From c0a49c95c128c7d2574e45da2ee8b1735b3d6238 Mon Sep 17 00:00:00 2001
From: atlas <atlas@hyperhive.local>
Date: Fri, 10 Jul 2026 14:20:04 +0200
Subject: [PATCH] fix(#2336): per-interface DHCP on eth0 instead of global
 useDHCP
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

nixos-containers.nix sets networking.useDHCP = false for every
container (to suppress the deprecated global DHCP warning). Setting
networking.useDHCP = true in the hive-ci inner config conflicts with
no priority differential → eval error on hosts running current main.

Fix: drop the global useDHCP = true and configure DHCP on eth0
(the inner veth interface name assigned by systemd-nspawn when
hostBridge is used). This is both conflict-free and the correct
modern NixOS practice for per-interface DHCP.
---
 nix/modules/hive-ci.nix | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/nix/modules/hive-ci.nix b/nix/modules/hive-ci.nix
index a2ed4e61..96ddebdb 100644
--- a/nix/modules/hive-ci.nix
+++ b/nix/modules/hive-ci.nix
@@ -410,11 +410,14 @@ in
           # affect traffic destined for the bridge IP itself.
           networking.nameservers = [ networkCfg.bridgeIp ];
           # With privateNetwork=true + hostBridge the container's veth
-          # is bridge-attached. Enable DHCP so the container gets an IP
-          # from dnsmasq on the bridge (hive-gateway serves the bridge
-          # subnet). Matches how normal hive agent containers acquire
-          # their addresses.
-          networking.useDHCP = true;
+          # is bridge-attached. Enable DHCP on eth0 so the container gets
+          # an IP from dnsmasq on the bridge (hive-gateway serves the
+          # bridge subnet). Per-interface rather than global: nixos-containers
+          # sets networking.useDHCP = false for all containers (to silence
+          # the deprecated global DHCP warning), so setting useDHCP = true
+          # globally would conflict. eth0 is the inner veth name assigned
+          # by systemd-nspawn when hostBridge is used.
+          networking.interfaces.eth0.useDHCP = true;
 
           # nspawn containers can't create user-namespaces, so nix
           # sandboxing always fails. Fall back to unsandboxed builds.