diff --git a/src/main/scala/ignition/core/jobs/CoreJobRunner.scala b/src/main/scala/ignition/core/jobs/CoreJobRunner.scala
index 2c904b5c..5d8b6e04 100644
--- a/src/main/scala/ignition/core/jobs/CoreJobRunner.scala
+++ b/src/main/scala/ignition/core/jobs/CoreJobRunner.scala
@@ -80,6 +80,10 @@ object CoreJobRunner {
 
 
       val builder = SparkSession.builder
+      builder.config("spark.executor.memory", config.executorMemory)
+      builder.config("spark.eventLog.dir", "file:///media/tmp/spark-events")
+
+      builder.master(config.master)
       builder.appName(appName)
 
       builder.config("spark.hadoop.mapred.output.committer.class", classOf[DirectOutputCommitter].getName())
diff --git a/tools/cluster.py b/tools/cluster.py
index 966dd987..421b6940 100755
--- a/tools/cluster.py
+++ b/tools/cluster.py
@@ -245,8 +245,6 @@ def launch(cluster_name, slaves,
 
     assert not master_instance_type or master_instance_type == instance_type, 'Different master instance type is currently unsupported'
     assert not master_ami or master_ami == ami, 'Different master ami is currently unsupported'
-    assert not ondemand, 'On demand is unsupported'
-    assert master_spot, 'On demand master is currently unsupported'
 
     all_args = locals()