nix-community infrastructure

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

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
• marvin-mk2 - 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:

$ ./deploy --force-reboot --include build02

Install/Fix system from Hetzner recovery mode

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

# format disk with as follow:
# - partition 1 will be the boot partition, needed for legacy (BIOS) boot
# - partition 2 is for boot partition
# - partition 3 takes up the rest of the space and is for the system
$ sgdisk -n 1:2048:4095 -n 2:4096:+2G -N 3 -t 1:ef02 -t 2:8304 -t 3:8304 /dev/nvme0n1
$ sgdisk -n 1:2048:4095 -n 2:4096:+2G -N 3 -t 1:ef02 -t 2:8304 -t 3:8304 /dev/nvme1n1
# create mdadm raid for /boot with ext4
$ mdadm --create --verbose /dev/md127 --raid-devices=2 --level=1 /dev/nvme{0,1}n1p2
$ mkfs.ext4 -F /dev/md127
# format zpool
# use partuuids as they are more stable than device names
$ ls -la /dev/disk/by-partuuid/
$ zpool create zroot -O acltype=posixacl -O xattr=sa -O compression=lz4 mirror /dev/disk/by-partuuid/long-uuid1 /dev/disk/by-partuuid/long-uuid2
$ zpool create zroot -O acltype=posixacl -O xattr=sa -O compression=lz4 mirror /dev/nvme{0,1}n1p3
$ zfs create -o mountpoint=none zroot/root
$ zfs create -o mountpoint=legacy zroot/root/nixos
$ zfs create -o mountpoint=legacy zroot/root/home

# and finally mount
$ mount -t zfs zroot/root/nixos /mnt
$ mkdir /mnt/{home,boot}
$ mount -t zfs zroot/root/home /mnt/home
$ mount -t ext4 /dev/md127 /mnt/boot

2. Install kexec image from Hetzner recovery system as described in kexec.nix and boot into it
3. Download infra repo

$ nix-shell -p git --run "git clone https://github.com/nix-community/infra && cd infra && nix-shell"
# Just in case generate hardware-configuration.nix and compare it with what we have in the repos
$ nixos-generate-config  --root /mnt
$ diff -aur /mnt/etc/nixos/hardware-configuration.nix buildXX/hardware-configuration.nix

4. Build and install system

$ nixos-install --system $(nix-build -A buildXX-system)

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'