I am installing nixos onto an older dell poweredge r630. The box has two cpus and 28 cores in total. During the installation process, I get ‘all build users are currently in use …’. I added nix.nrBuildUsers = 100; and nix.maxJobs = 10; into the /mnt/nixos/configuration.nix with no change in behavior. I am not exactly sure what’s going on, so I could us some suggestions.
Managed to solve the problem with
nixos-install --max-jobs 1 --cores 1
Hi, did you manage to solve the problem since then?
I have the same problem:
[...] building '/nix/store/xkqnsfpk28pk8nqf4ck1hjalny71il5h-login.defs.drv'... error: all build users are currently in use; consider creating additional users and adding them to the 'nixbld' group
I also tried increasing
nix.maxJobs; to no avail.
trying to install from USB to a server:
[nixos@nixos:~]$ sudo inxi -M -S -z
System: Kernel: 5.4.84 x86_64 bits: 64 Console: tty 0 Distro: NixOS 20.09.2338.3d2d8f281a2 (Nightingale)
Machine: Type: Kvm System: Supermicro product: Super Server v: 0123456789 serial:
Mobo: Supermicro model: H11DSU-iN v: 2.10 serial:
<filter>UEFI: American Megatrends v: 2.1 date: 02/21/2020
On a 32 core server it also worked:
nixos-install --max-jobs 32 --cores 32
I ran into this too when installing on a HP Z820, also with 28 cores / 56 threads (dual E5-2680 v4). Interestingly, I don’t remember running into the same error when installing on a 64 core Dell R815 (quad Opteron 6380).
Looking at the configuration for a workaround I may have forgotten, I noticed back then
nixos-generate-config added a line like
nix.maxJobs = lib.mkDefault 64; to
hardware-configuration.nix, whereas on my new install it is absent and I have
max-jobs = auto in
It seems that change to
nixos-generate-config has led to insufficient build users being created, since the default is
nix.nrBuildUsers = mkDefault (lib.max 32 (if cfg.maxJobs == "auto" then 0 else cfg.maxJobs));
So, you found the right settings, but they won’t apply until after you switch to the new configuration, which requires specifying
-j in order for
nixos-install to succeed.
Ideally, I think
nix should be patched for
max-jobs = auto to take the number of build users into account…