nixpkgs/nixos/modules/virtualisation/amazon-image.nix
Antoine Eiche 933da6de91 nixos: Add ec2-metadata-fetcher.nix file
To share the metadata fetcher script between ec2 and Openstack images.
2019-02-11 20:58:45 +01:00

144 lines
5.2 KiB
Nix
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

# Configuration for Amazon EC2 instances. (Note that this file is a
# misnomer - it should be "amazon-config.nix" or so, not
# "amazon-image.nix", since it's used not only to build images but
# also to reconfigure instances. However, we can't rename it because
# existing "configuration.nix" files on EC2 instances refer to it.)
{ config, lib, pkgs, ... }:
with lib;
let
cfg = config.ec2;
metadataFetcher = import ./ec2-metadata-fetcher.nix {
targetRoot = "$targetRoot/";
wgetExtraOptions = "-q";
};
in
{
imports = [ ../profiles/headless.nix ./ec2-data.nix ./amazon-init.nix ];
config = {
assertions = [
{ assertion = cfg.hvm;
message = "Paravirtualized EC2 instances are no longer supported.";
}
];
boot.growPartition = cfg.hvm;
fileSystems."/" = {
device = "/dev/disk/by-label/nixos";
autoResize = true;
};
boot.extraModulePackages =
[ config.boot.kernelPackages.ixgbevf
config.boot.kernelPackages.ena
];
boot.initrd.kernelModules = [ "xen-blkfront" "xen-netfront" ];
boot.initrd.availableKernelModules = [ "ixgbevf" "ena" "nvme" ];
boot.kernelParams = mkIf cfg.hvm [ "console=ttyS0" ];
# Prevent the nouveau kernel module from being loaded, as it
# interferes with the nvidia/nvidia-uvm modules needed for CUDA.
# Also blacklist xen_fbfront to prevent a 30 second delay during
# boot.
boot.blacklistedKernelModules = [ "nouveau" "xen_fbfront" ];
# Generate a GRUB menu. Amazon's pv-grub uses this to boot our kernel/initrd.
boot.loader.grub.version = if cfg.hvm then 2 else 1;
boot.loader.grub.device = if cfg.hvm then "/dev/xvda" else "nodev";
boot.loader.grub.extraPerEntryConfig = mkIf (!cfg.hvm) "root (hd0)";
boot.loader.timeout = 0;
boot.initrd.network.enable = true;
# 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.small" 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 =
''
${metadataFetcher}
diskNr=0
diskForUnionfs=
for device in /dev/xvd[abcde]*; do
if [ "$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=$((diskNr + 1))
if mountFS "$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 $targetRoot/tmp
if [ "$(cat "$metaDir/ami-manifest-path")" != "(unknown)" ]; 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.
copy_bin_and_libs ${pkgs.utillinux}/sbin/swapon
'';
# 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 = "prohibit-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" ];
# EC2 has its own NTP server provided by the hypervisor
networking.timeServers = [ "169.254.169.123" ];
# udisks has become too bloated to have in a headless system
# (e.g. it depends on GTK+).
services.udisks2.enable = false;
};
}