TELCODOCS-1481 CNF-9121 Reduce DU Profile Apply Time

Author: slovern

edge_computing/ztp-deploying-far-edge-sites.adoc

@@ -28,6 +28,8 @@ include::modules/ztp-deploying-a-site.adoc[leveloffset=+1]
 
 * xref:../edge_computing/ztp-deploying-far-edge-sites.adoc#ztp-sno-siteconfig-config-reference_ztp-deploying-far-edge-sites[{sno-caps} SiteConfig CR installation reference]
 
+include::modules/ztp-sno-accelerated-ztp.adoc[leveloffset=+2]
+
 include::modules/ztp-sno-siteconfig-config-reference.adoc[leveloffset=+2]
 
 [role="_additional-resources"]

modules/ztp-deploying-a-site.adoc

@@ -1,6 +1,6 @@
 // Module included in the following assemblies:
 //
-// * scalability_and_performance/ztp_far_edge/ztp-deploying-far-edge-sites.adoc
+// * edge_computing/ztp-deploying-far-edge-sites.adoc
 
 :_mod-docs-content-type: PROCEDURE
 [id="ztp-deploying-a-site_{context}"]

modules/ztp-sno-accelerated-ztp.adoc

@@ -0,0 +1,80 @@
+// Module included in the following assemblies:
+//
+// * edge_computing/ztp-deploying-far-edge-sites.adoc
+
+:_mod-docs-content-type: CONCEPT
+[id="ztp-sno-accelerated-ztp_{context}"]
+= Accelerated provisioning of {ztp}
+
+:FeatureName: Accelerated provisioning of {ztp}
+include::snippets/technology-preview.adoc[]
+
+You can reduce the time taken for cluster installation by using accelerated provisioning of {ztp} for {sno}. 
+Accelerated ZTP speeds up installation by applying Day 2 manifests derived from policies at an earlier stage. 
+
+[IMPORTANT]
+====
+Accelerated provisioning of {ztp} is supported only when installing {sno} with Assisted Installer. Otherwise this installation method will fail.
+====
+
+[id="activating-accelerated-ztp_{context}"]
+== Activating accelerated ZTP
+
+You can activate accelerated ZTP using the `spec.clusters.clusterLabels.accelerated-ztp` label, as in the following example:
+
+.Example Accelerated ZTP `SiteConfig` CR.
+[source,yaml]
+----
+apiVersion: ran.openshift.io/v2
+kind: SiteConfig
+metadata:
+  name: "example-sno"
+  namespace: "example-sno"
+spec:
+  baseDomain: "example.com"
+  pullSecretRef:
+    name: "assisted-deployment-pull-secret"
+  clusterImageSetNameRef: "openshift-4.10"
+  sshPublicKey: "ssh-rsa AAAA..."
+  clusters:
+  # ...
+    clusterLabels:
+        common: true
+        group-du-sno: ""
+        sites : "example-sno"
+        accelerated-ztp: full
+
+----
+
+You can use `accelerated-ztp: full` to fully automate the accelerated process. 
+{ztp} updates the `AgentClusterInstall` resource with a reference to the accelerated {ztp} `ConfigMap`, and includes resources extracted from policies by {cgu-operator}, and accelerated ZTP job manifests. 
+
+If you use `accelerated-ztp: partial`, {ztp} does not include the accelerated job manifests, but includes policy-derived objects created during the cluster installation of the following `kind` types:
+
+* `PerformanceProfile.performance.openshift.io`
+* `Tuned.tuned.openshift.io`
+* `Namespace`
+* `CatalogSource.operators.coreos.com`
+* `ContainerRuntimeConfig.machineconfiguration.openshift.io`
+
+This partial acceleration can reduce the number of reboots done by the node when applying resources of the kind `Performance Profile`, `Tuned`, and `ContainerRuntimeConfig`. 
+{cgu-operator} installs the Operator subscriptions derived from policies after {rh-rhacm} completes the import of the cluster, following the same flow as standard {ztp}.
+
+The benefits of accelerated ZTP increase with the scale of your deployment. 
+Using `accelerated-ztp: full` gives more benefit on a large number of clusters. 
+With a smaller number of clusters, the reduction in installation time is less significant.
+Full accelerated ZTP leaves behind a namespace and a completed job on the spoke that need to be manually removed.
+
+One benefit of using `accelerated-ztp: partial` is that you can override the functionality of the on-spoke job if something goes wrong with the stock implementation or if you require a custom functionality.
+
+[id="the-accelerated-ztp-process_{context}"]
+== The accelerated ZTP process
+
+Accelerated ZTP uses an additional `ConfigMap` to create the resources derived from policies on the spoke cluster.  
+The standard `ConfigMap` includes manifests that the {ztp} workflow uses to customize cluster installs. 
+
+{cgu-operator} detects that the `accelerated-ztp` label is set and then creates a second `ConfigMap`.
+As part of accelerated ZTP, the `SiteConfig` generator adds a reference to that second `ConfigMap` using the naming convention `<spoke-cluster-name>-aztp`. 
+
+After {cgu-operator} creates that second `ConfigMap`, it finds all policies bound to the managed cluster and extracts the {ztp} profile information. 
+{cgu-operator} adds the {ztp} profile information to the `<spoke-cluster-name>-aztp` `ConfigMap` custom resource (CR) and applies the CR to the hub cluster API.