{ config, lib, pkgs, ... }: with lib; let diskSize = "100G"; in { imports = [ ../profiles/headless.nix ../profiles/qemu-guest.nix ]; # https://cloud.google.com/compute/docs/tutorials/building-images networking.firewall.enable = mkDefault false; system.build.googleComputeImage = pkgs.vmTools.runInLinuxVM ( pkgs.runCommand "google-compute-image" { preVM = '' mkdir $out diskImage=$out/$diskImageBase truncate $diskImage --size ${diskSize} mv closure xchg/ ''; postVM = '' PATH=$PATH:${pkgs.gnutar}/bin:${pkgs.gzip}/bin pushd $out mv $diskImageBase disk.raw tar -Szcf $diskImageBase.tar.gz disk.raw rm $out/disk.raw popd ''; diskImageBase = "nixos-${config.system.nixosVersion}-${pkgs.stdenv.system}.raw"; 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 ${diskSize} ${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 --option build-users-group "" # 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} \ --option build-users-group "" # `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 ${config.system.build.toplevel}/bin/switch-to-configuration boot umount /mnt/proc /mnt/dev /mnt/sys umount /mnt '' ); fileSystems."/".label = "nixos"; boot.kernelParams = [ "console=ttyS0" "panic=1" "boot.panic_on_fail" ]; boot.initrd.kernelModules = [ "virtio_scsi" ]; boot.kernelModules = [ "virtio_pci" "virtio_net" ]; # Generate a GRUB menu. Amazon's pv-grub uses this to boot our kernel/initrd. boot.loader.grub.device = "/dev/sda"; boot.loader.grub.timeout = 0; # Don't put old configurations in the GRUB menu. The user has no # way to select them anyway. boot.loader.grub.configurationLimit = 0; # Allow root logins only using the SSH key that the user specified # at instance creation time. services.openssh.enable = true; services.openssh.permitRootLogin = "without-password"; services.openssh.passwordAuthentication = mkDefault false; # Force getting the hostname from Google Compute. networking.hostName = mkDefault ""; # Always include cryptsetup so that NixOps can use it. environment.systemPackages = [ pkgs.cryptsetup ]; # Configure default metadata hostnames networking.extraHosts = '' 169.254.169.254 metadata.google.internal metadata ''; services.ntp.servers = [ "metadata.google.internal" ]; networking.usePredictableInterfaceNames = false; systemd.services.fetch-ssh-keys = { description = "Fetch host keys and authorized_keys for root user"; wantedBy = [ "sshd.service" ]; before = [ "sshd.service" ]; after = [ "network-online.target" "ip-up.target" ]; wants = [ "network-online.target" "ip-up.target" ]; script = let wget = "${pkgs.wget}/bin/wget --retry-connrefused -t 15 --waitretry=10 --header='Metadata-Flavor: Google'"; in '' # When dealing with cryptographic keys, we want to keep things private. umask 077 # Don't download the SSH key if it has already been downloaded if ! [ -e /root/.ssh/authorized_keys ]; then echo "obtaining SSH key..." mkdir -m 0700 -p /root/.ssh ${wget} -O /root/authorized-keys-metadata http://metadata.google.internal/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 fi rm -f /root/key.pub /root/authorized-keys-metadata fi countKeys=0 ${flip concatMapStrings config.services.openssh.hostKeys (k : let kName = baseNameOf k.path; in '' echo "trying to obtain SSH private host key ${kName}" ${wget} -O /root/${kName} http://metadata.google.internal/0.1/meta-data/attributes/${kName} && : if [ $? -eq 0 -a -e /root/${kName} ]; then countKeys=$((countKeys+1)) mv -f /root/${kName} ${k.path} echo "downloaded ${k.path}" chmod 600 ${k.path} ${config.programs.ssh.package}/bin/ssh-keygen -y -f ${k.path} > ${k.path}.pub chmod 644 ${k.path}.pub fi rm -f /root/${kName} '' )} if [[ $countKeys -le 0 ]]; then echo "failed to obtain any SSH private host keys." false fi ''; serviceConfig.Type = "oneshot"; serviceConfig.RemainAfterExit = true; serviceConfig.StandardError = "journal+console"; serviceConfig.StandardOutput = "journal+console"; }; # Setings taken from https://cloud.google.com/compute/docs/tutorials/building-images#providedkernel boot.kernel.sysctl = { # enables syn flood protection "net.ipv4.tcp_syncookies" = mkDefault "1"; # ignores source-routed packets "net.ipv4.conf.all.accept_source_route" = mkDefault "0"; # ignores source-routed packets "net.ipv4.conf.default.accept_source_route" = mkDefault "0"; # ignores ICMP redirects "net.ipv4.conf.all.accept_redirects" = mkDefault "0"; # ignores ICMP redirects "net.ipv4.conf.default.accept_redirects" = mkDefault "0"; # ignores ICMP redirects from non-GW hosts "net.ipv4.conf.all.secure_redirects" = mkDefault "1"; # ignores ICMP redirects from non-GW hosts "net.ipv4.conf.default.secure_redirects" = mkDefault "1"; # don't allow traffic between networks or act as a router "net.ipv4.ip_forward" = mkDefault "0"; # don't allow traffic between networks or act as a router "net.ipv4.conf.all.send_redirects" = mkDefault "0"; # don't allow traffic between networks or act as a router "net.ipv4.conf.default.send_redirects" = mkDefault "0"; # reverse path filtering - IP spoofing protection "net.ipv4.conf.all.rp_filter" = mkDefault "1"; # reverse path filtering - IP spoofing protection "net.ipv4.conf.default.rp_filter" = mkDefault "1"; # ignores ICMP broadcasts to avoid participating in Smurf attacks "net.ipv4.icmp_echo_ignore_broadcasts" = mkDefault "1"; # ignores bad ICMP errors "net.ipv4.icmp_ignore_bogus_error_responses" = mkDefault "1"; # logs spoofed, source-routed, and redirect packets "net.ipv4.conf.all.log_martians" = mkDefault "1"; # log spoofed, source-routed, and redirect packets "net.ipv4.conf.default.log_martians" = mkDefault "1"; # implements RFC 1337 fix "net.ipv4.tcp_rfc1337" = mkDefault "1"; # randomizes addresses of mmap base, heap, stack and VDSO page "kernel.randomize_va_space" = mkDefault "2"; # provides protection from ToCToU races "fs.protected_hardlinks" = mkDefault "1"; # provides protection from ToCToU races "fs.protected_symlinks" = mkDefault "1"; # makes locating kernel addresses more difficult "kernel.kptr_restrict" = mkDefault "1"; # set ptrace protections "kernel.yama.ptrace_scope" = mkDefault "1"; # set perf only available to root "kernel.perf_event_paranoid" = mkDefault "2"; }; }