NTO: Cloud provider specific TuneD profiles

Author: jmencak

modules/custom-tuning-specification.adoc

@@ -174,3 +174,47 @@ To minimize node reboots, label the target nodes with a label the machine config
 //     matchLabels:
 //       node-role.kubernetes.io/worker-custom: ""
 // EOF
+
+*Cloud provider-specific TuneD profiles*
+
+With this functionality, all Cloud provider-specific nodes can conveniently
+be assigned a TuneD profile specifically tailored to a given Cloud provider
+on a {product-title} cluster. This can be accomplished without adding
+additional node labels or grouping nodes into machine config pools.
+
+This functionality takes advantage of `spec.providerID` node object values
+in the form of `<cloud-provider>://<cloud-provider-specific-id>` and writes
+the file `/var/lib/tuned/provider` with the value `<cloud-provider>` in NTO
+operand containers.  The content of this file is then used by TuneD to load
+`provider-<cloud-provider>` profile if such profile exists.
+
+The `openshift` profile that both `openshift-control-plane` and
+`openshift-node` profiles inherit settings from is now updated to use
+this functionality through the use of conditional profile loading.
+Neither NTO nor TuneD currently ship any Cloud provider-specific profiles.
+However, it is possible to create a custom profile `provider-<cloud-provider>`
+that will be applied to all Cloud provider-specific cluster nodes.
+
+.Example GCE Cloud provider profile
+[source,yaml]
+----
+apiVersion: tuned.openshift.io/v1
+kind: Tuned
+metadata:
+  name: provider-gce
+  namespace: openshift-cluster-node-tuning-operator
+spec:
+  profile:
+  - data: |
+      [main]
+      summary=GCE Cloud provider-specific profile
+      # Your tuning for GCE Cloud provider goes here.
+    name: provider-gce
+----
+
+[NOTE]
+====
+Due to profile inheritance, any setting specified in the
+`provider-<cloud-provider>` profile will be overwritten by the `openshift`
+profile and its child profiles.
+====