diff --git a/python-service_identity.changes b/python-service_identity.changes
index c3d33ab..4e7c956 100644
--- a/python-service_identity.changes
+++ b/python-service_identity.changes
@@ -1,3 +1,9 @@
+-------------------------------------------------------------------
+Mon Oct  1 14:33:07 UTC 2018 - Bernhard Wiedemann <bwiedemann@suse.com>
+
+- Reduce parallelism of sphinx-build
+  to ensure reproducible builds (boo#1102408)
+
 -------------------------------------------------------------------
 Tue Sep 25 11:54:42 UTC 2018 - Tomáš Chvátal <tchvatal@suse.com>
 
diff --git a/python-service_identity.spec b/python-service_identity.spec
index b0c6594..b708acd 100644
--- a/python-service_identity.spec
+++ b/python-service_identity.spec
@@ -61,7 +61,9 @@ relevant RFCs too.
 
 # make man and documentation
 cd docs
-make %{?_smp_mflags} man singlehtml
+# do not run these in parallel to ensure reproducible builds (boo#1102408)
+make %{?_smp_mflags} man
+make %{?_smp_mflags} singlehtml
 
 %install
 %python_install