nixpkgs/nixos/lib/make-disk-image.nix

120 lines
3.5 KiB
Nix

{ pkgs
, lib
, # The NixOS configuration to be installed onto the disk image.
config
, # The size of the disk, in megabytes.
diskSize
, # Whether the disk should be partitioned (with a single partition
# containing the root filesystem) or contain the root filesystem
# directly.
partitioned ? true
, # The root file system type.
fsType ? "ext4"
, # The initial NixOS configuration file to be copied to
# /etc/nixos/configuration.nix.
configFile ? null
, # Shell code executed after the VM has finished.
postVM ? ""
, name ? "nixos-disk-image"
, format ? "raw"
}:
with lib;
pkgs.vmTools.runInLinuxVM (
pkgs.runCommand name
{ preVM =
''
mkdir $out
diskImage=$out/nixos.${if format == "qcow2" then "qcow2" else "img"}
${pkgs.vmTools.qemu}/bin/qemu-img create -f ${format} $diskImage "${toString diskSize}M"
mv closure xchg/
'';
buildInputs = [ pkgs.utillinux pkgs.perl pkgs.e2fsprogs pkgs.parted ];
exportReferencesGraph =
[ "closure" config.system.build.toplevel ];
inherit postVM;
memSize = 1024;
}
''
${if partitioned then ''
# Create a single / partition.
parted /dev/vda mklabel msdos
parted /dev/vda -- mkpart primary ext2 1M -1s
. /sys/class/block/vda1/uevent
mknod /dev/vda1 b $MAJOR $MINOR
rootDisk=/dev/vda1
'' else ''
rootDisk=/dev/vda
''}
# Create an empty filesystem and mount it.
mkfs.${fsType} -L nixos $rootDisk
${optionalString (fsType == "ext4") ''
tune2fs -c 0 -i 0 $rootDisk
''}
mkdir /mnt
mount $rootDisk /mnt
# The initrd expects these directories to exist.
mkdir /mnt/dev /mnt/proc /mnt/sys
mount -o bind /proc /mnt/proc
mount -o bind /dev /mnt/dev
mount -o bind /sys /mnt/sys
# Copy all paths in the closure to the filesystem.
storePaths=$(perl ${pkgs.pathsFromGraph} /tmp/xchg/closure)
mkdir -p /mnt/nix/store
echo "copying everything (will take a while)..."
set -f
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.out}/bin/nix-store --load-db --option build-users-group ""
# Add missing size/hash fields to the database. FIXME:
# exportReferencesGraph should provide these directly.
chroot /mnt ${config.nix.package.out}/bin/nix-store --verify --check-contents
# Create the system profile to allow nixos-rebuild to work.
chroot /mnt ${config.nix.package.out}/bin/nix-env --option build-users-group "" \
-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
${optionalString (configFile != null) ''
cp ${configFile} /mnt/etc/nixos/configuration.nix
''}
# Generate the GRUB menu.
ln -s vda /dev/xvda
ln -s vda /dev/sda
chroot /mnt ${config.system.build.toplevel}/bin/switch-to-configuration boot
umount /mnt/proc /mnt/dev /mnt/sys
umount /mnt
# Do a fsck to make sure resize2fs works.
fsck.${fsType} -f -y $rootDisk
''
)