From b0bce6ae731d5be0aed3277eab29d7ae7491d08d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jakub=20Oko=C5=84ski?= <jakub@okonski.org>
Date: Sat, 29 Oct 2022 22:22:43 +0200
Subject: [PATCH 1/2] maintainers: add farnoy

---
 maintainers/maintainer-list.nix | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/maintainers/maintainer-list.nix b/maintainers/maintainer-list.nix
index 3e5cefc356c..3e31fb0721c 100644
--- a/maintainers/maintainer-list.nix
+++ b/maintainers/maintainer-list.nix
@@ -4373,6 +4373,12 @@
     githubId = 1276854;
     name = "Florian Peter";
   };
+  farnoy = {
+    email = "jakub@okonski.org";
+    github = "farnoy";
+    githubId = 345808;
+    name = "Jakub Okoński";
+  };
   fbeffa = {
     email = "beffa@fbengineering.ch";
     github = "fedeinthemix";

From 12508ac79a3b940d42580e9cfb7d2037e7af3b00 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jakub=20Oko=C5=84ski?= <jakub@okonski.org>
Date: Sat, 29 Oct 2022 22:22:57 +0200
Subject: [PATCH 2/2] nixos-container: force systemd-nspawn to use unified
 cgroups hierarchy

---
 .../virtualisation/nixos-containers.nix       |  2 ++
 nixos/tests/all-tests.nix                     |  1 +
 nixos/tests/containers-unified-hierarchy.nix  | 21 +++++++++++++++++++
 .../nixos-container/default.nix               |  1 +
 4 files changed, 25 insertions(+)
 create mode 100644 nixos/tests/containers-unified-hierarchy.nix

diff --git a/nixos/modules/virtualisation/nixos-containers.nix b/nixos/modules/virtualisation/nixos-containers.nix
index 22be1d5bff9..4d51c53a604 100644
--- a/nixos/modules/virtualisation/nixos-containers.nix
+++ b/nixos/modules/virtualisation/nixos-containers.nix
@@ -138,6 +138,8 @@ let
         fi
       ''}
 
+      export SYSTEMD_NSPAWN_UNIFIED_HIERARCHY=1
+
       # Run systemd-nspawn without startup notification (we'll
       # wait for the container systemd to signal readiness)
       # Kill signal handling means systemd-nspawn will pass a system-halt signal
diff --git a/nixos/tests/all-tests.nix b/nixos/tests/all-tests.nix
index 47a433c0322..fe75f158290 100644
--- a/nixos/tests/all-tests.nix
+++ b/nixos/tests/all-tests.nix
@@ -143,6 +143,7 @@ in {
   containers-reloadable = handleTest ./containers-reloadable.nix {};
   containers-restart_networking = handleTest ./containers-restart_networking.nix {};
   containers-tmpfs = handleTest ./containers-tmpfs.nix {};
+  containers-unified-hierarchy = handleTest ./containers-unified-hierarchy.nix {};
   convos = handleTest ./convos.nix {};
   corerad = handleTest ./corerad.nix {};
   coturn = handleTest ./coturn.nix {};
diff --git a/nixos/tests/containers-unified-hierarchy.nix b/nixos/tests/containers-unified-hierarchy.nix
new file mode 100644
index 00000000000..978d59e12c8
--- /dev/null
+++ b/nixos/tests/containers-unified-hierarchy.nix
@@ -0,0 +1,21 @@
+import ./make-test-python.nix ({ pkgs, lib, ... }: {
+  name = "containers-unified-hierarchy";
+  meta = {
+    maintainers = with lib.maintainers; [ farnoy ];
+  };
+
+  nodes.machine = { ... }: {
+    containers = {
+      test-container = {
+        autoStart = true;
+        config = { };
+      };
+    };
+  };
+
+  testScript = ''
+    machine.wait_for_unit("default.target")
+
+    machine.succeed("echo 'stat -fc %T /sys/fs/cgroup/ | grep cgroup2fs' | nixos-container root-login test-container")
+  '';
+})
diff --git a/pkgs/tools/virtualization/nixos-container/default.nix b/pkgs/tools/virtualization/nixos-container/default.nix
index be17753b343..0b44bde4719 100644
--- a/pkgs/tools/virtualization/nixos-container/default.nix
+++ b/pkgs/tools/virtualization/nixos-container/default.nix
@@ -25,6 +25,7 @@ substituteAll {
           containers-ip
           containers-tmpfs
           containers-ephemeral
+          containers-unified-hierarchy
           ;
       };
     };