diff --git a/artiq/master/worker_db.py b/artiq/master/worker_db.py
index 3ba176e09..950ec147f 100644
--- a/artiq/master/worker_db.py
+++ b/artiq/master/worker_db.py
@@ -22,8 +22,8 @@ def _create_device(desc, device_mgr):
         device_class = getattr(module, desc["class"])
         return device_class(device_mgr, **desc["arguments"])
     elif ty == "controller":
-        if desc["best_effort"]:
-            cl = BestEffortClient
+        if desc.get("best_effort", False):
+            cls = BestEffortClient
         else:
             cls = Client
         # Automatic target can be specified either by the absence of
diff --git a/examples/master/device_db.pyon b/examples/master/device_db.pyon
index effe4ef95..4e5618f3b 100644
--- a/examples/master/device_db.pyon
+++ b/examples/master/device_db.pyon
@@ -92,28 +92,24 @@
 
     "qc_q1_0": {
         "type": "controller",
-        "best_effort": false,
         "host": "::1",
         "port": 4000,
         "command": "pdq2_controller -p {port} --bind {bind} --simulation --dump qc_q1_0.bin"
     },
     "qc_q1_1": {
         "type": "controller",
-        "best_effort": false,
         "host": "::1",
         "port": 4001,
         "command": "pdq2_controller -p {port} --bind {bind} --simulation --dump qc_q1_1.bin"
     },
     "qc_q1_2": {
         "type": "controller",
-        "best_effort": false,
         "host": "::1",
         "port": 4002,
         "command": "pdq2_controller -p {port} --bind {bind} --simulation --dump qc_q1_2.bin"
     },
     "qc_q1_3": {
         "type": "controller",
-        "best_effort": false,
         "host": "::1",
         "port": 4003,
         "command": "pdq2_controller -p {port} --bind {bind} --simulation --dump qc_q1_3.bin"