Adopting Terraform Ephemeral Resources

In version 1.11, HashiCorp introduced Terraform Ephemeral resources and write-only attributes to allow for root configs that do not store secrets in the Terraform statefile. But many users ask about how they can adopt ephemerals. This blog attempts to lay out the ways secrets can be stored in state and how you should update your configurations to remove those secrets. Note: For a primer on ephemerals ( see this blog post ). Scenarios to consider: Data sources that fetch a static secret Resources that receive a secret Resources that generate a dynamic a secret Resources that fetch generated secrets to store in another 3rd party system Scenario 1: Data sources with static secrets Ephemeral resources can often be a drop-in replacement for data sources pulling static values: data "vault_kv_secret_v2" "static_kv" { mount = "kvv2" name = "my_password" } ephemeral "vault_kv_secret_v2" "static_kv" { mount = "kvv2" name = "my_password" } However, using these values has 1 specific difference. The attributes on a ephemeral resource are considered ephemeral and can only be used as ephemeral arguments. That means 2 places: Provider blocks Provider blocks are considered ephemeral, so ephemeral resources may populate arguments: provider "example" { password = tostring ( ephemeral . vault_kv_secret_v2 . static_kv . data . password ) } Write-only arguments Write-only arguments are special arguments that require the ephemeral taint for values: resource "aws_db_instance" "example" { ... password_wo = tostring ( ephemeral . vault_kv_secret_v2 . static_kv . data . password ) } If the resource you wish to pass a value to does not have an available ephemeral, open an issue with that provider. You can reference: this blog post this agent skill Scenario 2: Resources that receive a static secret Without duplicating to the section above, write-only arguments are a way to get secrets out of state. Above has guidance if the secret value comes from a data source, but what if its from a variable?