diff --git a/nixos/release.nix b/nixos/release.nix
index 3307a3a6747..e782b0b7c63 100644
--- a/nixos/release.nix
+++ b/nixos/release.nix
@@ -132,6 +132,10 @@ in rec {
   manpages = buildFromConfig ({ pkgs, ... }: { }) (config: config.system.build.manual.manpages);
 
 
+  # Build the initial ramdisk so Hydra can keep track of its size over time.
+  initialRamdisk = buildFromConfig ({ pkgs, ... }: { }) (config: config.system.build.initialRamdisk);
+
+
   iso_minimal = forAllSystems (system: makeIso {
     module = ./modules/installer/cd-dvd/installation-cd-minimal.nix;
     type = "minimal";