Export to Terraform

[mikemorris]

It would be great to offer an option to export a cluster configuration to be managed in Terraform, similar to the --target=terraform functionality in kops.

Breaking this out from initial discussion in #132 (comment)

/cc @richardcase @errordeveloper

[errordeveloper]

@mikemorris thanks!

There are a couple of ways this could be achieved, but I'd like to understand the use-cases better.

Short term, the easiest way would be to use CloudFormation+Terraform, i.e. aws_cloudformation_stack. I'd be somewhat more involved, if we wanted to do something similar to what kops does.
However, either way, if you need resource parameters to be passed in via Terraform, it'd would be a big change that I'd rather avoid. I suppose kops doesn't parametrise it's Terraform config, or does it?

However, I would like to make it clear, that long term, the plan is provide to Cluster API support (#19 & #20), which essentially means that instead of terraform apply you'd be able to use eksctl apply or kubectl apply, and instead of HCL config, you'd be looking at Kubernetes API objects essentially.

[TigerC10]

There are a couple of ways this could be achieved, but I'd like to understand the use-cases better.

For one, I think that eksctl is a great starting point for clusters with a lot of configurable options (like installing the WeaveNet cni). For multi-cloud provider setups, terraform is fantastic - so if eksctl could output terraform scripts to be included in a multi-cloud provider project I think we get the best of both worlds.

[errordeveloper]

@TigerC10 thank you, this is quite helpful. Are there any other use-case?

[mikemorris]

My use-case is similar, although our infra is primarily on AWS - eksctl is a great quick setup tool, but we try to follow the "configuration as code" approach, using Terraform to manage all our infrastructure and tracking changes through a git repo (hopefully getting to a "GitOps" flow where changes are deployed by commiting and merging code eventually), would be great to at least be able to output the initial cluster config as Terraform files.

[bingochen87]

Looking eksctl to terraform config file

[Jonathan-7]

there's this project also written in go that supports exporting some AWS TF resources, but not EKS yet unfortunately.
https://github.com/GoogleCloudPlatform/terraformer

[errordeveloper]

Closing in favour of #1094.