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@@ -12,4 +12,8 @@ Read maas-setup.sh. The script is not fully automated and requires manual interv
 
 ## Requirements
 
-You need a reasonably powerful machine, 4 or more cores with 32 GB of RAM and 500GB of free disk space. Assumes a fresh install of Ubuntu server on the machine.
+You need a reasonably powerful **bare metal** machine, 4 or more cores with 32 GB of RAM and 500GB of free disk space. Assumes a fresh install of Ubuntu server (20.04 or higher) on the machine. 
+
+The reason you need a bare metal machine is because nesting multiple layers of VMs will not work and/or have performance problems.
+
+Note: this tutorial has not been tested on versions prior to 20.04.