Migrating Terraform state paths to Terragrunt

[JCapriotti]

Hello,
I am investigating Terragrunt by way of converting an existing Terraform structure. Everything is pretty straightforward, except for how to handle a change in the resource names in our remote state file.

For example, each of our existing environment TF folders references a module like this:

module "api" {
  source = "../../module"
}

So in the existing TF state, all the resource names are prefixed with module.api, e.g. module.api.aws_lb_listener_rule.services.

When running terragrunt plan everything is showing up as a destroy + create because of the module above. What was module.api.aws_lb_listener_rule.services in the old Terraform is now aws_lb_listener_rule.services in Terragrunt.

I wasn't able to find a quick way or any guidance for how to handle this. To get past it, I put together a bunch of state mv commands like:

terragrunt state mv module.api.aws_lb_listener_rule.services aws_lb_listener_rule.services

Is there a better way to do this that I missed?

Thanks,
Jason

---

Tracked in ticket #110340

[pras111gw]

Hi @JCapriotti please see: https://github.com/orgs/gruntwork-io/discussions/229

[assiakhateeb]

Hey @pras111gw
I'm encounter this issue while migrating from Terraform to Terragrunt:

  # module.common_helm.helm_release.kube_state_metrics will be destroyed
  # (because helm_release.kube_state_metrics is not in configuration)

Terragrunt renames module.common_helm.helm_release.kube_state_metrics to helm_release.kube_state_metrics after destroying it and creating a new one.

I tried your suggestion and ran the following commands from the directory containing .terragrunt-cache:

terragrunt state pull > state-backup.tfstate 
terragrunt state push state-backup.tfstate

However, the issue wasn't solved in the plan output, and Terragrunt still plans to destroy the resource module.common_helm.helm_release.kube_state_metrics and create helm_release.kube_state_metrics.

Thanks!