Merge pull request #89809 from lahinson/osdocs-12514-arch-considerations

[OSDOCS-12514]: Adding architecture requirements for HCP

Author: lahinson

hosted_control_planes/hcp-prepare/hcp-requirements.adoc

@@ -6,12 +6,14 @@ include::_attributes/common-attributes.adoc[]
 
 toc::[]
 
-In the context of {hcp}, a _management cluster_ is an {product-title} cluster where the HyperShift Operator is deployed and where the control planes for hosted clusters are hosted. 
-
-The management cluster and worker nodes must run on the same type of infrastructure. For example, you can run both the management cluster and the worker nodes on-premise, such as on a bare-metal platform or on {VirtProductName}. In addition, you can run both the management cluster and the worker nodes on cloud infrastructure, such as {aws-first}. However, you cannot run your management cluster on the cloud and your worker nodes on-premise, or the other way around.
+In the context of {hcp}, a _management cluster_ is an {product-title} cluster where the HyperShift Operator is deployed and where the control planes for hosted clusters are hosted.
 
 The control plane is associated with a hosted cluster and runs as pods in a single namespace. When the cluster service consumer creates a hosted cluster, it creates a worker node that is independent of the control plane.
 
+You can run both the management cluster and the worker nodes on-premise, such as on a bare-metal platform or on {VirtProductName}. In addition, you can run both the management cluster and the worker nodes on cloud infrastructure, such as {aws-first}. If you use a mixed infrastructure, such as running the management cluster on {aws-short} and your worker nodes on-premise, or running your worker nodes on {aws-short} and your management cluster on-premise, you must use the `PublicAndPrivate` publishing strategy and follow the latency requirements in the support matrix.
+
+In Bare Metal Host (BMH) deployments, where the Bare Metal Operator starts machines, the hosted control plane must be able to reach baseboard management controllers (BMCs). If your security profile does not permit the Cluster Baremetal Operator to access the network where the BMHs have their BMCs in order to enable Redfish automation, you can use BYO ISO support. However, in BYO mode, {product-title} cannot automate the powering on of BMHs.
+
 include::modules/hcp-support-matrix.adoc[leveloffset=+1]
 
 [role="_additional-resources"]

modules/hcp-support-matrix.adoc

@@ -46,7 +46,7 @@ For hosted clusters, no direct relationship exists between the management cluste
 
 [NOTE]
 ====
-Ensure a maximum latency of 200 ms between the management cluster and hosted clusters.
+Ensure a maximum latency of 200 ms between the management cluster and hosted clusters. This requirement is especially important for mixed infrastructure deployments, such as when your management cluster is on {aws-short} and your worker nodes are on-premise.
 ====
 
 The following table maps {mce-short} versions to the hosted cluster versions that you can create by using the HyperShift Operator that is associated with that version of {mce-short}: