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Diffstat (limited to 'nixos/modules/virtualisation/amazon-image.nix')
| -rw-r--r-- | nixos/modules/virtualisation/amazon-image.nix | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/nixos/modules/virtualisation/amazon-image.nix b/nixos/modules/virtualisation/amazon-image.nix new file mode 100644 index 00000000000..7e04f0d2911 --- /dev/null +++ b/nixos/modules/virtualisation/amazon-image.nix @@ -0,0 +1,163 @@ +{ config, pkgs, ... }: + +with pkgs.lib; + +{ + imports = [ ../profiles/headless.nix ./ec2-data.nix ]; + + system.build.amazonImage = + pkgs.vmTools.runInLinuxVM ( + pkgs.runCommand "amazon-image" + { preVM = + '' + mkdir $out + diskImage=$out/nixos.img + ${pkgs.vmTools.qemu}/bin/qemu-img create -f raw $diskImage "4G" + mv closure xchg/ + ''; + buildInputs = [ pkgs.utillinux pkgs.perl ]; + exportReferencesGraph = + [ "closure" config.system.build.toplevel ]; + } + '' + # Create an empty filesystem and mount it. + ${pkgs.e2fsprogs}/sbin/mkfs.ext4 -L nixos /dev/vda + ${pkgs.e2fsprogs}/sbin/tune2fs -c 0 -i 0 /dev/vda + mkdir /mnt + mount /dev/vda /mnt + + # The initrd expects these directories to exist. + mkdir /mnt/dev /mnt/proc /mnt/sys + + mount -o bind /proc /mnt/proc + + # Copy all paths in the closure to the filesystem. + storePaths=$(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.environment.nix}/bin/nix-store --load-db + + # Create the system profile to allow nixos-rebuild to work. + chroot /mnt ${config.environment.nix}/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 + cp ${./amazon-config.nix} /mnt/etc/nixos/configuration.nix + + # Generate the GRUB menu. + chroot /mnt ${config.system.build.toplevel}/bin/switch-to-configuration boot + + umount /mnt/proc + umount /mnt + '' + ); + + fileSystems."/".device = "/dev/disk/by-label/nixos"; + + boot.initrd.kernelModules = [ "xen-blkfront" ]; + boot.kernelModules = [ "xen-netfront" ]; + + # Generate a GRUB menu. Amazon's pv-grub uses this to boot our kernel/initrd. + boot.loader.grub.version = 1; + boot.loader.grub.device = "nodev"; + boot.loader.grub.timeout = 0; + boot.loader.grub.extraPerEntryConfig = "root (hd0)"; + + boot.initrd.postDeviceCommands = + '' + # Force udev to exit to prevent random "Device or resource busy + # while trying to open /dev/xvda" errors from fsck. + udevadm control --exit || true + kill -9 -1 + ''; + + # Mount all formatted ephemeral disks and activate all swap devices. + # We cannot do this with the ‘fileSystems’ and ‘swapDevices’ options + # because the set of devices is dependent on the instance type + # (e.g. "m1.large" has one ephemeral filesystem and one swap device, + # while "m1.large" has two ephemeral filesystems and no swap + # devices). Also, put /tmp and /var on /disk0, since it has a lot + # more space than the root device. Similarly, "move" /nix to /disk0 + # by layering a unionfs-fuse mount on top of it so we have a lot more space for + # Nix operations. + boot.initrd.postMountCommands = + '' + diskNr=0 + diskForUnionfs= + for device in /dev/xvd[abcde]*; do + if [ "$device" = /dev/xvda -o "$device" = /dev/xvda1 ]; then continue; fi + fsType=$(blkid -o value -s TYPE "$device" || true) + if [ "$fsType" = swap ]; then + echo "activating swap device $device..." + swapon "$device" || true + elif [ "$fsType" = ext3 ]; then + mp="/disk$diskNr" + diskNr=$((diskNr + 1)) + echo "mounting $device on $mp..." + if mountFS "$device" "$mp" "" ext3; then + if [ -z "$diskForUnionfs" ]; then diskForUnionfs="$mp"; fi + fi + else + echo "skipping unknown device type $device" + fi + done + + if [ -n "$diskForUnionfs" ]; then + mkdir -m 755 -p $targetRoot/$diskForUnionfs/root + + mkdir -m 1777 -p $targetRoot/$diskForUnionfs/root/tmp $targetRoot/tmp + mount --bind $targetRoot/$diskForUnionfs/root/tmp $targetRoot/tmp + + if [ ! -e $targetRoot/.ebs ]; then + mkdir -m 755 -p $targetRoot/$diskForUnionfs/root/var $targetRoot/var + mount --bind $targetRoot/$diskForUnionfs/root/var $targetRoot/var + + mkdir -p /unionfs-chroot/ro-nix + mount --rbind $targetRoot/nix /unionfs-chroot/ro-nix + + mkdir -m 755 -p $targetRoot/$diskForUnionfs/root/nix + mkdir -p /unionfs-chroot/rw-nix + mount --rbind $targetRoot/$diskForUnionfs/root/nix /unionfs-chroot/rw-nix + + unionfs -o allow_other,cow,nonempty,chroot=/unionfs-chroot,max_files=32768 /rw-nix=RW:/ro-nix=RO $targetRoot/nix + fi + fi + ''; + + boot.initrd.extraUtilsCommands = + '' + # We need swapon in the initrd. + cp ${pkgs.utillinux}/sbin/swapon $out/bin + ''; + + # 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 EC2. + networking.hostName = mkDefault ""; + + # Always include cryptsetup so that Charon can use it. + environment.systemPackages = [ pkgs.cryptsetup ]; + + boot.initrd.supportedFilesystems = [ "unionfs-fuse" ]; +} |