fix(virtualisation): add & extend sub{u,g}id ranges

flake.nix

@@ -145,6 +145,7 @@ rec {
                 user.extraGroups = [ "wheel" "audio" "disk" "media" ];
                 modules = [ homeManagerModules.git ];
                 config = ./home/felschr.nix;
+                usesContainers = true;
               })
               ({ pkgs, ... }: {
                 environment.systemPackages =
@@ -168,6 +169,7 @@ rec {
                 user.extraGroups = [ "wheel" "audio" "disk" ];
                 modules = [ homeManagerModules.git ];
                 config = ./home/felschr-work.nix;
+                usesContainers = true;
               })
             ];
             specialArgs = { inherit inputs nixConfig; };

lib/createUser.nix

@@ -1,5 +1,5 @@
 name:
-{ user ? { }, hm ? { }, modules ? [ ], config, ... }:
+{ user ? { }, hm ? { }, modules ? [ ], config, usesContainers ? false, ... }:
 
 { pkgs, lib, home-manager, ... }: {
   imports = [ home-manager.nixosModules.home-manager ];
@@ -7,6 +7,16 @@ name:
   users.users."${name}" = {
     isNormalUser = true;
     shell = pkgs.zsh;
+
+    # increase sub{u,g}id range for container user namespaces
+    subUidRanges = lib.optionals usesContainers [{
+      startUid = 100000;
+      count = 60000000;
+    }];
+    subGidRanges = lib.optionals usesContainers [{
+      startGid = 100000;
+      count = 60000000;
+    }];
   } // user;
 
   home-manager = {

virtualisation/containers.nix

@@ -7,4 +7,27 @@ _:
     # Create unique User Namespace for the container
     containers.userns = "auto";
   };
+  virtualisation.containers.storage.settings = {
+    # defaults
+    storage = {
+      driver = "overlay";
+      graphroot = "/var/lib/containers/storage";
+      runroot = "/run/containers/storage";
+    };
+
+    # SUB_UID_MAX: https://man7.org/linux/man-pages/man5/login.defs.5.html
+    storage.options.auto-userns-max-size = 600100000;
+  };
+
+  # Increase sub{u,g}id range
+  users.users."root" = {
+    subUidRanges = [{
+      startUid = 60100000;
+      count = 60000000;
+    }];
+    subGidRanges = [{
+      startGid = 60100000;
+      count = 60000000;
+    }];
+  };
 }