Vertical scaling of azure kubernetes cluster

5/11/2021

I am unable to scale vertical my AKS cluster. Currently, I have 3 nodes in my cluster with 2 core and 8 ram, I am trying to upgrade it with 16 code and 64 RAM, how do I do it? I tried scaling the VM scale set, on Azure portal it shows it is scaled but when I do "kubectl get nodes -o wide" it still shows the old version.

Any leads will be helpful. Thanks, Abhishek

-- Abhishek Anvekar
azure
azure-aks
azure-vm-scale-set
kubernetes

1 Answer

5/11/2021

Vertical scaling or changing the node pool VM size is not supported. You need to create a new node pool and schedule your pods on the new nodes.

https://github.com/Azure/AKS/issues/1556#issuecomment-615390245

this UX issues is due to how the VMSS is managed by AKS. Since AKS is a managed service, we don't support operations done outside of the AKS API to the infrastructure resources. In this example you are using the VMSS portal to resize, which uses VMSS APIs to resize the resource and as a result has unexpected changes.

AKS nodepools don't support resize in place, so the supported way to do this is to create a new nodepool with a new target and delete the previous one. This needs to be done through the AKS portal UX. This maintains the goal state of the AKS node pool, as at the moment the portal is showing the VMSize AKS knows you have because that is what was originally requested.

-- CSharpRocks
Source: StackOverflow