diff --git a/teuthology/suite/merge.py b/teuthology/suite/merge.py
index f13058e47..9c2f634d0 100644
--- a/teuthology/suite/merge.py
+++ b/teuthology/suite/merge.py
@@ -1,4 +1,5 @@
 import copy
+import itertools
 import logging
 import lupa
 import os
@@ -115,13 +116,15 @@ def config_merge(configs, suite_name=None, **kwargs):
     the entire job (config) from the list.
     """
     seed = kwargs.setdefault('seed', 1)
+    base_config = kwargs.setdefault('base_config', {})
     if not isinstance(seed, int):
         log.debug("no valid seed input: using 1")
         seed = 1
     log.debug("configuring Lua randomseed to %d", seed)
     L.execute(f'local math = require"math"; math.randomseed({seed});')
     new_script = L.eval('new_script')
-    yaml_cache = {}
+    base_config_path = '\0' # not a valid path
+    yaml_cache = {base_config_path: base_config}
     for desc, paths in configs:
         log.debug("merging config %s", desc)
 
@@ -130,7 +133,7 @@ def config_merge(configs, suite_name=None, **kwargs):
 
         yaml_complete_obj = {}
         deep_merge(yaml_complete_obj, dict(TEUTHOLOGY_TEMPLATE))
-        for path in paths:
+        for path in itertools.chain((base_config_path,), paths):
             if path not in yaml_cache:
                 with open(path) as f:
                     txt = f.read()
diff --git a/teuthology/suite/run.py b/teuthology/suite/run.py
index 7df601385..124d860f5 100644
--- a/teuthology/suite/run.py
+++ b/teuthology/suite/run.py
@@ -514,7 +514,6 @@ def collect_jobs(self, arch, configs, newest=False, limit=0):
                 '--description', description,
                 '--',
             ])
-            arg.extend(self.base_yaml_paths)
 
             parsed_yaml_txt = yaml.dump(parsed_yaml)
             arg.append('-')