Merge pull request #228705 from kaarthis/nodeosupgrade

nodeosupgradechannel

Author: prmerger-automator[bot]

articles/aks/auto-upgrade-node-image.md

@@ -9,15 +9,13 @@ ms.date: 02/03/2023
 
 # Automatically upgrade Azure Kubernetes Service cluster node operating system images (preview)
 
-AKS supports upgrading the images on a node so your cluster is up to date with the newest operating system (OS) and runtime updates. AKS regularly provides new node OS images with the latest updates, so it's beneficial to upgrade your node's images regularly for the latest AKS features and to maintain security. Before learning about auto-upgrade, make sure you understand upgrade fundamentals by reading [Upgrade an AKS cluster][upgrade-aks-cluster].
-
-The latest AKS node image information can be found by visiting the [AKS release tracker][release-tracker].
+AKS now supports an exclusive channel dedicated to controlling node-level OS security updates. This channel, referred to as the node OS auto-upgrade channel, works in tandem with the existing [Autoupgrade][auto-upgrade] channel which is used for Kubernetes version upgrades. 
 
 [!INCLUDE [preview features callout](./includes/preview/preview-callout.md)]
 
 ## Why use node OS auto-upgrade
 
-Node OS auto-upgrade provides a set once and forget mechanism that yields tangible time and operational cost benefits. By enabling auto-upgrade, you can ensure your clusters are up to date and don't miss the latest AKS features or patches from AKS.
+This channel is exclusively meant to control node OS security updates. You can use this channel to disable [unattended upgrades][unattended-upgrades]. You can schedule maintenance without worrying about [Kured][kured] for security patches, provided you choose either the `SecurityPatch` or `NodeImage` options for `nodeOSUpgradeChannel`. By using this channel, you can run node image upgrades in tandem with Kubernetes version auto-upgrade channels like `Stable` and `Rapid`.
 
 ## Prerequisites
 
@@ -49,7 +47,9 @@ az provider register --namespace Microsoft.ContainerService
 
 ## Limitations
 
-If using the `node-image` cluster auto-upgrade channel or the `NodeImage` node image auto-upgrade channel, Linux [unattended upgrades][unattended-upgrades] will be disabled by default.
+If using the `node-image` cluster auto-upgrade channel or the `NodeImage` node OS auto-upgrade channel, Linux [unattended upgrades][unattended-upgrades] will be disabled by default. You can't change node OS auto-upgrade channel value if your cluster auto-upgrade channel is `node-image`. In order to set the node OS auto-upgrade channel values , make sure the [cluster auto-upgrade channel][Autoupgrade] is not `node-image`. 
+
+The nodeosupgradechannel is not supported on Mariner and Windows OS nodepools. 
 
 ## Using node OS auto-upgrade
 
@@ -96,3 +96,5 @@ For more information on Planned Maintenance, see [Use Planned Maintenance to sch
 [az-feature-show]: /cli/azure/feature#az-feature-show
 [upgrade-aks-cluster]: upgrade-cluster.md
 [unattended-upgrades]: https://help.ubuntu.com/community/AutomaticSecurityUpdates
+[Autoupgrade]: auto-upgrade-cluster.md
+[kured]: node-updates-kured.md