144 lines
5.2 KiB
Nix
144 lines
5.2 KiB
Nix
# 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;
|
||
};
|
||
}
|