a527bb251a
We offer full cgroup delegation to our sandbox now, required for running containers inside the sandbox. To run systemd-nspawn or containers managers inside the sandbox, there is a need for one extra ingredient now: control over your own cgroup subtree inside the sandbox. If, in addition, you need multiple UIDs, for e.g. rootless usecases, you need to run with the `uid-range` system feature. Therefore, when the daemon or Nix runs under the right condition, e.g. systemd-style delegation of the cgroup subtree while placing the nix-daemon in a supervisor sub-cgroup, we create a new sub-cgroup for each build based on the build UID and delegate that sub-cgroup to the builder's process. Additionally, `uid-range` always request the `cgroups` feature now, as `uid-range` builds would probably always benefit from having cgroups delegated, but the converse is not true. Inspired from https://github.com/NixOS/nix/pull/11412 with a different design that does not use function-local statics to derive the root cgroup. Co-authored-by: Linus Heckemann <git@sphalerite.org> Co-authored-by: Parker Hoyes <contact@parkerhoyes.com> Change-Id: Ic8947c5adaf4b5bbd153386e05fad65a935274fa Signed-off-by: Raito Bezarius <raito@lix.systems>
41 lines
1.3 KiB
Nix
41 lines
1.3 KiB
Nix
{ nixpkgs, ... }:
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{
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name = "cgroups";
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nodes =
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{
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host =
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{ config, pkgs, ... }:
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{ virtualisation.additionalPaths = [ pkgs.stdenvNoCC ];
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nix.extraOptions =
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''
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extra-experimental-features = nix-command auto-allocate-uids cgroups
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extra-system-features = uid-range
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'';
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nix.settings.use-cgroups = true;
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nix.nixPath = [ "nixpkgs=${nixpkgs}" ];
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};
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};
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testScript = { nodes }: ''
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start_all()
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host.wait_for_unit("multi-user.target")
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# Start build in background
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host.execute("NIX_REMOTE=daemon nix build --use-cgroups --auto-allocate-uids --file ${./hang.nix} >&2 &")
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service = "/sys/fs/cgroup/system.slice/nix-daemon.service"
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# Wait for cgroups to be created
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host.succeed(f"until [ -e {service}/supervisor ]; do sleep 1; done", timeout=30)
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host.succeed(f"until [ -e {service}/nix-build-uid-* ]; do sleep 1; done", timeout=30)
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# Check that there aren't processes where there shouldn't be, and that there are where there should be
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host.succeed(f'[ -z "$(cat {service}/cgroup.procs)" ]')
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host.succeed(f'[ -n "$(cat {service}/supervisor/cgroup.procs)" ]')
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host.succeed(f'[ -n "$(cat {service}/nix-build-uid-*/cgroup.procs)" ]')
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'';
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}
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