OSDOCS-12270:deprecating notice

Author: brendan-daly-red-hat

modules/rhel-compute-overview.adoc

@@ -19,4 +19,6 @@ For installer-provisioned infrastructure clusters, you must manually add {op-sys
 * Because removing {product-title} from a machine in the cluster requires destroying the operating system, you must use dedicated hardware for any {op-system-base} machines that you add to the cluster.
 
 * Swap memory is disabled on all {op-system-base} machines that you add to your {product-title} cluster. You cannot enable swap memory on these machines.
+
+* The installation of package-based {op-system-base} has been deprecated. {op-system-base} will be removed in a future release. {op-system} image layering will replace this feature and it supports installing additional packages on the base operating system of your worker nodes.
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