diff --git a/flake.lock b/flake.lock
index 9800501..3c59156 100644
--- a/flake.lock
+++ b/flake.lock
@@ -16,9 +16,25 @@
         "type": "github"
       }
     },
+    "nixpkgs-master": {
+      "locked": {
+        "lastModified": 1629897889,
+        "narHash": "sha256-YoY/umk+NUtLFJgvTJkup6nLJb+sGEZ21hrupKTp7EI=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "6248814b6892af7dc0cf973b49690fd102088e02",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
     "root": {
       "inputs": {
         "nixpkgs": "nixpkgs",
+        "nixpkgs-master": "nixpkgs-master",
         "zentralwerk-network-key": "zentralwerk-network-key"
       }
     },
diff --git a/flake.nix b/flake.nix
index 7f1cbc8..18a84d2 100644
--- a/flake.nix
+++ b/flake.nix
@@ -3,12 +3,13 @@
 
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/release-21.05";
+    nixpkgs-master.url = "github:NixOS/nixpkgs";
     # `nix flake update --override-flake zentralwerk-network-key git+file:///...`
     # to provide the GPG secret key
     zentralwerk-network-key.url = "git+https://gitea.c3d2.de/zentralwerk/network.git?dir=nix/key";
   };
 
-  outputs = inputs@{ self, nixpkgs, zentralwerk-network-key }:
+  outputs = inputs@{ self, nixpkgs, nixpkgs-master, zentralwerk-network-key }:
     let
       system = "x86_64-linux";
       systems = [ system ];
@@ -22,6 +23,7 @@
           specialArgs.lib = self.lib;
           specialArgs.self = self;
           specialArgs.inputs = inputs;
+          specialArgs.nixpkgs-master = nixpkgs-master;
         };
     in {
       # Config, and utilities
diff --git a/nix/nixos-module/server/defaults.nix b/nix/nixos-module/server/defaults.nix
index f8a52ca..dac7030 100644
--- a/nix/nixos-module/server/defaults.nix
+++ b/nix/nixos-module/server/defaults.nix
@@ -1,4 +1,4 @@
-{ pkgs, ... }:
+{ pkgs, nixpkgs-master, ... }:
 {
   boot.kernelModules = [ "kvm-intel" "pppoe" ];
   boot.kernelParams = [ "nomodeset" ];
@@ -12,4 +12,11 @@
   ];
   services.openssh.enable = true;
   services.openssh.permitRootLogin = "prohibit-password";
+
+  # additional config for bare metal
+  services.collectd = {
+    plugins.ipmi = "";
+    # FIXME: IPMI is only available with nixpkgs-21.11 onwards
+    package = nixpkgs-master.legacyPackages.${pkgs.system}.collectd;
+  };
 }