Disconnected doc section

Instead of pointing folks to a random blog post let's add a proper
disconnected section to our docs

Author: mbaldessari

content/learn/disconnected-installation.adoc

@@ -0,0 +1,199 @@
+---
+menu:
+  learn:
+    parent: Patterns quick start
+title: Deploying in a disconnected network
+weight: 22
+aliases: /learn/disconnected-installation/
+---
+
+:toc:
+:_content-type: ASSEMBLY
+include::modules/comm-attributes.adoc[]
+
+[id="disconnected-installation"]
+== Deploying a validated pattern in a disconnected network
+
+A disconnected (air-gapped) network is an infrastructure that is isolated from
+external internet access. Deploying {solution-name-upstream} in such an
+environment requires additional steps to mirror container images, configure
+internal registries, and adjust pattern configuration files.
+
+This guide walks through deploying the {mcg-pattern} on {ocp} 4.19 in
+a disconnected network. The same approach applies to other validated patterns,
+though the specific list of images and operators will vary by pattern.
+
+== Prerequisites
+
+* One or more {ocp} clusters deployed in a disconnected network
+* An OCI-compliant registry accessible from the disconnected network (referred
+  to as `registry.internal.disconnected.net` in this guide)
+* A Git repository accessible from the disconnected network
+* (Optional) A VM in the disconnected network from which to run commands
+
+[NOTE]
+====
+Deploying {ocp} in a disconnected network is out of scope for this guide. See the
+https://docs.redhat.com/en/documentation/openshift_container_platform/4.19/html-single/disconnected_environments/index#about-installing-oc-mirror-v2[{ocp} disconnected environments documentation]
+for details.
+====
+
+== Mirroring container images
+
+The first step is to mirror all required container images to the internal
+registry. The exact list of images depends on the pattern, the {ocp} version,
+and the required operators. The list of images will depend on the pattern,
+the below is an example for Multicloud GitOps.
+
+This guide uses `oc mirror --v2`. Create an `imageset-config.yaml` file that
+lists the required platform images, operators, and additional images:
+
+[source,yaml]
+----
+kind: ImageSetConfiguration
+apiVersion: mirror.openshift.io/v2alpha1
+mirror:
+  platform:
+    graph: true
+    channels:
+    - name: stable-4.19
+      type: ocp
+  operators:
+  - catalog: registry.redhat.io/redhat/redhat-operator-index:v4.19
+    packages:
+      - name: lvms-operator
+      - name: advanced-cluster-management
+        channels:
+          - name: release-2.14
+      - name: openshift-external-secrets-operator
+        channels:
+          - name: stable-v1
+      - name: multicluster-engine
+        channels:
+          - name: stable-2.9
+      - name: openshift-gitops-operator
+        channels:
+          - name: gitops-1.19
+  - catalog: registry.redhat.io/redhat/community-operator-index:v4.19
+    packages:
+      - name: patterns-operator
+  additionalImages:
+  - name: registry.redhat.io/ubi9/ubi-minimal:latest
+  - name: registry.connect.redhat.com/hashicorp/vault:1.20.2-ubi
+  - name: registry.access.redhat.com/ubi8/httpd-24:10.0-1755779646
+  - name: ghcr.io/external-secrets/external-secrets:v0.10.2-ubi
+  # Validated Patterns Helm charts
+  - name: quay.io/validatedpatterns/acm:0.1.17
+  - name: quay.io/validatedpatterns/clustergroup:0.9.41
+  - name: quay.io/validatedpatterns/gitea:0.0.3
+  - name: quay.io/validatedpatterns/golang-external-secrets:0.1.5
+  - name: quay.io/validatedpatterns/openshift-external-secrets:0.0.3
+  - name: quay.io/validatedpatterns/hashicorp-vault:0.1.6
+  - name: quay.io/validatedpatterns/utility-container:latest
+  - name: quay.io/validatedpatterns/imperative-container:v1
+  - name: quay.io/validatedpatterns/pattern-install:0.0.11
+  - name: docker.io/gitea/gitea:1.22.6-rootless
+----
+
+Run the mirror command, specifying a local cache directory and the target
+registry:
+
+[source,sh]
+----
+oc mirror --config=/var/cache/oc-mirror/imageset-config.yaml \
+    --workspace file:///var/cache/oc-mirror/workspace \
+    docker://registry.internal.disconnected.net --v2
+----
+
+Once mirroring completes, `oc mirror` generates resource files under
+`/var/cache/oc-mirror/workspace/working-dir/cluster-resources`. Apply these to
+the cluster so that it can resolve images from the internal registry:
+
+[source,sh]
+----
+cd /var/cache/oc-mirror/workspace/working-dir/cluster-resources
+oc apply -f cs-community-operator-index-v4-19.yaml \
+  cs-redhat-operator-index-v4-19.yaml idms-oc-mirror.yaml \
+  itms-oc-mirror.yaml
+----
+
+[IMPORTANT]
+====
+The catalog source names generated by `oc mirror` (for example,
+`cs-redhat-operator-index-v4-19`) are needed in the next step when configuring
+the pattern's values files.
+====
+
+== Configuring the pattern for disconnected use
+
+The pattern's values files must be updated to reference the mirrored catalog
+sources and the internal Helm chart registry. Ensure your local Git clone has
+its `origin` remote pointing to the disconnected Git server (verify with
+`git remote -v`).
+
+=== values-global.yaml
+
+Point the Helm chart repository to the internal registry and configure operator
+sources:
+
+[source,yaml]
+----
+main:
+  multiSourceConfig:
+    enabled: true
+    clusterGroupChartVersion: "0.9.*"
+    helmRepoUrl: registry.internal.disconnected.net/validatedpatterns
+  patternsOperator:
+    source: cs-community-operator-index-v4-19
+  gitops:
+    operatorSource: cs-redhat-operator-index-v4-19
+----
+
+=== values-hub.yaml
+
+Configure operator sources for hub-specific components:
+
+[source,yaml]
+----
+acm:
+  mce_operator:
+    source: cs-redhat-operator-index-v4-19
+
+clusterGroup:
+  subscriptions:
+    acm:
+      name: advanced-cluster-management
+      namespace: open-cluster-management
+      channel: release-2.14
+      source: cs-redhat-operator-index-v4-19
+----
+
+Commit and push these changes to the disconnected Git server.
+
+== Deploying the pattern
+
+With images mirrored and the pattern configured, deploy from a machine that has
+access to both the disconnected cluster and the Git repository:
+
+[source,sh]
+----
+# Point the installer to the mirrored Helm chart
+export PATTERN_DISCONNECTED_HOME=registry.internal.disconnected.net/validatedpatterns
+./pattern.sh make install
+----
+
+The cluster will converge to the desired state and the pattern will be
+installed.
+
+== Adapting this guide for other patterns
+
+The steps above use the {mcg-pattern} as an example. When deploying a different
+pattern in a disconnected network:
+
+* Identify all operators required by the pattern and add them to the
+  `imageset-config.yaml` operator list.
+* Identify all additional container images referenced by the pattern's Helm
+  charts and add them to the `additionalImages` list.
+* Update each values file (`values-global.yaml`, `values-hub.yaml`, and any
+  site-specific values files) to reference the correct catalog source names for
+  all operator subscriptions.

content/learn/quickstart.adoc

@@ -55,5 +55,5 @@ Before beginning, ensure you have the following:
 * An OCI-compliant registry that is accessible from the disconnected network 
 * A Git Repository that is accessible from the disconnected network
 
-For more information on disconnected installation, see link:/blog/2024-10-12-disconnected/[Validated Patterns in a disconnected Network].
+For more information on disconnected installation, see link:/learn/disconnected-installation/[Deploying in a disconnected network].