TFNFR27 - Provider Declarations in Modules

By rules , in the module code provider MUST NOT be declared. The only exception is when the module indeed need different instances of the same kind of provider(Eg. manipulating resources across different locations or accounts), you MUST declare configuration_aliases in terraform.required_providers. See details in this document .

provider block declared in the module MUST only be used to differentiate instances used in resource and data. Declaration of fields other than alias in provider block is strictly forbidden. It could lead to module users unable to utilize count, for_each or depends_on. Configurations of the provider instance SHOULD be passed in by the module users.

Good examples:

In verified module:

terraform {
  required_providers {
    azurerm = {
      source  = "hashicorp/azurerm"
      version = "~> 3.0"
      configuration_aliases = [ azurerm.alternate ]
    }
  }
}

In the root module where we call this verified module:

provider "azurerm" {
  features {}
}

provider "azurerm" {
  alias = "alternate"
  features {}
}

module "foo" {
  source = "xxx"
  providers = {
    azurerm = azurerm
    azurerm.alternate = azurerm.alternate
  }
}

Bad example:

In verified module:

provider "azurerm" {
  # Configuration options
  features {}
}