diff --git a/oslo_messaging/_drivers/matchmaker_redis.py b/oslo_messaging/_drivers/matchmaker_redis.py
index f77b755cf..4ba5447c5 100644
--- a/oslo_messaging/_drivers/matchmaker_redis.py
+++ b/oslo_messaging/_drivers/matchmaker_redis.py
@@ -128,7 +128,7 @@ class MatchMakerRedis(mm_common.HeartbeatMatchMakerBase):
             # No value is needed, we just
             # care if it exists. Sets aren't viable
             # because only keys can expire.
-            pipe.set(key_host, '')
+            pipe.sadd(key_host, '')
 
             pipe.execute()
 
diff --git a/tests/drivers/test_matchmaker_redis.py b/tests/drivers/test_matchmaker_redis.py
index 95bde9e8a..a36e14af6 100644
--- a/tests/drivers/test_matchmaker_redis.py
+++ b/tests/drivers/test_matchmaker_redis.py
@@ -46,6 +46,7 @@ class RedisMatchMakerTest(test_utils.BaseTestCase):
             "network": ["controller1", "node1", "node2", "node3"],
             "cert": ["controller1"],
             "console": ["controller1"],
+            "l3_agent.node1": ["node1"],
             "consoleauth": ["controller1"]}
         self.matcher = matchmaker_redis.MatchMakerRedis()
         self.populate()
@@ -70,6 +71,10 @@ class RedisMatchMakerTest(test_utils.BaseTestCase):
         self.assertEqual(
             sorted(self.matcher.redis.smembers('cert')),
             ['cert.controller1', 'cert.keymaster'])
+        self.matcher.register('l3_agent.node1', 'node1')
+        self.assertEqual(
+            sorted(self.matcher.redis.smembers('l3_agent.node1')),
+            ['l3_agent.node1.node1'])
 
     def test_unregister(self):
         self.matcher.unregister('conductor', 'controller1')