Update upgrade-cluster.md

Author: American-Dipper

articles/aks/upgrade-cluster.md

@@ -276,7 +276,7 @@ In addition to manually upgrading a cluster, you can set an auto-upgrade channel
 
 ## Special considerations for node pools that span multiple Availability Zones
 
-AKS uses best-effort zone balancing in node groups. During an Upgrade surge, zone(s) for the surge node(s) in virtual machine scale sets is unknown ahead of time. This can temporarily cause an unbalanced zone configuration during an upgrade. However, AKS deletes the surge node(s) once the upgrade has been completed and preserves the original zone balance. If you desire to keep your zones balanced during upgrade, increase the surge to a multiple of three nodes. Virtual machine scale sets will then balance your nodes across Availability Zones with best-effort zone balancing.
+AKS uses best-effort zone balancing in node groups. During an Upgrade surge, zone(s) for the surge node(s) in Virtual Machine Scale Sets is unknown ahead of time. This can temporarily cause an unbalanced zone configuration during an upgrade. However, AKS deletes the surge node(s) once the upgrade has been completed and preserves the original zone balance. If you desire to keep your zones balanced during upgrade, increase the surge to a multiple of three nodes. Virtual Machine Scale Sets will then balance your nodes across Availability Zones with best-effort zone balancing.
 
 If you have PVCs backed by Azure LRS Disks, they’ll be bound to a particular zone, and they may fail to recover immediately if the surge node doesn’t match the zone of the PVC. This could cause downtime on your application when the Upgrade operation continues to drain nodes but the PVs are bound to a zone. To handle this case and maintain high availability, configure a [Pod Disruption Budget](https://kubernetes.io/docs/tasks/run-application/configure-pdb/) on your application. This allows Kubernetes to respect your availability requirements during Upgrade's drain operation.
 
@@ -311,4 +311,4 @@ This article showed you how to upgrade an existing AKS cluster. To learn more ab
 [aks-auto-upgrade]: auto-upgrade-cluster.md
 [release-tracker]: release-tracker.md
 [specific-nodepool]: node-image-upgrade.md#upgrade-a-specific-node-pool
-[k8s-deprecation]: https://kubernetes.io/blog/2022/11/18/upcoming-changes-in-kubernetes-1-26/#:~:text=A%20deprecated%20API%20is%20one%20that%20has%20been,point%20you%20must%20migrate%20to%20using%20the%20replacement
+[k8s-deprecation]: https://kubernetes.io/blog/2022/11/18/upcoming-changes-in-kubernetes-1-26/#:~:text=A%20deprecated%20API%20is%20one%20that%20has%20been,point%20you%20must%20migrate%20to%20using%20the%20replacement