diff --git a/versions/slave/airootfs/discover.py b/versions/slave/airootfs/discover.py
index b8f7478..64ee89e 100644
--- a/versions/slave/airootfs/discover.py
+++ b/versions/slave/airootfs/discover.py
@@ -52,6 +52,8 @@ def selfInfo():
 
 
 def loadHosts():
+    global HOSTS, MASTER
+
     try:
         with open('/etc/slurm-llnl/hosts.json', 'r') as file:
             HOSTS = json.load(file)
@@ -70,6 +72,9 @@ def updateHosts():
         json.dump(HOSTS, outfile)
 
 def generateSlurmConfig(source, target):
+    if MASTER is None:
+        return
+
     hosts = f"NodeName={socket.gethostname()} NodeAddr={get_ip()} CPUs={os.cpu_count()} State=UNKNOWN\n" # first is my self
     noMasterHosts = ""
     for host in HOSTS.values():