maximum of 1 hpc per node
diff --git a/xos/hpc/models.py b/xos/hpc/models.py
index a3b7c90..1cd51ce 100644
--- a/xos/hpc/models.py
+++ b/xos/hpc/models.py
@@ -35,7 +35,7 @@
         scale = getattr(self, "set_scale", None)
         if scale is not None:
             exclude_slices = [x for x in self.slices.all() if "cmi" in x.name]
-            self.adjust_scale(slice_hint="hpc", scale=scale, exclusive_slices = exclude_slices)
+            self.adjust_scale(slice_hint="hpc", scale=scale, exclusive_slices = exclude_slices, max_per_node=1)
 
 class ServiceProvider(PlCoreBase):
     class Meta: