diff --git a/master/buildbot/db/masters.py b/master/buildbot/db/masters.py
index ed1ec706136..063570cea5f 100644
--- a/master/buildbot/db/masters.py
+++ b/master/buildbot/db/masters.py
@@ -91,6 +91,13 @@ def thd(conn):
                 for row in conn.execute(tbl.select()).fetchall()]
         return self.db.pool.do(thd)
 
+    def setAllMastersActiveLongTimeAgo(self, _reactor=reactor):
+        def thd(conn):
+            tbl = self.db.model.masters
+            q = tbl.update().values(active=1, last_active=0)
+            conn.execute(q)
+        return self.db.pool.do(thd)
+
     def _masterdictFromRow(self, row):
         return MasterDict(id=row.id, name=row.name,
                           active=bool(row.active),
diff --git a/master/buildbot/scripts/upgrade_master.py b/master/buildbot/scripts/upgrade_master.py
index 53995306c81..ff408834f48 100644
--- a/master/buildbot/scripts/upgrade_master.py
+++ b/master/buildbot/scripts/upgrade_master.py
@@ -157,6 +157,7 @@ def upgradeDatabase(config, master_cfg):
 
     yield db.setup(check_version=False, verbose=not config['quiet'])
     yield db.model.upgrade()
+    yield db.masters.setAllMastersActiveLongTimeAgo()
 
 
 @in_reactor
diff --git a/master/buildbot/test/unit/test_scripts_upgrade_master.py b/master/buildbot/test/unit/test_scripts_upgrade_master.py
index 89ad5eb3c74..b904a0adefb 100644
--- a/master/buildbot/test/unit/test_scripts_upgrade_master.py
+++ b/master/buildbot/test/unit/test_scripts_upgrade_master.py
@@ -20,6 +20,7 @@
 
 from buildbot import config as config_module
 from buildbot.db import connector
+from buildbot.db import masters
 from buildbot.db import model
 from buildbot.scripts import upgrade_master
 from buildbot.test.util import compat
@@ -274,6 +275,9 @@ def test_upgradeDatabase(self):
         self.patch(connector.DBConnector, 'setup', setup)
         upgrade = mock.Mock(side_effect=lambda **kwargs: defer.succeed(None))
         self.patch(model.Model, 'upgrade', upgrade)
+        setAllMastersActiveLongTimeAgo = mock.Mock(side_effect=lambda **kwargs: defer.succeed(None))
+        self.patch(masters.MastersConnectorComponent,
+                   'setAllMastersActiveLongTimeAgo', setAllMastersActiveLongTimeAgo)
         yield upgrade_master.upgradeDatabase(
             mkconfig(basedir='test', quiet=True),
             config_module.MasterConfig())
diff --git a/master/docs/developer/database.rst b/master/docs/developer/database.rst
index 1baf70b47c9..7a7c0003396 100644
--- a/master/docs/developer/database.rst
+++ b/master/docs/developer/database.rst
@@ -1413,6 +1413,12 @@ masters
         Get a list of the masters, represented as dictionaries; masters are sorted
         and paged using generic data query options
 
+    .. py:method:: setAllMastersActiveLongTimeAgo()
+
+        :returns: None via Deferred
+
+        This method is intended to be call by upgrade-master, and will effectively force housekeeping on all masters at next startup.
+        This method is not intended to be called outside of housekeeping scripts.
 
 builders
 ~~~~~~~~