Hi can I have a custom script to be executed in AKS node group?

1
votes

I would like to tweak some settings in AKS node group with something like userdata in AWS. Is it possible to do in AKS?

how abt using

https://registry.terraform.io/providers/hashicorp/azurerm/latest/docs/resources/virtual_machine_scale_set_extension

1
azureazure-aksuser-data
You created the cluster using terraform? the node pool is Linux or Windows? do you have any autoscalling? - Amit Baranes
terraform, node pool is linux. Yes autoscaling is there - cloudbud

1 Answers

2
votes

The underlying Virtual Machine Scale Set (VMSS) is an implementation detail, and one that you do not get to adjust outside of SKU and disk choice. Just like you cannot pick the image that goes on the VMSS; you also cannot use VM Extensions on that scale set, without being out of support. Any direct manipulation of those VMSSs (from an Azure resource provider perspective) behind your nodepools puts you out of support. The only supported affordance to perform host (node)-level actions is via deploying your custom script work in a DaemonSet to the cluster. This is fully supported, and will give you the ability to run (almost) anything you need at the host level. Examples being installing/executing custom security agents, FIM solutions, anti-virus.

From the support FAQ:

Any modification done directly to the agent nodes using any of the IaaS APIs renders the cluster unsupportable. Any modification done to the agent nodes must be done using kubernetes-native mechanisms such as Daemon Sets.