nixpkgs/nixos/modules/virtualisation/google-compute-image.nix

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{ config, pkgs, ... }:
with pkgs.lib;
{
imports = [ ../profiles/headless.nix ../profiles/qemu-guest.nix ];
system.build.googleComputeImage =
pkgs.vmTools.runInLinuxVM (
pkgs.runCommand "google-compute-image"
{ preVM =
''
mkdir $out
diskImage=$out/disk.raw
truncate $diskImage --size 10G
mv closure xchg/
'';
postVM =
''
PATH=$PATH:${pkgs.gnutar}/bin:${pkgs.gzip}/bin
pushd $out
tar -Szcf disk.raw.tar.gz disk.raw
rm $out/disk.raw
popd
'';
buildInputs = [ pkgs.utillinux pkgs.perl ];
exportReferencesGraph =
[ "closure" config.system.build.toplevel ];
}
''
# Create partition table
${pkgs.parted}/sbin/parted /dev/vda mklabel msdos
${pkgs.parted}/sbin/parted /dev/vda mkpart primary ext4 1 10G
${pkgs.parted}/sbin/parted /dev/vda print
. /sys/class/block/vda1/uevent
mknod /dev/vda1 b $MAJOR $MINOR
# Create an empty filesystem and mount it.
${pkgs.e2fsprogs}/sbin/mkfs.ext4 -L nixos /dev/vda1
${pkgs.e2fsprogs}/sbin/tune2fs -c 0 -i 0 /dev/vda1
mkdir /mnt
mount /dev/vda1 /mnt
# The initrd expects these directories to exist.
mkdir /mnt/dev /mnt/proc /mnt/sys
mount --bind /proc /mnt/proc
mount --bind /dev /mnt/dev
mount --bind /sys /mnt/sys
# Copy all paths in the closure to the filesystem.
storePaths=$(perl ${pkgs.pathsFromGraph} /tmp/xchg/closure)
mkdir -p /mnt/nix/store
echo "copying everything (will take a while)..."
cp -prd $storePaths /mnt/nix/store/
# Register the paths in the Nix database.
printRegistration=1 perl ${pkgs.pathsFromGraph} /tmp/xchg/closure | \
chroot /mnt ${config.nix.package}/bin/nix-store --load-db
# Create the system profile to allow nixos-rebuild to work.
chroot /mnt ${config.nix.package}/bin/nix-env \
-p /nix/var/nix/profiles/system --set ${config.system.build.toplevel}
# `nixos-rebuild' requires an /etc/NIXOS.
mkdir -p /mnt/etc
touch /mnt/etc/NIXOS
# `switch-to-configuration' requires a /bin/sh
mkdir -p /mnt/bin
ln -s ${config.system.build.binsh}/bin/sh /mnt/bin/sh
# Install a configuration.nix.
mkdir -p /mnt/etc/nixos /mnt/boot/grub
cp ${./google-compute-config.nix} /mnt/etc/nixos/configuration.nix
# Generate the GRUB menu.
ln -s vda /dev/sda
chroot /mnt ${config.system.build.toplevel}/bin/switch-to-configuration boot
umount /mnt/proc /mnt/dev /mnt/sys
umount /mnt
''
);
fileSystems."/".label = "nixos";
boot.kernelParams = [ "console=ttyS0" "panic=1" "boot.panic_on_fail" ];
boot.initrd.kernelModules = [ "virtio_scsi" ];
# Generate a GRUB menu. Amazon's pv-grub uses this to boot our kernel/initrd.
boot.loader.grub.device = "/dev/sda";
boot.loader.grub.timeout = 0;
# Don't put old configurations in the GRUB menu. The user has no
# way to select them anyway.
boot.loader.grub.configurationLimit = 0;
# Allow root logins only using the SSH key that the user specified
# at instance creation time.
services.openssh.enable = true;
services.openssh.permitRootLogin = "without-password";
# Force getting the hostname from Google Compute.
networking.hostName = mkDefault "";
# Always include cryptsetup so that NixOps can use it.
environment.systemPackages = [ pkgs.cryptsetup ];
# Prevent logging in as root without a password. This doesn't really matter,
# since the only PAM services that allow logging in with a null
# password are local ones that are inaccessible on Google Compute machines.
security.initialRootPassword = "!";
# Configure default metadata hostnames
networking.extraHosts = ''
169.254.169.254 metadata.google.internal metadata
'';
# fetch authorized keys for root user
systemd.services.fetch-root-authorized-keys =
{ description = "Fetch authorized_keys for root user.";
wantedBy = [ "multi-user.target" ];
before = [ "sshd.service" ];
after = [ "network.target" ];
path = [ pkgs.curl ];
script =
''
# Don't download the SSH key if it has already been downloaded
if ! [ -e /root/.ssh/authorized_keys ]; then
echo "obtaining SSH key..."
mkdir -p /root/.ssh
curl -o /root/authorized-keys-metadata http://metadata/0.1/meta-data/authorized-keys
if [ $? -eq 0 -a -e /root/authorized-keys-metadata ]; then
cat /root/authorized-keys-metadata | cut -d: -f2- > /root/key.pub
if ! grep -q -f /root/key.pub /root/.ssh/authorized_keys; then
cat /root/key.pub >> /root/.ssh/authorized_keys
echo "new key added to authorized_keys"
fi
chmod 600 /root/.ssh/authorized_keys
rm -f /root/key.pub /root/authorized-keys-metadata
fi
fi
'';
serviceConfig.Type = "oneshot";
serviceConfig.RemainAfterExit = true;
};
}