infrastructure/modules/dgn-runners/default.nix
2023-12-15 23:39:49 +01:00

331 lines
11 KiB
Nix

/* Copyright 2023 Clan contributers, Tom-Hubrecht
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to
deal in the Software without restriction, including without limitation the
rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
sell copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.
*/
{ config, pkgs, lib, ... }:
let
inherit (lib) mkEnableOption mkOption types;
storeDeps = pkgs.runCommand "store-deps" { } ''
mkdir -p $out/bin
for dir in ${builtins.toString cfg.dependencies}; do
for bin in "$dir"/bin/*; do
ln -s "$bin" "$out/bin/$(basename "$bin")"
done
done
# Add SSL CA certs
mkdir -p $out/etc/ssl/certs
cp -a "${pkgs.cacert}/etc/ssl/certs/ca-bundle.crt" $out/etc/ssl/certs/ca-bundle.crt
'';
cfg = config.dgn-runners;
storePaths = "nix-store --query -R ${builtins.toString (cfg.dependencies ++ [ pkgs.path ])}";
in {
options.dgn-runners = {
enable = mkEnableOption "Forgero Actions Runners.";
nbRunners = mkOption {
type = types.ints.positive;
default = 4;
};
storePath = mkOption {
type = types.str;
default = "/data/slow/nix";
};
dependencies = mkOption { type = with types; listOf package; };
};
config = lib.mkIf cfg.enable {
dgn-runners.dependencies = [
pkgs.bash
pkgs.colmena
pkgs.coreutils
pkgs.findutils
pkgs.gawk
pkgs.git
pkgs.gnugrep
pkgs.jq
pkgs.nix
pkgs.nodejs
pkgs.npins
pkgs.openssh
pkgs.tea
];
# everything here has no dependencies on the store
systemd.services = {
forgejo-nix-store = {
wantedBy = [ "multi-user.target" ];
path = [ pkgs.curl pkgs.nix ];
script = ''
dest=${cfg.storePath}
echo "[+] Performing an installation of Nix at $dest."
if ! [ -e "$dest" ]; then
echo "[+] Directory $dest does not exist, creating it."
mkdir -m 0755 $dest
fi
mkdir -p "$dest/store" "$dest/var/nix"
# Copy the required store paths
for i in $(${storePaths} | sed -e 's|/nix/store/||'); do
i_tmp="$dest/store/$i.$$"
if [ -e "$i_tmp" ]; then
rm -rf "$i_tmp"
fi
if ! [ -e "$dest/store/$i" ]; then
cp -RPp "/nix/store/$i" "$i_tmp"
chmod -R a-w "$i_tmp"
chmod +w "$i_tmp"
mv "$i_tmp" "$dest/store/$i"
chmod -w "$dest/store/$i"
fi
done
# Dump the corresponding db
nix-store --dump-db $(${storePaths}) | sed -e "s|/nix|$dest|" > .storeinfo
# Switch to the new store
export NIX_ROOT="$dest"
export NIX_STORE_DIR="$NIX_ROOT/store"
export NIX_DATA_DIR="$NIX_ROOT/share"
export NIX_STATE_DIR="$NIX_ROOT/var/nix"
nix-store --load-db < .storeinfo
# Setup the permissions to nixuser
chown -R nixuser:nixuser ${cfg.storePath}
'';
serviceConfig = {
RuntimeDirectory = "forgejo-store-nix";
WorkingDirectory = "/run/forgejo-store-nix";
Type = "oneshot";
RemainAfterExit = true;
};
};
forgejo-runner-nix-image = {
wantedBy = [ "multi-user.target" ];
after = [ "podman.service" "forgejo-nix-store.service" ];
requires = [ "podman.service" "forgejo-nix-store.service" ];
path = [
config.virtualisation.podman.package
pkgs.gnutar
pkgs.shadow
pkgs.getent
];
# we also include etc here because the cleanup job also wants the nixuser to be present
script = ''
set -eux -o pipefail
mkdir -p etc/nix
# Create an unpriveleged user that we can use also without the run-as-user.sh script
touch etc/passwd etc/group
groupid=$(cut -d: -f3 < <(getent group nixuser))
userid=$(cut -d: -f3 < <(getent passwd nixuser))
groupadd --prefix $(pwd) --gid "$groupid" nixuser
emptypassword='$6$1ero.LwbisiU.h3D$GGmnmECbPotJoPQ5eoSTD6tTjKnSWZcjHoVTkxFLZP17W9hRi/XkmCiAMOfWruUwy8gMjINrBMNODc7cYEo4K.'
useradd --prefix $(pwd) -p "$emptypassword" -m -d /tmp -u "$userid" -g "$groupid" -G nixuser nixuser
cat <<NIX_CONFIG > etc/nix/nix.conf
accept-flake-config = true
experimental-features = nix-command flakes
NIX_CONFIG
cat <<NSSWITCH > etc/nsswitch.conf
passwd: files mymachines systemd
group: files mymachines systemd
shadow: files
hosts: files mymachines dns myhostname
networks: files
ethers: files
services: files
protocols: files
rpc: files
NSSWITCH
# list the content as it will be imported into the container
tar -cv . | tar -tvf -
tar -cv . | podman import - forgejo-runner-nix
'';
serviceConfig = {
RuntimeDirectory = "forgejo-runner-nix-image";
WorkingDirectory = "/run/forgejo-runner-nix-image";
Type = "oneshot";
RemainAfterExit = true;
};
};
} // lib.genAttrs
(builtins.genList (n: "forgejo-runner-nix${builtins.toString n}")
cfg.nbRunners) (name: {
after = [ "forgejo-runner-nix-image.service" ];
requires = [ "forgejo-runner-nix-image.service" ];
# TODO: systemd confinment
serviceConfig = {
# Hardening (may overlap with DynamicUser=)
# The following options are only for optimizing output of systemd-analyze
AmbientCapabilities = "";
CapabilityBoundingSet = "";
# ProtectClock= adds DeviceAllow=char-rtc r
DeviceAllow = "";
NoNewPrivileges = true;
PrivateDevices = true;
PrivateMounts = true;
PrivateTmp = true;
PrivateUsers = true;
ProtectClock = true;
ProtectControlGroups = true;
ProtectHome = true;
ProtectHostname = true;
ProtectKernelLogs = true;
ProtectKernelModules = true;
ProtectKernelTunables = true;
ProtectSystem = "strict";
RemoveIPC = true;
RestrictNamespaces = true;
RestrictRealtime = true;
RestrictSUIDSGID = true;
UMask = "0066";
ProtectProc = "invisible";
SystemCallFilter = [
"~@clock"
"~@cpu-emulation"
"~@module"
"~@mount"
"~@obsolete"
"~@raw-io"
"~@reboot"
"~@swap"
# needed by go?
#"~@resources"
"~@privileged"
"~capset"
"~setdomainname"
"~sethostname"
];
RestrictAddressFamilies =
[ "AF_INET" "AF_INET6" "AF_UNIX" "AF_NETLINK" ];
# Needs network access
PrivateNetwork = false;
# Cannot be true due to Node
MemoryDenyWriteExecute = false;
# The more restrictive "pid" option makes `nix` commands in CI emit
# "GC Warning: Couldn't read /proc/stat"
# You may want to set this to "pid" if not using `nix` commands
ProcSubset = "all";
# Coverage programs for compiled code such as `cargo-tarpaulin` disable
# ASLR (address space layout randomization) which requires the
# `personality` syscall
# You may want to set this to `true` if not using coverage tooling on
# compiled code
LockPersonality = false;
# Note that this has some interactions with the User setting; so you may
# want to consult the systemd docs if using both.
DynamicUser = true;
};
});
users = {
users.nixuser = {
group = "nixuser";
description = "Used for running nix ci jobs";
home = "/var/empty";
isSystemUser = true;
};
groups.nixuser = { };
};
virtualisation = {
podman = {
enable = true;
defaultNetwork.settings = {
dns_enable = true;
ipv6_enabled = true;
};
};
containers.storage.settings = {
storage = {
driver = "overlay";
graphroot = "/data/slow/containers/storage";
runroot = "/run/containers/storage";
};
};
};
dgn-secrets.sources = [ ./. ];
services.gitea-actions-runner.instances = lib.genAttrs
(builtins.genList (n: "runner${builtins.toString n}") cfg.nbRunners)
(name: {
enable = true;
name = "nix-runner";
# take the git root url from the forgejo config
# only possible if you've also configured your forgejo though the same nix config
# otherwise you need to set it manually
url = "https://git.dgnum.eu";
# use your favourite nix secret manager to get a path for this
tokenFile = config.age.secrets."dgn_runners-token_file".path;
labels = [ "nix:docker://forgejo-runner-nix" ];
settings = {
container = {
options = builtins.toString [
"-e NIX_BUILD_SHELL=/bin/bash"
"-e PAGER=cat"
"-e PATH=/bin"
"-e NIX_PATH=nixpkgs=${builtins.toString pkgs.path}"
"--device /dev/kvm"
"-e SSL_CERT_FILE=/etc/ssl/certs/ca-bundle.crt"
"-v ${cfg.storePath}:/nix"
"-v ${storeDeps}/bin:/bin"
"-v ${storeDeps}/etc/ssl:/etc/ssl"
"--cpus=4"
"--device=/dev/kvm"
"--user nixuser"
];
# the default network that also respects our dns server settings
network = "host";
valid_volumes =
[ cfg.storePath "${storeDeps}/bin" "${storeDeps}/etc/ssl" ];
};
};
});
};
}