Merge pull request #30642 from sjhala-ccs/cnv-10988

CNV-10988 Updated virt sizing guidelines

Author: sjhala-ccs

modules/virt-cluster-resource-requirements.adoc

@@ -35,10 +35,14 @@ Additionally, {VirtProductName} environment resources require a total of 2179 Mi
 
 ----
 Memory overhead per virtual machine ≈ (1.002 * requested memory) + 146 MiB  \
-                + (8 * number of vCPUs) + (16 MiB * number of graphics devices)
+                + 8 * (number of vCPUs) \ <1>
+             + 16 MiB * (number of graphics devices) <2>
 ----
 
-Add 1 GiB to the above result if your environment includes a Single Root I/O Virtualization (SR-IOV) network device or a Graphics Processing Unit (GPU).
+<1> Number of virtual CPUs requested by the virtual machine
+<2> Number of virtual graphics cards requested by the virtual machine
+
+If your environment includes a Single Root I/O Virtualization (SR-IOV) network device or a Graphics Processing Unit (GPU), allocate 1 GiB additional memory overhead for each device.
 
 
 [id="CPU-overhead_{context}"]
@@ -49,16 +53,21 @@ Calculate the cluster processor overhead requirements for {VirtProductName} by u
 .Cluster CPU overhead
 
 ----
-CPU overhead for infrastructure nodes ≈ 4
+CPU overhead for infrastructure nodes ≈ 4 cores
 ----
 
+{VirtProductName} increases the overall utilization of cluster level services such as logging, routing, and monitoring. To account for this workload, ensure that nodes that host infrastructure components have capacity allocated for 4 additional cores (4000 millicores) distributed across those nodes.
+
 ----
-CPU overhead for worker nodes ≈ 2 + CPU overhead per virtual machine
+CPU overhead for worker nodes ≈ 2 cores + CPU overhead per virtual machine
 ----
 
+Each worker node that hosts virtual machines must have capacity for 2 additional cores (2000 millicores) for {VirtProductName} management workloads in addition to the CPUs required for virtual machine workloads.
+
+
 .Virtual machine CPU overhead
 
-CPU overhead per virtual machine is subjective. If dedicated CPUs are requested, there is a 1:1 impact on the cluster CPU overhead requirement. Otherwise, there are no specific rules about how many CPUs a virtual machine requires.
+If dedicated CPUs are requested, there is a 1:1 impact on the cluster CPU overhead requirement. Otherwise, there are no specific rules about how many CPUs a virtual machine requires.
 
 
 [id="storage-overhead_{context}"]
@@ -69,9 +78,11 @@ Use the guidelines below to estimate storage overhead requirements for your {Vir
 .Cluster storage overhead
 
 ----
-Aggregated storage overhead per node ≈ 10.36 GiB
+Aggregated storage overhead per node ≈ 10 GiB
 ----
 
+10 GiB is the estimated on-disk storage impact for each node in the cluster when you install {VirtProductName}.
+
 .Virtual machine storage overhead
 
 Storage overhead per virtual machine depends on specific requests for resource allocation within the virtual machine. The request could be for ephemeral storage on the node or storage resources hosted elsewhere in the cluster. {VirtProductName} does not currently allocate any additional ephemeral storage for the running container itself.
@@ -80,4 +91,4 @@ Storage overhead per virtual machine depends on specific requests for resource a
 [id="example-scenario_{context}"]
 == Example
 
-As a cluster administrator, if you plan to host 10 virtual machines in the cluster, each with 1 GiB of RAM and 2 vCPUs, the memory impact across the cluster is 11.68 GiB.
+As a cluster administrator, if you plan to host 10 virtual machines in the cluster, each with 1 GiB of RAM and 2 vCPUs, the memory impact across the cluster is 11.68 GiB. The estimated on-disk storage impact for each node in the cluster is 10 GiB and the CPU impact for worker nodes that host virtual machine workloads is a minimum of 2 cores.