Merge pull request #80335 from xiaoyu74/update_rosa_hcp_vpc_subnets

Update VPC requirements for creating ROSA HCP clusters

Author: EricPonvelle

modules/rosa-hcp-vpc-manual.adoc

@@ -23,8 +23,11 @@ If you choose to manually create your Virtual Private Cloud (VPC) instead of usi
 | You need one availability zone for a single zone, and you need three for availability zones for multi-zone.
 
 | Public subnet
-| You must have one public subnet with a NAT gateway for public clusters. Private clusters do not need a public subnet.
+| You must have one public subnet with an internet gateway for public clusters.
+
+| Private subnet
+| You must have exactly one private subnet in each availability zone (AZ) for installing machine pools in ROSA HCP clusters. A NAT gateway may be associated with this subnet to allow outbound internet access for the instances. Private clusters do not need a public subnet.
 
 | DNS hostname and resolution
 | You must ensure that the DNS hostname and resolution are enabled.
-|===
+|===