I have been searching for a clean way to upgrade the size of nodes within Azure Kubernetes service, which should be straight-forward, but it has not been. There are no blog posts, and it seems when talking with anyone “in the know”, there is little to be done. Microsoft has this on their to-do list, but it is not yet delivered. The only caveat with this adjustment is that if you need to scale-out by attaching more nodes into the cluster, the current tooling in Azure goes back to the initial VM Sizes that were initially set. I would consider this as a quick-patch as part of a larger work-effort in the event that you need additional processing power, you can scale-up while you work on provisioning a new cluster to allow the scale-out.
Chatting with John Goodwin on ddd-cqrs-es slack, he offered me an outline of how to resize a Kerbernetes cluster virtual machine within AKS, and it worked.
When you login to your azure portal, navigate to your Resource Groups, and look for the supporting group that starts with MC_. When you enter the resource group, you will see the list of components that make up the Kubernetes cluster. Within the list, look for the virtual machine(s) that are utilized to power the cluster. Select the virtual machines. The Azure portal should take you to the virtual machine’s dashboard page. From the left-hand side of the dashboard should be an entry for Size. Click on that entry, and select a higher (or lower) size and click Select. This should resize your cluster.
Now, as stated already, please only use these instructions as an intermediary as part of building a new cluster, to service your clients within the interim.
HTH.