Merge pull request #40208 from Amrita42/BZ2013874

BZ2013874: Added a note to use same Ignition config file and ISO

Author: bergerhoffer

machine_management/user_infra/adding-bare-metal-compute-user-infra.adoc

@@ -24,6 +24,11 @@ If you do not have access to the {op-system-first} images that were used to crea
 
 Before you add more compute machines to a cluster that you installed on bare metal infrastructure, you must create {op-system} machines for it to use. You can either use an ISO image or network PXE booting to create the machines.
 
+[NOTE]
+====
+You must use the same ISO image that you used to install a cluster to deploy all new nodes in a cluster. It is recommended to use the same Ignition config file. The nodes automatically upgrade themselves on the first boot before running the workloads. You can add the nodes before or after the upgrade.
+====
+
 include::modules/machine-user-infra-machines-iso.adoc[leveloffset=+2]
 
 include::modules/machine-user-infra-machines-pxe.adoc[leveloffset=+2]