From 4d74ca100a1bcafb2f6ad74c017ec3c2448bf6ee Mon Sep 17 00:00:00 2001 From: Chandler Swift Date: Fri, 1 Nov 2024 01:36:31 -0500 Subject: [PATCH] Use DHCP for first stage boot This approach was recommended by nixos.wiki, and formerly by wiki.nixos.org, which has since switched to instead mentioning `boot.initrd.network.udhcpc.enable = true;`. It's not entirely clear to me which has an advantage over the other. This kernel parameter means that the kernel itself does the DHCP request, which is pretty neat! That seems to get set up in this file, though I haven't tracked down the exact details: https://github.com/torvalds/linux/blob/master/net/ipv4/ipconfig.c It seems like udhcpc may _also_ be enabled (since networking.useDHCP is set for the main system?), so maybe that could be disabled, but this appears to work so I'm rolling with it for the time being! Without the kernel param set, udhcpc tries and fails with errors like this: ``` <<< NixOS Stage 1 >>> loading module dm_mod... loading module af_packet... running udev... Starting systemd-udevd version 255.9 bringing up network interface eno1... acquiring IP address via DHCP on eno1... udhcpc: started, v1.36.1 udhcpc: broadcasting discover udhcpc: broadcasting discover udhcpc: broadcasting discover udhcpc: no lease, failing Passphrase for /dev/disk/by-uuid/00000000-0000-0000-0000-000000000000: _ ``` Compare with a working output: ``` <<< NixOS Stage 1 >>> loading module dm_mod... loading module af_packet... running udev... Starting systemd-udevd version 255.9 bringing up network interface eno1... acquiring IP address via DHCP on eno1... udhcpc: started, v1.36.1 udhcpc: broadcasting discover udhcpc: broadcasting discover udhcpc: broadcasting discover udhcpc: broadcasting select for 192.168.1.20, server 192.168.1.1 udhcpc: lease of 192.168.1.20 obtained from 192.168.1.1, lease time 43200 Passphrase for /dev/disk/by-uuid/00000000-0000-0000-0000-000000000000: _ ``` --- bert/configuration.nix | 1 + 1 file changed, 1 insertion(+) diff --git a/bert/configuration.nix b/bert/configuration.nix index 1e09172..5f46d8b 100644 --- a/bert/configuration.nix +++ b/bert/configuration.nix @@ -14,6 +14,7 @@ boot.loader.efi.canTouchEfiVariables = true; # Set up SSH unlocking + boot.kernelParams = [ "ip=dhcp" ]; boot.initrd = { availableKernelModules = [ "e1000e" ]; network = {