmNetwork.ipv4 = "192.168.0.22";
+  system.stateVersion = "23.11";
+
+  sops.secrets = {
+    allowlistPass = {
+      sopsFile = ./allowlistPass.yaml;
+      owner = "mailman";
+      group = "mailman";
+      mode = "0400";
+    };
+    backupKey = {
+      sopsFile = ./backupKey.yaml;
+      owner = "root";
+      group = "root";
+      mode = "0400";
+    };
+  };
+}

nixos/machines/lobon/hardware-configuration.nix

@@ -0,0 +1,30 @@
+{
+  lib,
+  pkgs,
+  ...
+}: {
+  imports = [];
+
+  fileSystems."/" = {
+    device = "root";
+    fsType = "tmpfs";
+    options = ["size=1G" "mode=755"];
+  };
+  fileSystems."/persist" = {
+    device = "/dev/disk/by-label/nixos";
+    fsType = "btrfs";
+    options = ["subvol=persist"];
+    neededForBoot = true;
+  };
+  fileSystems."/boot" = {
+    device = "/dev/disk/by-label/boot";
+    fsType = "ext4";
+  };
+  fileSystems."/nix" = {
+    device = "/dev/disk/by-label/nixos";
+    fsType = "btrfs";
+    options = ["subvol=nix"];
+  };
+
+  nixpkgs.hostPlatform = lib.mkDefault "x86_64-linux";
+}

nixos/modules/borgbackup.nix

@@ -0,0 +1,165 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}: let
+  inherit
+    (lib)
+    mkIf
+    mkEnableOption
+    ;
+  cfg = config.services.mathebau-borgbackup;
+in {
+  imports = [];
+
+  options.services.mathebau-borgbackup = {
+    enable = mkEnableOption "mathebau borgbackup service";
+  };
+
+  config = mkIf cfg.enable {
+    services.borgbackup = {
+      # repos are made available at ssh://borg@hostname and served according to the presented ssh-key
+
+      # If you think about adding keys of nix machines:
+      # Congratulations, you are the first person to make backups from a nixos machine.
+      # Your won the task of automatizing this endeavor, so in future we don't need to hand copy any
+      # ssh keys anymore.
+      repos = {
+        aphoom-zhah = {
+          authorizedKeysAppendOnly = [
+            "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIA8pI6uinXezAMH4vG2yEbu/yOYU5vXcsZN74tYgV+Wj Aphoom-Zhah Backup"
+          ];
+          path = "/var/lib/backups/aphoom-zhah";
+          # subrepos are allowed because each vm creates at least one repo below this filepath and yibb-tstll even more
+          allowSubRepos = true;
+        };
+        azathoth = {
+          authorizedKeysAppendOnly = [
+            "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIGBEwllQ77ktoirXX6dJ6ET8TfK4lzq0aaq+X4rrX2Vk Azathoth Backup"
+          ];
+          path = "/var/lib/backups/azathoth";
+          allowSubRepos = true;
+        };
+        cthulhu = {
+          authorizedKeysAppendOnly = [
+            "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIMSJl1MvabUADTdOCgufsBzn1tIIpxMq4iDcYZsaW1lV Cthulhu Backup"
+          ];
+          path = "/var/lib/backups/cthulhu";
+          allowSubRepos = true;
+        };
+        eihort = {
+          authorizedKeysAppendOnly = [
+            "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIHLoDxtY4Tp6NKxLt9oHmWT6w4UpU6eA1TnPU2Ut83BN Eihort Backup"
+          ];
+          path = "/var/lib/backups/eihort";
+          allowSubRepos = true;
+        };
+        fsaccount = {
+          authorizedKeysAppendOnly = [
+            "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIG+Y7fQTYdIWHehrKdk92CaJ0AisEux4OrS4nIyMstU4 FS Account Backup"
+          ];
+          path = "/var/lib/backups/fsaccount";
+          allowSubRepos = true;
+        };
+        hastur = {
+          authorizedKeysAppendOnly = [
+            "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAILeDvTyOUdIPARatX0PPhHgrV1gjERWLt2Twa8E2GETb Hastur Backupsystem"
+          ];
+          path = "/var/lib/backups/hastur";
+          allowSubRepos = true;
+        };
+        ithaqua = {
+          authorizedKeysAppendOnly = [
+            "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIPJmBf8cz3FTDdeuxWbp1MO2yPT5rvH8ZIGUzfogjpXi Ithaqua Backup"
+          ];
+          path = "/var/lib/backups/ithaqua";
+          allowSubRepos = true;
+        };
+        lobon = {
+          authorizedKeysAppendOnly = [
+            "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAICEptjf1UWRlo6DG9alAIRwkSDUAVHwDKkHC6/DeYKzi Lobon Backup"
+          ];
+          path = "/var/lib/backups/lobon";
+          allowSubRepos = true;
+        };
+        sanctamariamaterdei = {
+          authorizedKeysAppendOnly = [
+            "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIH9Le5OI4ympQ0mQKYHmxgxGF598rzpD5VVpWK1mGfd8 Sanctamariamaterdei Backupsystem"
+          ];
+          path = "/var/lib/backups/sanctamariamaterdei";
+          allowSubRepos = true;
+        };
+        tsathoggua = {
+          authorizedKeysAppendOnly = [
+            "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIKS9/1lFOhv+3sNuGcysM3TYh2xRrjMeAZX3K7CBx0QW Tsathoggua Backup"
+          ];
+          path = "/var/lib/backups/tsathoggua";
+          allowSubRepos = true;
+        };
+        uvhash = {
+          authorizedKeysAppendOnly = [
+            "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIB8DjIqgFgmYhQnTLpbqL0r7xBPb8TPy6SO5RhQ31OGj Uvhash Backup"
+          ];
+          path = "/var/lib/backups/uvhash";
+          allowSubRepos = true;
+        };
+        yibb-tstll = {
+          authorizedKeysAppendOnly = [
+            "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAINlnGOV58Ks9lu+WTI4F7QAHtDrJq2jY8ZocITZG8K0+ Yibb-Tstll Backup"
+          ];
+          path = "/var/lib/backups/yibb-tstll";
+          allowSubRepos = true;
+        };
+      };
+      # Configure backup of files on the department's fs account:
+      # This job first copies the files to the local account 'fsaccount' in tmpfs
+      # and then takes a regular backup of the mirrored folder.
+
+      # See also https://borgbackup.readthedocs.io/en/stable/deployment/pull-backup.html
+      # which does not work due to missing permissions.
+      jobs.fsaccount = {
+        preHook = ''
+          mkdir -p /home/fsaccount/sicherung # Create if it does not exist
+          ${pkgs.rsync}/bin/rsync --rsh='ssh -i /run/secrets/backupKey' --recursive --delete fachschaft@gw1.mathematik.tu-darmstadt.de:/home/fachschaft/* /home/fsaccount/sicherung
+        '';
+        paths = "/home/fsaccount/sicherung";
+        encryption.mode = "none"; # Otherwise the key is next to the backup or we have human interaction.
+        environment = {
+          BORG_RSH = "ssh -i /run/secrets/backupKey";
+          # “Borg ensures that backups are not created on random drives that ‘just happen’ to contain a Borg repository.”
+          # https://borgbackup.readthedocs.io/en/stable/deployment/automated-local.html
+          # We don't want this in order to not need to persist borg cache and simplify new deployments.
+          BORG_UNKNOWN_UNENCRYPTED_REPO_ACCESS_IS_OK = "yes";
+        };
+        repo = "borg@localhost:fsaccount";
+        startAt = "daily";
+        user = "fsaccount";
+        group = "users";
+        readWritePaths = ["/home/fsaccount"];
+      };
+    };
+    # Extra user for FS account backup
+    users.users = {
+      fsaccount = {
+        description = "FS Account backup";
+        isSystemUser = true;
+        home = "/home/fsaccount";
+        createHome = true;
+        group = "users";
+      };
+    };
+    environment.persistence.${config.impermanence.name} = {
+      users.fsaccount.files = [
+        {
+          file = ".ssh/known_hosts";
+          parentDirectory = {
+            mode = "u=rwx,g=,o=";
+            user = "fsaccount";
+            group = "users";
+          };
+        }
+      ];
+    };
+  };
+}

nixos/modules/impermanence.nix

@@ -0,0 +1,47 @@
+{
+  lib,
+  config,
+  ...
+}: let
+  inherit
+    (lib)
+    mkEnableOption
+    mkIf
+    mkOption
+    types
+    ;
+  cfg = config.impermanence;
+in {
+  imports = [];
+
+  options.impermanence = {
+    enable = mkEnableOption "impermanence";
+    storagePath = mkOption {
+      type = types.path;
+      default = "/persist";
+      description = "The path where persistent data is stored";
+    };
+    name = mkOption {
+      type = types.str;
+      default = "persist";
+      description = "the name of the persistent data store";
+    };
+  };
+
+  config = mkIf cfg.enable {
+    environment.persistence.${cfg.name} = {
+      persistentStoragePath = cfg.storagePath;
+      directories = [
+        "/var/log"
+        "/var/lib/nixos"
+      ];
+      files = [
+        "/etc/ssh/ssh_host_ed25519_key"
+        "/etc/ssh/ssh_host_ed25519_key.pub"
+        "/etc/ssh/ssh_host_rsa_key"
+        "/etc/ssh/ssh_host_rsa_key.pub"
+      ];
+    };
+    environment.etc.machine-id.source = "${cfg.storagePath}/machine-id";
+  };
+}

nixos/modules/jitsi.nix

@@ -0,0 +1,61 @@
+{
+  config,
+  lib,
+  modulesPath,
+  ...
+}: let
+  inherit
+    (lib)
+    mkIf
+    mkEnableOption
+    mkOption
+    head
+    ;
+  inherit (lib.types) str;
+  cfg = config.services.mathebau-jitsi;
+in {
+  imports = [(modulesPath + "/services/web-apps/jitsi-meet.nix")];
+
+  options.services.mathebau-jitsi = {
+    enable = mkEnableOption "mathebau jitsi service";
+    hostName = mkOption {
+      type = str;
+    };
+    localAddress = mkOption {
+      type = str;
+      default = (head config.networking.interfaces.enX0.ipv4.addresses).address;
+    };
+  };
+
+  config = mkIf cfg.enable {
+    services = {
+      jitsi-meet = {
+        enable = true;
+        config = {
+          defaultLang = "de";
+        };
+        inherit (cfg) hostName;
+      };
+      jitsi-videobridge = {
+        openFirewall = true;
+        nat = {
+          publicAddress = "130.83.2.184";
+          inherit (cfg) localAddress;
+        };
+      };
+      #We are behind a reverse proxy that handles TLS
+      nginx.virtualHosts."${cfg.hostName}" = {
+        enableACME = false;
+        forceSSL = false;
+      };
+    };
+    environment.persistence.${config.impermanence.name} = {
+      directories = [
+        "/var/lib/jitsi-meet"
+        "/var/lib/prosody"
+      ];
+    };
+    #The network ports for HTTP(S) are not opened automatically
+    networking.firewall.allowedTCPPorts = [80 443];
+  };
+}

nixos/modules/mailman.nix

@@ -0,0 +1,128 @@
+# Adapted and simplified from https://nixos.wiki/wiki/Mailman
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}: let
+  inherit
+    (lib)
+    mkIf
+    mkEnableOption
+    mkOption
+    ;
+  inherit (lib.types) nonEmptyStr;
+  cfg = config.services.mathebau-mailman;
+in {
+  options.services.mathebau-mailman = {
+    enable = mkEnableOption "mathebau mailman service";
+    hostName = mkOption {
+      type = nonEmptyStr;
+    };
+    siteOwner = mkOption {
+      type = nonEmptyStr;
+    };
+  };
+
+  config = mkIf cfg.enable {
+    services = {
+      postfix = {
+        enable = true;
+        relayDomains = ["hash:/var/lib/mailman/data/postfix_domains"];
+        config = {
+          transport_maps = ["hash:/var/lib/mailman/data/postfix_lmtp"];
+          local_recipient_maps = ["hash:/var/lib/mailman/data/postfix_lmtp"];
+          proxy_interfaces = "130.83.2.184";
+          smtputf8_enable = "no"; # HRZ does not know SMTPUTF8
+        };
+        relayHost = "192.168.0.24"; # Relay to eihort which relays to HRZ (see https://www.hrz.tu-darmstadt.de/services/it_services/email_infrastruktur/index.de.jsp)
+      };
+      mailman = {
+        enable = true;
+        inherit (cfg) siteOwner;
+        hyperkitty.enable = true;
+        webHosts = [cfg.hostName];
+        serve.enable = true; #
+        # Don't include confirmation tokens in reply addresses, because we would need to send them to HRZ otherwise.
+        settings.mta.verp_confirmations = "no";
+      };
+    };
+
+    environment.persistence.${config.impermanence.name} = {
+      directories = [
+        "/var/lib/mailman"
+        "/var/lib/mailman-web"
+      ];
+      files = ["/root/.ssh/known_hosts"]; # for the backup server bragi
+    };
+
+    networking.firewall.allowedTCPPorts = [25 80];
+
+    # Update HRZ allowlist
+    # For account details see https://www-cgi.hrz.tu-darmstadt.de/mail/
+    # will stop working if no valid TUIDs are associated to our domain.
+    systemd.timers."mailAllowlist" = {
+      wantedBy = ["timers.target"];
+      timerConfig = {
+        OnBootSec = "5m"; # Run every 5 minutes
+        OnUnitActiveSec = "5m";
+        RandomizedDelaySec = "2m"; # prevent overload on regular intervals
+        Unit = "mailAllowlist.service";
+      };
+    };
+    systemd.services."mailAllowlist" = {
+      description = "Allowlist update: Post the mail addresses used by mailman to the HRZ allowllist";
+      script = ''
+        # Get the mail addresses' local-part
+        cut -d '@' -f 1 /var/lib/mailman/data/postfix_lmtp | grep -v '#' | grep "\S" > /tmp/addresses
+        # Post local-parts to HRZ
+        ${pkgs.curl}/bin/curl https://www-cgi.hrz.tu-darmstadt.de/mail/whitelist-update.php -F emaildomain=${cfg.hostName} -F password=$(cat /run/secrets/allowlistPass) -F emailliste=@/tmp/addresses -F meldungen=voll
+        # Cleanup
+        rm /tmp/addresses
+      '';
+      serviceConfig = {
+        Type = "oneshot";
+        User = "mailman";
+        NoNewPrivileges = true;
+        # See https://www.man7.org/linux/man-pages/man5/systemd.exec.5.html
+        PrivateTmp = true;
+        ProtectHome = true;
+        ReadOnlyPaths = "/";
+        ReadWritePaths = "/tmp";
+        InaccessiblePaths = "-/lost+found";
+        PrivateDevices = true;
+        PrivateUsers = true;
+        ProtectHostname = true;
+        ProtectClock = true;
+        ProtectKernelTunables = true;
+        ProtectKernelModules = true;
+        ProtectKernelLogs = true;
+        ProtectControlGroups = true;
+        LockPersonality = true;
+        MemoryDenyWriteExecute = true;
+        RestrictRealtime = true;
+        RestrictSUIDSGID = true;
+      };
+    };
+
+    # Backups
+    services.borgbackup.jobs.mailman = {
+      paths = [
+        "/var/lib/mailman/data"
+        "/var/lib/mailman-web"
+      ];
+      encryption.mode = "none"; # Otherwise the key is next to the backup or we have human interaction.
+      environment = {
+        BORG_RSH = "ssh -i /run/secrets/backupKey";
+        # “Borg ensures that backups are not created on random drives that ‘just happen’ to contain a Borg repository.”
+        # https://borgbackup.readthedocs.io/en/stable/deployment/automated-local.html
+        # We don't want this in order to not need to persist borg cache and simplify new deployments.
+        BORG_UNKNOWN_UNENCRYPTED_REPO_ACCESS_IS_OK = "yes";
+      };
+      repo = "borg@192.168.1.11:lobon"; # TODO for https://gitea.mathebau.de/Fachschaft/nixConfig/issues/33
+      startAt = "daily";
+      user = "root";
+      group = "root";
+    };
+  };
+}

nixos/modules/vmNetwork.nix

@@ -0,0 +1,48 @@
+{
+  lib,
+  config,
+  ...
+}: let
+  inherit
+    (lib)
+    mkOption
+    types
+    last
+    init
+    ;
+  inherit
+    (lib.strings)
+    splitString
+    concatStringsSep
+    toInt
+    ;
+  cfg = config.vmNetwork;
+in {
+  imports = [];
+
+  options.vmNetwork = {
+    ipv4 = mkOption {
+      type = types.str;
+      description = "the ipv4 adress of this machine";
+    };
+  };
+
+  config = {
+    networking = {
+      interfaces.enX0.ipv4.addresses = [
+        {
+          address = cfg.ipv4;
+          prefixLength = 16;
+        }
+      ];
+      defaultGateway = let
+        addr = splitString "." cfg.ipv4;
+        addrInit = init addr;
+        addrLastInt = builtins.toString (toInt (last addr) + 127);
+      in
+        concatStringsSep "." (addrInit ++ [addrLastInt]);
+      # https://www.hrz.tu-darmstadt.de/services/it_services/nameserver_dns/index.de.jsp
+      nameservers = ["130.83.22.63" "130.83.22.60" "130.83.56.60"];
+    };
+  };
+}

nixos/roles/admins.nix

@@ -0,0 +1,43 @@
+{lib, ...}:
+with lib; let
+  admins = {
+    nerf = {
+      hashedPassword = "$y$j9T$SJcjUIcs3JYuM5oyxfEQa/$tUBQT07FK4cb9xm.A6ZKVnFIPNOYMOKC6Dt6hadCuJ7";
+      sshKeys = [
+        "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIEdA4LpEGUUmN8esFyrNZXFb2GiBID9/S6zzhcnofQuP nerf@nerflap2"
+      ];
+      nixKeys = [
+        "nerflap2-1:pDZCg0oo9PxNQxwVSQSvycw7WXTl53PGvVeZWvxuqJc="
+      ];
+    };
+    gonne = {
+      hashedPassword = "$6$EtGpHEcFkOi0yUWp$slXf0CvIUrhdqaoCrQ5YwtYu2IVuE1RGGst4fnDPRLWVm.lYx0ruvSAF2/vw/sLbW37ORJjlb0NHQ.kSG7cVY/";
+      sshKeys = [
+        "sk-ssh-ed25519@openssh.com AAAAGnNrLXNzaC1lZDI1NTE5QG9wZW5zc2guY29tAAAAIAhwkSDISCWLN2GhHfxdZsVkK4J7JoEcPwtNbAesb+BZAAAABHNzaDo= Gonne"
+      ];
+      nixKeys = [
+        "gonne.mathebau.de-1:FsXFyFiBFE/JxC9MCkt/WuiXjx5dkRI9RXj0FxOQrV0="
+      ];
+    };
+  };
+
+  mkAdmin = name: {
+    hashedPassword,
+    sshKeys,
+    ...
+  }: {
+    "${name}" = {
+      isNormalUser = true;
+      createHome = true;
+      extraGroups = ["wheel"];
+      group = "users";
+      home = "/home/${name}";
+      openssh.authorizedKeys = {keys = sshKeys;};
+      inherit hashedPassword;
+    };
+  };
+  mkNixKeys = _: {nixKeys, ...}: nixKeys;
+in {
+  users.users = mkMerge (mapAttrsToList mkAdmin admins);
+  nix.settings.trusted-public-keys = lists.concatLists (mapAttrsToList mkNixKeys admins);
+}

nixos/roles/default.nix

@@ -1,4 +1,64 @@
-{ ... } : {
+{
+  pkgs,
+  lib,
+  ...
+}: {
+  imports = [
+    ./admins.nix
+    ./nix.nix
+    ./prometheusNodeExporter.nix
+    ../modules/impermanence.nix
+  ];
 
-sops.age.sshKeyPaths = [ "/etc/ssh/ssh_host_ed25519_key" ];
+  networking = {
+    firewall = {
+      # these shoud be default, but better make sure!
+      enable = true;
+      allowPing = true;
+    };
+    nftables.enable = true;
+    useDHCP = false; # We don't speak DHCP and even if we would, we should enable it per interface
+    # hosts = # TODO write something to autogenerate ip adresses!
+  };
+
+  users = {
+    mutableUsers = false;
+    users.root.hashedPassword = "!";
+  };
+
+  impermanence.enable = true;
+
+  sops.age.sshKeyPaths = ["/etc/ssh/ssh_host_ed25519_key"];
+
+  environment = {
+    systemPackages = builtins.attrValues {
+      inherit
+        (pkgs)
+        htop
+        lsof
+        tmux
+        btop
+        ;
+    };
+  };
+
+  services = {
+    journald.extraConfig = "SystemMaxUse=5G";
+
+    nginx = {
+      recommendedOptimisation = true;
+      recommendedGzipSettings = true;
+      recommendedTlsSettings = true;
+    };
+
+    openssh = {
+      enable = true;
+      settings = {
+        PermitRootLogin = "no";
+        PasswordAuthentication = false;
+      };
+    };
+    #Prevent clock drift due to interaction problem with xen hardware clock
+    timesyncd.enable = lib.mkForce true;
+  };
 }

nixos/roles/hardware.nix

@@ -0,0 +1,6 @@
+{
+  # Use grub as bootloader.
+  # Systemd-boot does not support our legacy BIOS hardware,
+  # but only runs on UEFI systems.
+  boot.loader.grub.enable = true;
+}

nixos/roles/nix.nix

@@ -0,0 +1,22 @@
+{
+  nix = {
+    settings = {
+      # trusted-public-keys belonging to specific persons are set in rolse/admins.nix
+      trusted-public-keys = [];
+      experimental-features = [
+        "flakes"
+        "nix-command"
+      ];
+      auto-optimise-store = true;
+      fallback = true;
+      builders-use-substitutes = true;
+    };
+    gc = {
+      automatic = true;
+      persistent = false;
+      dates = "weekly";
+      options = "-d";
+      randomizedDelaySec = "5h";
+    };
+  };
+}

nixos/roles/prometheusNodeExporter.nix

@@ -0,0 +1,39 @@
+{config, ...}: {
+  imports = [];
+  services.prometheus.exporters.node = {
+    enable = true;
+    port = 9100;
+    # Aligned with https://git.rwth-aachen.de/fsdmath/server/prometheus/-/blob/main/node_exporter/etc/default/prometheus-node-exporter
+    # It was compiled along the following steps:
+    # 1. Does the current Debian release supports the collector?
+    # 2. Is the collector depracated in the latest release?
+    # 3. Could you probably use the collected metrics for monitoring or are they useless because they make no sense in our context
+    #    (e.g. power adapter inside a VM, use fibre port connection)?
+    disabledCollectors = [
+      "arp"
+      "bcache"
+      "btrfs"
+      "dmi"
+      "fibrechannel"
+      "infiniband"
+      "nvme"
+      "powersupplyclass"
+      "rapl"
+      "selinux"
+      "tapestats"
+      "thermal_zone"
+      "udp_queues"
+      "xfs"
+      "zfs"
+    ];
+    enabledCollectors = [
+      "buddyinfo"
+      "ksmd"
+      "logind"
+      "mountstats"
+      "processes"
+    ];
+  };
+  networking.firewall.allowedTCPPorts = [9100];
+  environment.persistence.${config.impermanence.name}.directories = ["/var/lib/${config.services.prometheus.stateDir}"];
+}

nixos/roles/vm.nix

@@ -0,0 +1,5 @@
+{modulesPath, ...}: {
+  imports = [
+    (modulesPath + "/virtualisation/xen-domU.nix")
+  ];
+}