diff --git a/zuul/cmd/executor.py b/zuul/cmd/executor.py
index 5e5ea377d2..ba7426315d 100755
--- a/zuul/cmd/executor.py
+++ b/zuul/cmd/executor.py
@@ -86,7 +86,7 @@ class Executor(zuul.cmd.ZuulDaemonApp):
                     job_dir=self.job_dir))
                 sys.exit(1)
         else:
-            self.job_dir = tempfile.gettempdir()
+            self.job_dir = tempfile.mkdtemp()
 
         self.setup_logging('executor', 'log_config')
         self.log = logging.getLogger("zuul.Executor")
diff --git a/zuul/executor/server.py b/zuul/executor/server.py
index 237a70f41c..cac864803e 100644
--- a/zuul/executor/server.py
+++ b/zuul/executor/server.py
@@ -1897,6 +1897,15 @@ class ExecutorServer(object):
         with open(os.path.join(zuul_dir, '__init__.py'), 'w'):
             pass
 
+        # If keep is not set, ensure the job dir is empty on startup,
+        # in case we were uncleanly shut down.
+        if not self.keep_jobdir:
+            for fn in os.listdir(self.jobdir_root):
+                if not os.path.isdir(fn):
+                    continue
+                self.log.info("Deleting stale jobdir %s", fn)
+                shutil.rmtree(os.path.join(self.jobdir_root, fn))
+
         self.job_workers = {}
         self.disk_accountant = DiskAccountant(self.jobdir_root,
                                               self.disk_limit_per_job,