In the past I’ve scaled up a cluster to test a new deployment or to provide extra compute during an upgrade but when it comes to scaling down AKS won’t pick the node with less resources or even the drained one so I’ve seen it briefly disrupt a deployment.
To have more control on what AKS scales down you can use virtual machine scale set protection policies to specify which node to remove. Here’s how to do so…
I. Find the node you can to remove and drain it
kubectl drain aks-nodepool-1111111-vmss0001You can verify after
II. Add the protection policy to all nodes except the drained one.
AKS Creates a VMSS for your K8S Nodes you can find AKS’s resource group under Settings –> Properties of your AKS
III. Use AKS to scale down
You will see the node/VM without protection getting removed.
IV. Remove the protection for future upgrades and to allow K8S to Orchestrate
