nix-community infrastructure

Welcome to the Nix Community infrastructure project. This project holds all the NixOS and Terraform configuration for this organization.

Community builder

We also provide one x86 hetzner build machine as a public remote builder for the nix community. If you want access read the security guide lines on aarch64-build-box. Than add your username to roles/builder/users.nix. Don't keep any important data in your home! We will regularly delete /home without further notice.

Using your NixOS home-manager configuration on the hosts

If you happen to have your NixOS & home-manager configurations intertwined but you'd like your familiar environment on our infrastructure you can evaluate pkgs.writeShellScript "hm-activate" config.systemd.services.home-manager-<yourusername>.serviceConfig.ExecStart from your NixOS configuration, and send this derivation to be realized remotely: (in case you aren't a Nix trusted user)

# somehow get the .drv of the above expression into $path
$ nix copy --to ssh://build01.nix-community.org --derivation $path
$ ssh build01.nix-community.org
$ nix-store -r $path
$ $path

(My implementation of this ~ckie)

Support

If you hit any issues, ping us on Matrix in the nix-community room (see the admin list below) or create an issue here: New Issue.

Administrators

• @adisbladis
• @flokli
• @grahamc
• @Mic92
• @nlewo
• @ryantm
• @zimbatm

Services

• BuildKite agent - on build01
• GitLab agent - on build01
• hound - on build01
• https://hydra.nix-community.org - on build01
• matterbridge - on build01
• ryantm-updater bot - on build02

Hosts

build01

This machine is perfect for running heavy builds.

• Provider: Hetzner
• CPU: AMD Ryzen 7 1700X Eight-Core Processor
• RAM: 64GB
• Drives: 2 x 512 GB SATA SSD

build02

This machine currently just runs r-ryantm/nixpkgs-update.

• Provider: Hetzner
• CPU: AMD Ryzen 7 3700X Eight-Core Processor
• RAM: 64GB DDR4 ECC
• Drives: 2 x 1 TB NVME in RAID 1

build03

This machine is a replacement for build01.

• Provider: Hetzner
• CPU: AMD Ryzen 5 3600 6-Core Processor
• RAM: 64GB DDR4 ECC
• Drives: 2 x 512 GB NVME in RAID 1

build04

This machine is meant as an aarch64 builder for our hydra instance running on build03.

• Provider: Oracle cloud
• Instance type: Ampere A1 Compute
• CPU: 4 VCPUs on an Ampere Altra (arm64)
• RAM: 24GB
• Drives: 200 GB Block

Cache

All the builds on these machines are pushed to https://nix-community.cachix.org/

Thanks to Cachix for sponsoring our binary cache!

File hierarchy

• ./build\d+ - build machines
• ./ci.sh - What is executed by CI
• ./deploy - Deploy script
• ./nix - pinned Nix dependencies and overlays
• ./roles - shared NixOS configuration modules
• ./secrets - git-crypt encrypted secrets
• ./services - single instances of NixOS services
• ./terraform - Setup DNS
• ./users - NixOS configuration of our admins

Deployment commands:

$ ./deploy

If you want to reboot a machine, use the following command to also deploy secrets afterwards:

$ inv deploy --hosts build02 reboot --hosts build02

Install/Fix system from Hetzner recovery mode

1. Install kexec image from Hetzner recovery system as described in kexec.nix and boot into it

2. Format and/or mount all filesystems to /mnt:

$ inv format-disks --hosts buildXX --disks /dev/nvme0n1,/dev/nvme1n1

3. Setup secrets

$ inv setup-secret --hosts buildXX

4. Generate configuration and download to the repo

$ nixos-generate-config  --root /tmp
# optional, in most cases one can import roles/hardware/hetzner-amd.nix
$ scp buildXX.nix-community.org:/tmp/etc/nixos/hardware-configuration.nix buildXX/hardware-configuration.nix

5. Build and install

$ inv install-nixos --hosts buildXX

Debug VM

You can start a vm from the rescue system in order to debug the boot:

$ nix-shell -p qemu_kvm --run 'qemu-kvm -m 10G -hda /dev/sda -hdb /dev/sdb -curses -cpu host -enable-kvm'