Files
lix/tests/nixos/containers/containers.nix
T
Raito Bezariusandeldritch horrors 9a59106c17 libstore: NIX_REMOTE=auto tries the daemon socket *then* direct access
In the past, it tried direct access if it *could* [1] perform direct
access.

This solves a bunch of errors people had when they tried the cgroup
feature and their scripts did not pass NIX_REMOTE=daemon manually
(nixos-rebuild-ng, home-manager activation from a root systemd unit,
etc.)

To avoid looping infinitely while receiving daemon connections, we
forcibly change the store URI when forking for a subdaemon to do direct
access automatically, this doesn't break forward usecases where you
point a daemon to another socket because we only change NIX_REMOTE="",
NIX_REMOTE=daemon, NIX_REMOTE=auto to a local and direct access.

All these usecases would end up infinitely looping no matter what
settings are set, because we are also responsible for creating the
daemon socket.

[1]: this happened all the time if you were `root`.

Related: https://github.com/NixOS/nixpkgs/pull/415701
Change-Id: I783fc795a9c2ee25b3d9f44f453f8f94b063371f
Signed-off-by: Raito Bezarius <raito@lix.systems>
2025-06-25 14:59:58 +00:00

76 lines
3.9 KiB
Nix

# Test whether we can run a NixOS container inside a Nix build using systemd-nspawn.
{ lib, nixpkgs, ... }:
{
name = "containers";
nodes =
{
host =
{ config, lib, pkgs, nodes, ... }:
{ virtualisation.writableStore = true;
virtualisation.diskSize = 2048;
virtualisation.additionalPaths =
[ pkgs.stdenvNoCC
(import ./systemd-nspawn.nix { inherit nixpkgs; }).toplevel
];
virtualisation.memorySize = 4096;
nix.settings = {
substituters = lib.mkForce [ ];
use-cgroups = true;
};
nix.extraOptions =
''
extra-experimental-features = nix-command auto-allocate-uids cgroups
extra-system-features = uid-range
'';
nix.nixPath = [ "nixpkgs=${nixpkgs}" ];
};
};
testScript = { nodes }: ''
start_all()
host.succeed("nix --version >&2")
# Test that 'id' gives the expected result in various configurations.
# Existing UIDs, sandbox.
host.succeed("nix build -v --no-auto-allocate-uids --no-use-cgroups --sandbox -L --offline --impure --file ${./id-test.nix} --argstr name id-test-1")
host.succeed("[[ $(cat ./result) = 'uid=1000(nixbld) gid=100(nixbld) groups=100(nixbld)' ]]")
# Existing UIDs, no sandbox.
host.succeed("nix build -v --no-auto-allocate-uids --no-use-cgroups --no-sandbox -L --offline --impure --file ${./id-test.nix} --argstr name id-test-2")
host.succeed("[[ $(cat ./result) = 'uid=30001(nixbld1) gid=30000(nixbld) groups=30000(nixbld)' ]]")
# Auto-allocated UIDs, sandbox but no cgroups.
host.fail("nix build -v --auto-allocate-uids --no-use-cgroups --sandbox -L --offline --impure --file ${./id-test.nix} --argstr name id-test-3")
# Auto-allocated UIDs, no sandbox but no cgroups.
host.fail("nix build -v --auto-allocate-uids --no-use-cgroups --no-sandbox -L --offline --impure --file ${./id-test.nix} --argstr name id-test-4")
# Auto-allocated UIDs, UID range, sandbox, via daemon.
host.succeed("nix build -v --auto-allocate-uids --sandbox -L --offline --impure --file ${./id-test.nix} --argstr name id-test-5 --arg uidRange true")
host.succeed("[[ $(cat ./result) = 'uid=0(root) gid=0(root) groups=0(root)' ]]")
# Auto-allocated UIDs, UID range, no sandbox, with and without daemon.
host.fail("nix build -v --auto-allocate-uids --no-sandbox -L --offline --impure --file ${./id-test.nix} --argstr name id-test-6 --arg uidRange true")
host.fail("nix build -v --auto-allocate-uids --no-use-cgroups --no-sandbox -L --offline --impure --file ${./id-test.nix} --argstr name id-test-7 --arg uidRange true")
# Run systemd-nspawn in a Nix build, via daemon.
host.succeed("nix build -vv --auto-allocate-uids --sandbox -L --offline --impure --file ${./systemd-nspawn.nix} --argstr nixpkgs ${nixpkgs}")
host.succeed("[[ $(cat ./result/msg) = 'Hello World' ]]")
# Auto-allocated UIDs, UID range, sandbox, WITHOUT daemon (so-called: Nix as root), IN `systemd-run` transient scope.
# `systemd-run` is CRITICAL to run this successfully.
host.succeed("systemd-run --same-dir --wait -E NIX_REMOTE=local -p Delegate=yes -p DelegateSubgroup=supervisor nix build -v --auto-allocate-uids --sandbox -L --offline --impure --file ${./id-test.nix} --argstr name id-test-8 --arg uidRange true -I nixpkgs=${nixpkgs}")
host.succeed("[[ $(cat ./result) = 'uid=0(root) gid=0(root) groups=0(root)' ]]")
# Run systemd-nspawn in a Nix build, WITHOUT daemon (so-called: Nix as root) IN `systemd-run`.
# `systemd-run` is CRITICAL to run this successfully.
host.succeed("systemd-run --same-dir --wait -E NIX_REMOTE=local -p Delegate=yes -p DelegateSubgroup=supervisor nix build -v --auto-allocate-uids --sandbox -L --offline --impure --file ${./systemd-nspawn.nix} --argstr nixpkgs ${nixpkgs} -I nixpkgs=${nixpkgs}")
host.succeed("[[ $(cat ./result/msg) = 'Hello World' ]]")
'';
}