Install NixOS on Oracle Cloud over Ubuntu 18.04 (make sure to use Ubuntu 18.04 or this may not work)
# install useful tools
sudo apt-get update
sudo apt-get install --no-install-recommends -y nano mc git
# prepare /boot
sudo umount /boot/efi
sudo mv /boot /boot.bak
sudo mkdir /boot/
sudo mount /dev/sda15 /boot
sudo mv /boot/* /boot.bak/efi/
# use swap file
sudo dd if=/dev/zero of=/swapfile bs=1M count=1024 status=progress
sudo chmod 600 /swapfile
sudo mkswap /swapfile
sudo swapon /swapfile
# install nix
sh <(curl -L https://nixos.org/nix/install)
. $HOME/.nix-profile/etc/profile.d/nix.sh
nix-channel --add https://nixos.org/channels/nixos-21.11 nixpkgs
nix-channel --update
# install nixos-generate-config and nixos-install
nix-env -f '<nixpkgs>' -iA nixos-install-tools
# generate config
sudo `which nixos-generate-config` --root /
# remove lxc mounts
sudo nano /etc/nixos/hardware-configuration.nix
# set hostname, add users and ssh-keys, enable openssh
sudo nano /etc/nixos/configuration.nix
# build config
nix-env -p /nix/var/nix/profiles/system -f '<nixpkgs/nixos>' -I nixos-config=/etc/nixos/configuration.nix -iA system
# prepare target
sudo chown -R 0.0 /nix
sudo touch /etc/NIXOS
sudo touch /etc/NIXOS_LUSTRATE
echo etc/nixos | sudo tee -a /etc/NIXOS_LUSTRATE
# install NixOS
sudo NIXOS_INSTALL_BOOTLOADER=1 /nix/var/nix/profiles/system/bin/switch-to-configuration boot
sudo reboot{
# Oracle Cloud uses EFI boot
boot.loader.systemd-boot.enable = true;
boot.loader.efi.canTouchEfiVariables = true;
# Kernel cmdline from Ubuntu config
boot.kernelParams = [
"console=ttyS0"
"console=tty1"
"nvme.shutdown_timeout=10"
"libiscsi.debug_libiscsi_eh=1"
];
# Load graphics driver in stage 1
boot.initrd.kernelModules = [ "bochs_drm" ];
# swap file is recommended
swapDevices = [
{
device = "/swapfile";
priority = 0;
}
];
}Create kexec.nix file with following contents (do not add any packages to environment.systemPackages or it won't boot on 1GB system):
{ config, pkgs, ... }:
{
imports = [
# this will work only under qemu, uncomment next line for full image
# <nixpkgs/nixos/modules/installer/netboot/netboot-minimal.nix>
<nixpkgs/nixos/modules/installer/netboot/netboot.nix>
<nixpkgs/nixos/modules/profiles/qemu-guest.nix>
];
# stripped down version of https://github.com/cleverca22/nix-tests/tree/master/kexec
system.build = rec {
image = pkgs.runCommand "image" { buildInputs = [ pkgs.nukeReferences ]; } ''
mkdir $out
cp ${config.system.build.kernel}/${config.system.boot.loader.kernelFile} $out/kernel
cp ${config.system.build.netbootRamdisk}/initrd $out/initrd
nuke-refs $out/kernel
'';
kexec_script = pkgs.writeTextFile {
executable = true;
name = "kexec-nixos";
text = ''
#!${pkgs.stdenv.shell}
set -e
${pkgs.kexectools}/bin/kexec -l ${image}/kernel --initrd=${image}/initrd --append="init=${builtins.unsafeDiscardStringContext config.system.build.toplevel}/init ${toString config.boot.kernelParams}"
sync
echo "executing kernel, filesystems will be improperly umounted"
${pkgs.kexectools}/bin/kexec -e
'';
};
kexec_tarball = pkgs.callPackage <nixpkgs/nixos/lib/make-system-tarball.nix> {
storeContents = [
{
object = config.system.build.kexec_script;
symlink = "/kexec_nixos";
}
];
contents = [ ];
compressCommand = "cat";
compressionExtension = "";
};
kexec_tarball_self_extract_script = pkgs.writeTextFile {
executable = true;
name = "kexec-nixos";
text = ''
#!/bin/sh
set -eu
ARCHIVE=`awk '/^__ARCHIVE_BELOW__/ { print NR + 1; exit 0; }' $0`
tail -n+$ARCHIVE $0 | tar x -C /
/kexec_nixos $@
exit 1
__ARCHIVE_BELOW__
'';
};
kexec_bundle = pkgs.runCommand "kexec_bundle" { } ''
cat \
${kexec_tarball_self_extract_script} \
${kexec_tarball}/tarball/nixos-system-${kexec_tarball.system}.tar \
> $out
chmod +x $out
'';
};
boot.initrd.availableKernelModules = [ "ata_piix" "uhci_hcd" ];
boot.kernelParams = [
"panic=30" "boot.panic_on_fail" # reboot the machine upon fatal boot issues
"console=ttyS0" # enable serial console
"console=tty1"
];
boot.kernel.sysctl."vm.overcommit_memory" = "1";
environment.systemPackages = with pkgs; [ cryptsetup ];
environment.variables.GC_INITIAL_HEAP_SIZE = "1M";
networking.hostName = "kexec";
services.getty.autologinUser = "root";
services.openssh = {
enable = true;
challengeResponseAuthentication = false;
passwordAuthentication = false;
};
documentation.enable = false;
documentation.nixos.enable = false;
fonts.fontconfig.enable = false;
programs.bash.enableCompletion = false;
programs.command-not-found.enable = false;
security.polkit.enable = false;
security.rtkit.enable = pkgs.lib.mkForce false;
services.udisks2.enable = false;
i18n.supportedLocales = [ (config.i18n.defaultLocale + "/UTF-8") ];
users.users.root.openssh.authorizedKeys.keys = [
# add your ssh key here
"ssh-ed25519 ...."
];
}Build kexec image (you'll need nix/NixOS installed on your machine):
nix-build '<nixpkgs/nixos>' -A config.system.build.kexec_bundle -I nixos-config=./kexec.nixCopy tarball to remote machine using scp and reboot into kexec image:
scp ./result ubuntu@somehost:/tmp/kexec
ssh ubuntu@somehost -t sudo /tmp/kexec
# wait for machine to boot and then connect
ssh root@somehostRepartition your drive, format, mount file systems, create swap(file) and activate it as soon as possible. Check manual for more info.
I'd recommend to install the minimal system without flakes like described in the document and then convert the system to flakes.
If you want to repartition the disk there's https://github.com/nix-community/nixos-images#kexec-tarballs
I've used it recently to install NixOS with ZFS on a 1GB free tier instance, but I had to eval and build the system closure elsewhere.