[GPLv3+] install nixos over the existing OS in a DigitalOcean droplet (and others with minor modifications)
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Danylo Hlynskyi 1f8634dd48 more robust removeSwap
During my nixos-infect tests I have sometimes canceled infection in the middle.
Rerun of nixos-infect failed because there were some old swap files, which
were no longer available as swap devices.

`swapoff -a` will handle this for us (we are going reboot anyway)
2018-07-12 15:04:17 -07:00
nixos-infect more robust removeSwap 2018-07-12 15:04:17 -07:00
README.md suggest 18.03 in readme to match config gen 2018-04-04 08:02:22 -07:00

This script aims to install NixOS on Digital Ocean droplets (starting from one of the distros that Digital Ocean supports out of the box)

These are the only supported Digital Ocean images:

  • Fedora 24 x64
  • Ubuntu 16.04 x64

It has also been successfully tested on OVH Virtual Private Servers (with debian)

YMMV with any other hoster + image combination.

nixos-infect is so named because of the high likelihood of rendering a system inoperable. Use with caution and preferably only on newly-provisioned systems.

WARNING NB: This script wipes out the targeted host's root filesystem when it runs to completion. Any errors halt execution. It's advised to run with bash -x to help debug, as often a failed run leaves the system in an inconsistent state, requiring a rebuild (in DigitalOcean panel: Droplet Settings -> "Destroy" -> "Rebuild from original").

TO USE:

  • Add any custom config you want (see notes below)
  • Deploy the droplet indicated at the top of the file, enable ipv6, add your ssh key
  • cat customConfig.optional nixos-infect | ssh root@targethost

Alternatively, use the user data mechamism by supplying the lines between the following cat and EOF in the Digital Ocean Web UI (or HTTP API):

#cloud-config

runcmd:
  - curl https://raw.githubusercontent.com/elitak/nixos-infect/master/nixos-infect | NIX_CHANNEL=nixos-18.03 bash 2>&1 | tee /tmp/infect.log

Potential tweaks:

  • /etc/nixos/{,hardware-}configuration.nix: rudimentary mostly static config
  • /etc/nixos/networking.nix, networking settings determined at runtime tweak if no ipv6, different number of adapters, etc.
#cloud-config
write_files:
- path: /etc/nixos/host.nix
  permissions: '0644'
  content: |
    {pkgs, ...}:
    {
      environment.systemPackages = with pkgs; [ vim ];
    }    
runcmd:
  - curl https://raw.githubusercontent.com/elitak/nixos-infect/master/nixos-infect | NIXOS_IMPORT=./host.nix NIX_CHANNEL=nixos-18.03 bash 2>&1 | tee /tmp/infect.log

Motivation for this script: nixos-assimilate should supplant this script entirely, if it's ever completed. nixos-in-place was quite broken when I tried it, and also took a pretty janky approach that was substantially more complex than this (although it supported more platforms): it didn't install to root (/nixos instead), left dregs of the old filesystem (almost always unnecessary since starting from a fresh deployment), and most importantly, simply didn't work for me! (old system was being because grub wasnt properly reinstalled)