fix: disable parallel operations for Pulumi as backend does not support that, yet

cloudbender/cli.py

@@ -342,10 +342,28 @@ def _render(stacks):
             logger.info("{} uses Pulumi, render skipped.".format(s.stackname))
 
 
+def _anyPulumi(step):
+    for stack in step:
+        if stack.mode == "pulumi":
+            return True
+
+    return False
+
+
 def _provision(cb, stacks):
     """Utility function to reuse code between tasks"""
     for step in sort_stacks(cb, stacks):
         if step:
+            # if there are any Pulumi stacks in the step execute serial
+            if _anyPulumi(step):
+                for stack in step:
+                    status = stack.get_status()
+                    if not status:
+                        stack.create()
+                    else:
+                        stack.update()
+
+            else:
                 with ThreadPoolExecutor(max_workers=len(step)) as group:
                     futures = []
                     for stack in step: