克隆构建器进程：使用 Nix（在 Linux 下）更新通道时不允许操作

Question

我使用 Arch Linux 4.19.15-1-lts #1 SMP Sun Jan 13 13:53:52 CET 2019 x86_64 GNU/Linux。我也安装了 Nix：nix-env (Nix) 2.2.

在最近更新到 version 之前，我从未遇到任何问题2.2。我总是通过以下两个步骤进行升级/更新：

$ nix-channel --update
...
$ nix-env --upgrade
...

...但在最近的2.2更新之后，我再也找不到nix-channel --update工作的方法了。我总是收到这些错误：

error: cloning builder process: Operation not permitted
error: unable to start build process
error: program '/nix/store/876x7a35qbn3q062b6zcz6va88m0990d-nix-2.2/bin/nix-env' failed with exit code 1

...即使我回滚以前的操作：

$ nix-channel --update 
unpacking channels...
error: cloning builder process: Operation not permitted
error: unable to start build process
error: program '/nix/store/876x7a35qbn3q062b6zcz6va88m0990d-nix-2.2/bin/nix-env' failed with exit code 1
$ nix-channel --rollback 
switching from generation 40 to 39
$ nix-channel --update 
unpacking channels...
error: cloning builder process: Operation not permitted
error: unable to start build process
error: program '/nix/store/876x7a35qbn3q062b6zcz6va88m0990d-nix-2.2/bin/nix-env' failed with exit code 1

这是我在更新列表中的内容：

$ nix-channel --list 
nixpkgs https://nixos.org/channels/nixpkgs-unstable

...最终我什至无法删除它：

$ nix-channel --remove nixpkgs 
uninstalling 'nixpkgs-19.03pre165281.7d864c6bd63'
error: cloning builder process: Operation not permitted
error: unable to start build process
error: program '/nix/store/876x7a35qbn3q062b6zcz6va88m0990d-nix-2.2/bin/nix-env' failed with exit code 1

我想避免重新安装。

---

更新

我等不及了！哦:)

我继续删除了当前的安装......当我重新安装时，我基本上得到了相同的结果：

$ sh <(curl https://nixos.org/nix/install) --no-daemon 
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  2476  100  2476    0     0   5417      0 --:--:-- --:--:-- --:--:--  5406
downloading Nix 2.2.1 binary tarball for x86_64-linux from 'https://nixos.org/releases/nix/nix-2.2.1/nix-2.2.1-x86_64-linux.tar.bz2' to '/tmp/nix-binary-tarball-unpack.n5vqvsi4Uq'...
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 22.5M  100 22.5M    0     0  4016k      0  0:00:05  0:00:05 --:--:-- 4377k
Note: a multi-user installation is possible. See https://nixos.org/nix/manual/#sect-multi-user-installation
performing a single-user installation of Nix...
directory /nix does not exist; creating it by running 'mkdir -m 0755 /nix && chown x80486 /nix' using sudo
[sudo] password for x80486: 
copying Nix to /nix/store.................................
initialising Nix database...
Nix: creating /home/x80486/.nix-profile
installing 'nix-2.2.1'
error: cloning builder process: Operation not permitted
error: unable to start build process
/tmp/nix-binary-tarball-unpack.n5vqvsi4Uq/unpack/nix-2.2.1-x86_64-linux/install: unable to install Nix into your default profile

...所以看起来，总的来说，Linux（或特别是使用的发行版）和 Nix 会发生一些事情。

Answer 1

按照此评论中的建议解决问题：

sysctl kernel.unprivileged_userns_clone=1