WIP - CASM-4977: Procedure to upgrade NCN and CN with different CSM version based images

upgrade/Creating_hybrid_configurations.md

@@ -0,0 +1,44 @@
+# Upgrading management and managed nodes with different CSM versions using IUF
+
+For certain use cases, there may be a need to combine different recipes of CSM to bring up the
+management and managed nodes. For example, if a feature which supports a specific
+CPU architecture for managed nodes is needed and that is present in a different recipe of CSM
+than the version of CSM that will be run on management nodes.
+
+## Procedure
+
+1. Decide the recipes for management and managed nodes. For example, use recipe `a.b.c`,
+which contains CSM version `1.5.x` for managed nodes and use recipe `x.y.z`, which contains
+CSM version `1.6.x`, for management nodes.
+
+1. Ensure that the CSM cluster is operational with the lowest among the selected recipes for both
+management and managed nodes.
+
+   If it is necessary to upgrade CSM to the lowest among the selected recipes, then
+   use the [Upgrade CSM and additional products with IUF](../operations/iuf/workflows/upgrade_csm_and_additional_products_with_iuf.md) procedure to upgrade CSM. In the
+   above example, the upgrade would be to recipe `a.b.c`, which contains CSM version
+   `1.5.x`, for both management and managed nodes.
+
+1. Go through the `product_vars.yaml` file of both the recipes and come up with a set
+of products and versions across the recipes which have to be upgraded for CSM version **`1.6.x`**.
+
+1. Use the [Upgrade CSM and additional products with IUF](../operations/iuf/workflows/upgrade_csm_and_additional_products_with_iuf.md) procedure to upgrade CSM until
+[step 9, Managed rollout](../operations/iuf/workflows/managed_rollout.md), skip section
+"2.2 Compute Nodes". That is, do not upgrade compute nodes to the recipe `x.y.z`
+with CSM version `1.6.x` in order to keep the compute nodes on the `a.b.c` recipe
+with CSM version `1.5.x`.
+
+## Post install Testing
+
+Execute the NCN health checks to validate that management nodes are executing correctly.
+
+```bash
+/opt/cray/tests/install/ncn/automated/ncn-healthcheck-master
+/opt/cray/tests/install/ncn/automated/ncn-healthcheck-worker
+/opt/cray/tests/install/ncn/automated/ncn-healthcheck-storage
+/opt/cray/tests/install/ncn/automated/ncn-kubernetes-checks 
+```
+
+Execute the post install checks to validate that the managed nodes are executing correctly.
+Refer to [Post Install Check](../operations/iuf/stages/post_install_check.md) on
+running post install checks.

upgrade/README.md

@@ -11,6 +11,7 @@ software. Choose the appropriate procedure from the sections below.
     * [Option 2: Upgrade only additional HPE Cray EX software products](#option-2-upgrade-only-additional-hpe-cray-ex-software-products)
     * [Option 3: Upgrade only CSM](#option-3-upgrade-only-csm)
 * [CSM patch version upgrade](#csm-patch-version-upgrade)
+* [Upgrading management and managed nodes with different CSM versions using IUF](#upgrading-management-and-managed-nodes-with-different-csm-versions-using-iuf)
 
 ## Release Notes
 
@@ -91,3 +92,7 @@ CSM 1.6 patch upgrades. Instead, consider upgrading to the latest CSM 1.6 patch
 
 There are no CSM 1.6 patch versions currently available. When any become available, they will
 be listed here.
+
+## Upgrading management and managed nodes with different CSM versions using IUF
+
+Follow the procedure [Upgrading management and managed nodes with different CSM versions using IUF](Creating_hybrid_configurations.md) when planning to upgrade management and managed nodes with different versions of CSM.