diff --git a/build/BUILD.bazel b/build/BUILD.bazel
new file mode 100644
index 0000000..20cfd57
--- /dev/null
+++ b/build/BUILD.bazel
@@ -0,0 +1,17 @@
+load("//build/filter_stamp:def.bzl", "filtered_stamp")
+
+# This is a filtered stable status file which contains only the variables which
+# do not change on every commit. Using this instead of the status file avoids
+# unnecessary rebuilds.
+filtered_stamp(
+    name = "stabler_status",
+    vars = [
+        "KUBERNETES_gitMajor",
+        "KUBERNETES_gitMinor",
+        "KUBERNETES_gitVersion",
+        "KUBERNETES_gitCommit",
+        "KUBERNETES_gitTreeState",
+        "KUBERNETES_buildDate",
+    ],
+    visibility = ["//visibility:public"],
+)
diff --git a/build/print-workspace-status.py b/build/print-workspace-status.py
index 9eb551f..d54333d 100755
--- a/build/print-workspace-status.py
+++ b/build/print-workspace-status.py
@@ -21,11 +21,8 @@
 #    only within the context of some product.
 
 from dataclasses import dataclass
-from datetime import datetime, timezone
-import os
 import re
 import subprocess
-import time
 
 from typing import Optional
 
@@ -45,18 +42,17 @@
     subprocess.check_output(["git", "rev-parse", "HEAD^{commit}"]).decode().strip()
 )
 
+# Git commit date.
+git_commit_date: str = (
+    subprocess.check_output(["git", "show", "--pretty=format:%cI", "--no-patch", "HEAD"]).decode().strip()
+)
+
 # Git tags pointing at this commit.
 git_tags_b: [bytes] = subprocess.check_output(
     ["git", "tag", "--sort=-version:refname", "--points-at", "HEAD"]
 ).split(b"\n")
 git_tags: [str] = [t.decode().strip() for t in git_tags_b if t.decode().strip() != ""]
 
-# Build timestamp, respecting SOURCE_DATE_EPOCH for reproducible builds.
-build_timestamp = int(time.time())
-sde = os.environ.get("SOURCE_DATE_EPOCH")
-if sde is not None:
-    build_timestamp = int(sde)
-
 variables["STABLE_MONOGON_gitCommit"] = git_commit
 variables["STABLE_MONOGON_gitTreeState"] = git_tree_state
 
@@ -94,6 +90,10 @@
     return Version(product, version, [])
 
 
+# Is this a release build of the given product?
+is_release: dict[str, bool] = {}
+
+
 for product in ["metropolis", "cloud"]:
     # Get exact version from tags.
     version = None
@@ -102,6 +102,8 @@
         if version is not None:
             break
 
+    is_release[product] = version is not None and git_tree_state == "clean"
+
     if version is None:
         # No exact version found. Use latest tag for the given product and
         # append a 'devXXX' identifier based on number of commits since that
@@ -193,16 +195,17 @@
 if not kubernetes_version_parsed:
     raise Exception("invalid Kubernetes version: " + kubernetes_version)
 
-# The Kubernetes build tree is considered clean iff the monorepo build tree is
-# considered clean.
-variables["KUBERNETES_gitTreeState"] = git_tree_state
-variables["KUBERNETES_buildDate"] = datetime.fromtimestamp(
-    build_timestamp, timezone.utc
-).strftime("%Y-%m-%dT%H:%M:%SZ")
 variables["STABLE_KUBERNETES_gitMajor"] = kubernetes_version_parsed[1]
 variables["STABLE_KUBERNETES_gitMinor"] = kubernetes_version_parsed[2]
 variables["STABLE_KUBERNETES_gitVersion"] = kubernetes_version + "+mngn"
 
+# Stamp commit info into Kubernetes only for release builds, to avoid
+# unnecessary rebuilds of hyperkube during development.
+if is_release["metropolis"]:
+    variables["STABLE_KUBERNETES_gitCommit"] = git_commit
+    variables["STABLE_KUBERNETES_gitTreeState"] = git_tree_state
+    variables["STABLE_KUBERNETES_buildDate"] = git_commit_date
+
 # Emit variables to stdout for consumption by Bazel and targets.
 for key in sorted(variables.keys()):
     print("{} {}".format(key, variables[key]))
diff --git a/metropolis/node/kubernetes/hyperkube/BUILD.bazel b/metropolis/node/kubernetes/hyperkube/BUILD.bazel
index 9fb4c22..3930eb8 100644
--- a/metropolis/node/kubernetes/hyperkube/BUILD.bazel
+++ b/metropolis/node/kubernetes/hyperkube/BUILD.bazel
@@ -1,5 +1,4 @@
 load("@io_bazel_rules_go//go:def.bzl", "go_binary", "go_library")
-load(":kubernetes_version_def.bzl", "version_x_defs")
 
 go_library(
     name = "hyperkube_lib",
@@ -18,9 +17,24 @@
     ],
 )
 
+stamp_pkgs = [
+    "k8s.io/component-base/version",
+    "k8s.io/client-go/pkg/version",
+]
+
+stamp_vars = [
+    "gitMajor",
+    "gitMinor",
+    "gitVersion",
+    "gitCommit",
+    "gitTreeState",
+    "buildDate",
+]
+
 go_binary(
     name = "hyperkube",
     embed = [":hyperkube_lib"],
+    stampsrcs = ["//build:stabler_status"],
     visibility = ["//metropolis/node:__pkg__"],
-    x_defs = version_x_defs(),
+    x_defs = {"%s.%s" % (pkg, var): "{STABLER_KUBERNETES_%s}" % var for pkg in stamp_pkgs for var in stamp_vars},
 )
diff --git a/metropolis/node/kubernetes/hyperkube/kubernetes_version_def.bzl b/metropolis/node/kubernetes/hyperkube/kubernetes_version_def.bzl
deleted file mode 100644
index ddd1347..0000000
--- a/metropolis/node/kubernetes/hyperkube/kubernetes_version_def.bzl
+++ /dev/null
@@ -1,48 +0,0 @@
-#  Copyright 2020 The Monogon Project Authors.
-#
-#  SPDX-License-Identifier: Apache-2.0
-#
-#  Licensed under the Apache License, Version 2.0 (the "License");
-#  you may not use this file except in compliance with the License.
-#  You may obtain a copy of the License at
-#
-#      http://www.apache.org/licenses/LICENSE-2.0
-#
-#  Unless required by applicable law or agreed to in writing, software
-#  distributed under the License is distributed on an "AS IS" BASIS,
-#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-#  See the License for the specific language governing permissions and
-#  limitations under the License.
-
-# This reimplements k8s.io/kubernetes-compatible version_x_defs, while namespacing
-# stamp variables with KUBERNETES_*.
-# The generated build defs then are defines by the workspace status script, see
-# //build/print-workspace-status.sh.
-
-def version_x_defs():
-    stamp_pkgs = [
-        "k8s.io/component-base/version",
-        "k8s.io/client-go/pkg/version",
-    ]
-
-    stamp_vars = [
-        "buildDate",
-        "gitCommit",
-        "gitTreeState",
-    ]
-
-    stable_stamp_vars = [
-        "gitMajor",
-        "gitMinor",
-        "gitVersion",
-    ]
-
-    # Generate the cross-product.
-    x_defs = {}
-    for pkg in stamp_pkgs:
-        for var in stamp_vars:
-            x_defs["%s.%s" % (pkg, var)] = "{KUBERNETES_%s}" % var
-    for pkg in stamp_pkgs:
-        for var in stable_stamp_vars:
-            x_defs["%s.%s" % (pkg, var)] = "{STABLE_KUBERNETES_%s}" % var
-    return x_defs