2. Providers

A Terraform Provider is a plugin which will communicate with a service API for resource configuration. For example, in order to configure Azure resources Terraform uses the azurerm provider. Providers are usually written by the organization that provides the product being configured, though that is not always the case. For example, the BIG-IP is provided by F5, but the Azure provider is provided directly by Hashicorp (the same company that created Terraform). Terraform providers are downloaded and installed during the terraform init stage of the workflow.

There are two sections of a provider. The first section declares that a provider is required, and the second section is the provider configuration.

1. Declaration

   The ‘terraform’ block is not limited on only one Provider; more can be defined depending on what your Terraform Run requires. Here are a few example Provider configurations:

   terraform {
     required_providers {
       azurerm = { version = "3.14.0" }
     }
   }
   

2. Configuration

Azure

Note

Along with identifying and downloading the Provider, terraform init will also upgrade the provider if a newer one is available and the specific version isn’t specified in the provider declaration. The example above defines the specific version of the provider to be used, and newer versions will be ignored. A version statement ‘version ~> “3.14.0”, may be used to specify an upgrade whenever a new version is available. If the newer version includes changes to the options/arguments in any of the resources, a refactor of the configuration may be required to suit the newer version, so it is best practice to restrict the provider to a specific version to control the upgrade.

The Provider configuration blocks define changes to the default provider behavior. Even without any changes each provider must still have a configuration block. Here is a default configuration block for the Azure Provider:

provider "azurerm" { }

Provider configuration blocks can be much more complicated. Here is a configuration block for the Azure subscriber that includes a few modifications to the default behavior:

provider "azurerm" {
  features {
    virtual_machine {
      # Necessary for license revocation when using BIG-IQ LM.
      graceful_shutdown                       = true
      delete_os_disk_on_deletion              = true
    }
    template_deployment {
      #  Allow the RG to be removed even if resources are still present
      delete_nested_items_during_deletion     = true
    }
    resource_group {
      # Allow the RG to be removed even if resources are still present
      prevent_deletion_if_contains_resources  = false
    }
  }
}

AWS

The Terraform AWS Provider configuration block shown here pulls the credentials and profile from local values (variables), and defines the default region for operations.

terraform {
  required_providers {
    aws = {
      source = "hashicorp/aws"
      version = "~> 3.0"
    }
  }
}

provider "aws" {
  shared_credentials_file   = local.creds_file
  profile                   = local.profile
  region                    = var.region
}

Notice that even the terraform configuration block differs from the Azure example. In this case the source of the provider is defined in addition to what version of the provider should be used.

GCP

And finally, the GCP Provider.

terraform {
  required_providers {
    google = {
      version = "4.40.0"
    }
  }
}

provider "google" {
  project                   = var.project
  region                    = var.region
  zone                      = var.zone
}