Providers¶

A provider in Terraform is a plugin that enables interaction with an API. This includes cloud providers, SaaS providers, and other APIs. The providers are specified in the Terraform configuration code. They tell Terraform which services it needs to interact with.

For example, if you want to use Terraform to create a virtual machine on AWS, you would need to use the aws provider. The aws provider provides a set of resources that Terraform can use to create, manage, and destroy virtual machines on AWS.

Here is an example of how to use the aws provider in a Terraform configuration:

provider "aws" {
  region = "us-east-1"
}

resource "aws_instance" "example" {
  ami = "ami-0123456789abcdef0" # Change the AMI 
  instance_type = "t2.micro"
}

In this example, we are first defining the aws provider. We are specifying the region as us-east-1. Then, we are defining the aws_instance resource. We are specifying the AMI ID and the instance type.

When Terraform runs, it will first install the aws provider. Then, it will use the aws provider to create the virtual machine.

Here are some other examples of providers:

azurerm - for Azure
google - for Google Cloud Platform
kubernetes - for Kubernetes
openstack - for OpenStack
vsphere - for VMware vSphere

There are many other providers available, and new ones are being added all the time.

Providers are an essential part of Terraform. They allow Terraform to interact with a wide variety of cloud providers and other APIs. This makes Terraform a very versatile tool that can be used to manage a wide variety of infrastructure.

Different ways to configure providers in terraform¶

There are three main ways to configure providers in Terraform:

In the root module¶

This is the most common way to configure providers. The provider configuration block is placed in the root module of the Terraform configuration. This makes the provider configuration available to all the resources in the configuration.

provider "aws" {
  region = "us-east-1"
}

resource "aws_instance" "example" {
  ami = "ami-0123456789abcdef0"
  instance_type = "t2.micro"
}

In a child module¶

You can also configure providers in a child module. This is useful if you want to reuse the same provider configuration in multiple resources.

module "aws_vpc" {
  source = "./aws_vpc"
  providers = {
    aws = aws.us-west-2
  }
}

resource "aws_instance" "example" {
  ami = "ami-0123456789abcdef0"
  instance_type = "t2.micro"
  depends_on = [module.aws_vpc]
}

In the required_providers block¶

You can also configure providers in the required_providers block. This is useful if you want to make sure that a specific provider version is used.

terraform {
  required_providers {
    aws = {
      source = "hashicorp/aws"
      version = "~> 3.79"
    }
  }
}

resource "aws_instance" "example" {
  ami = "ami-0123456789abcdef0"
  instance_type = "t2.micro"
}

The best way to configure providers depends on your specific needs. If you are only using a single provider, then configuring it in the root module is the simplest option. If you are using multiple providers, or if you want to reuse the same provider configuration in multiple resources, then configuring it in a child module is a good option. And if you want to make sure that a specific provider version is used, then configuring it in the required_providers block is the best option.

Multiple Providers¶

You can use multiple providers in one single terraform project. For example,

Create a providers.tf file in the root directory of your Terraform project.
In the providers.tf file, define the AWS and Azure providers. For example:

provider "aws" {
  region = "us-east-1"
}

provider "azurerm" {
  subscription_id = "your-azure-subscription-id"
  client_id = "your-azure-client-id"
  client_secret = "your-azure-client-secret"
  tenant_id = "your-azure-tenant-id"
}

In your other Terraform configuration files, you can then use the aws and azurerm providers to create resources in AWS and Azure, respectively,

resource "aws_instance" "example" {
  ami = "ami-0123456789abcdef0"
  instance_type = "t2.micro"
}

resource "azurerm_virtual_machine" "example" {
  name = "example-vm"
  location = "eastus"
  size = "Standard_A1"
}

Multiple Region Implementation in Terraform¶

You can make use of alias keyword to implement multi region infrastructure setup in terraform.

provider "aws" {
  alias = "us-east-1"
  region = "us-east-1"
}

provider "aws" {
  alias = "us-west-2"
  region = "us-west-2"
}

resource "aws_instance" "example" {
  ami = "ami-0123456789abcdef0"
  instance_type = "t2.micro"
  provider = "aws.us-east-1"
}

resource "aws_instance" "example2" {
  ami = "ami-0123456789abcdef0"
  instance_type = "t2.micro"
  provider = "aws.us-west-2"
}

Provider Configuration¶

The required_providers block in Terraform is used to declare and specify the required provider configurations for your Terraform module or configuration. It allows you to specify the provider name, source, and version constraints.

terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 3.0"
    }
    azurerm = {
      source  = "hashicorp/azurerm"
      version = ">= 2.0, < 3.0"
    }
  }
}