A few months back I saw that HashiCorp had released a new Kubernetes (K8s) Provider for Terraform, currently in Alpha state, which enable users to deploy K8s resources using the popular Infrastructure-as-Code (IaC) tool. I thought this would be pretty cool if it works with our vSphere with Tanzu solution, since the Tanzu Kubernetes Grid (TKG) Service uses ClusterAPI via a custom VM Operator to deploy TKG Guest Clusters which is just a fancy way of saying it uses K8s API to deploy more K8s 🙂
The setting up the new K8s provider was pretty straight forward and after spending a few minutes in figuring out how to convert my existing TKG YAML to the required HCL format for Terraform to understand, I was able to to run a terraform "plan" but quickly ran into the following error:
failed: admission webhook "default.mutating.tanzukubernetescluster.run.tanzu.vmware.com" does not support dry run
It looks like our tanzukubernetescluster admission webhooks does not currently support dry run operations which can be quite useful but also common when using Terraform. I figured this was the end of that idea and I ended up just filing a feature enhancement internally for adding this support in the future as I can see this being quite useful for our customers.
After finishing up recent pet project of getting a fully functional vSphere with Tanzu on a homelab budget and just using 32GB of memory, I decided to take another look at this and discovered the required tweak to get this working was super trivial, literally a single line change.
Disclaimer: This is not officially supported by VMware, use at your own risk.