diff --git a/qa/tasks/ceph_fuse.py b/qa/tasks/ceph_fuse.py
index d01c313110b..2712229f972 100644
--- a/qa/tasks/ceph_fuse.py
+++ b/qa/tasks/ceph_fuse.py
@@ -108,9 +108,7 @@ def task(ctx, config):
         if client_config is None:
             client_config = {}
         # top level overrides
-        for k, v in top_overrides.items():
-            if v is not None:
-                client_config[k] = v
+        misc.deep_merge(client_config, top_overrides)
         # mount specific overrides
         client_config_overrides = overrides.get(entity)
         misc.deep_merge(client_config, client_config_overrides)
diff --git a/qa/tasks/kclient.py b/qa/tasks/kclient.py
index be75286bd0d..d7bc9fa835b 100644
--- a/qa/tasks/kclient.py
+++ b/qa/tasks/kclient.py
@@ -84,9 +84,7 @@ def task(ctx, config):
         if client_config is None:
             client_config = {}
         # top level overrides
-        for k, v in top_overrides.items():
-            if v is not None:
-                client_config[k] = v
+        deep_merge(client_config, top_overrides)
         # mount specific overrides
         client_config_overrides = overrides.get(entity)
         deep_merge(client_config, client_config_overrides)