Setting Up a Multi-Cloud Infrastructure with Terraform on AWS and Azure

In today's cloud-driven world, organizations are increasingly adopting multi-cloud strategies to leverage the unique strengths of different cloud service providers. By setting up a multi-cloud infrastructure, businesses can enhance their flexibility, improve disaster recovery, and optimize costs. This article will walk you through the process of creating a multi-cloud infrastructure using Terraform, focusing on AWS and Azure. You'll find clear code examples, step-by-step instructions, and actionable insights to help you get started.

What is Multi-Cloud Infrastructure?

Multi-cloud infrastructure refers to the use of multiple cloud computing services in a single architecture. Instead of relying solely on one provider, organizations can distribute workloads across different platforms—such as AWS and Azure—to achieve greater efficiency and resilience.

Benefits of Multi-Cloud

• Flexibility: Choose services from different providers based on specific needs.
• Avoid Vendor Lock-In: Mitigate risks associated with being dependent on a single vendor.
• Cost Optimization: Take advantage of competitive pricing models.
• Enhanced Disaster Recovery: Implement robust backup solutions across clouds.

Getting Started with Terraform

Terraform is an open-source infrastructure as code (IaC) tool developed by HashiCorp. It allows you to define and provision data center infrastructure using a declarative configuration language. Terraform supports various cloud service providers, including AWS and Azure, making it a perfect tool for setting up a multi-cloud infrastructure.

Prerequisites

Before diving into the code, ensure you have the following:

• A Terraform installation (version 0.12 or later).
• AWS and Azure accounts.
• AWS CLI and Azure CLI installed and configured on your local machine.
• Basic understanding of Terraform syntax and cloud services.

Step-by-Step Guide to Setting Up Multi-Cloud Infrastructure

Step 1: Create the Terraform Configuration File

Start by creating a directory for your project and a file named main.tf. This file will contain the configuration for both AWS and Azure.

mkdir multi-cloud-infrastructure
cd multi-cloud-infrastructure
touch main.tf

Step 2: Provider Configuration

In your main.tf, define the AWS and Azure providers. This is where you specify the credentials and regions for each cloud provider.

# Specify the required providers
terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 3.0"
    }
    azurerm = {
      source  = "hashicorp/azurerm"
      version = "~> 2.0"
    }
  }
}

# Configure AWS provider
provider "aws" {
  region = "us-west-2"
}

# Configure Azure provider
provider "azurerm" {
  features {}
}

Step 3: Define Resources on AWS

Next, let's create a simple AWS EC2 instance. This instance will serve as a web server.

resource "aws_instance" "web_server" {
  ami           = "ami-12345678"  # Replace with a valid AMI ID in your region
  instance_type = "t2.micro"

  tags = {
    Name = "AWS Web Server"
  }
}

Step 4: Define Resources on Azure

Now, let’s create an Azure Virtual Machine. Similar to the AWS EC2 instance, this VM will also function as a web server.

resource "azurerm_resource_group" "example" {
  name     = "example-resources"
  location = "West US"
}

resource "azurerm_virtual_network" "example" {
  name                = "example-network"
  address_space       = ["10.0.0.0/16"]
  location            = azurerm_resource_group.example.location
  resource_group_name = azurerm_resource_group.example.name
}

resource "azurerm_subnet" "example" {
  name                 = "example-subnet"
  resource_group_name  = azurerm_resource_group.example.name
  virtual_network_name = azurerm_virtual_network.example.name
  address_prefixes     = ["10.0.1.0/24"]
}

resource "azurerm_network_interface" "example" {
  name                = "example-nic"
  location            = azurerm_resource_group.example.location
  resource_group_name = azurerm_resource_group.example.name

  ip_configuration {
    name                          = "example-ip-config"
    subnet_id                     = azurerm_subnet.example.id
    private_ip_address_allocation = "Dynamic"
  }
}

resource "azurerm_linux_virtual_machine" "example" {
  name                = "example-machine"
  resource_group_name = azurerm_resource_group.example.name
  location            = azurerm_resource_group.example.location
  size                = "Standard_DS1_v2"
  admin_username      = "adminuser"
  admin_password      = "P@ssword1234"  # Use a secure password
  network_interface_ids = [azurerm_network_interface.example.id]

  os_disk {
    caching              = "ReadWrite"
    create_option        = "FromImage"
  }

  source_image_reference {
    publisher = "Canonical"
    offer     = "UbuntuServer"
    sku       = "18.04-LTS"
    version   = "latest"
  }
}

Step 5: Initialize Terraform and Apply Configuration

Now that you have defined your infrastructure, it’s time to initialize Terraform and apply the configuration.

1. Initialize Terraform: bash terraform init

2. Apply the Configuration: bash terraform apply

Confirm the action by typing yes. Terraform will provision your resources on both AWS and Azure.

Step 6: Verify the Resources

After the apply process is complete, you can verify the resources in both the AWS Management Console and the Azure Portal. You should see your EC2 instance in AWS and the virtual machine in Azure.

Troubleshooting Common Issues

• Authentication Issues: Ensure that the AWS CLI and Azure CLI are configured correctly with the right credentials.
• Resource Limitations: Be aware of the limits on free tiers for both AWS and Azure to avoid unexpected charges.
• Network Configuration: Ensure that your network settings, such as security groups and firewalls, allow traffic between your instances.

Conclusion

Setting up a multi-cloud infrastructure using Terraform allows organizations to harness the power of both AWS and Azure effectively. By following this guide, you can create a robust, flexible, and cost-effective cloud environment tailored to your needs. Whether you're running a web application or a complex enterprise solution, multi-cloud architecture can provide the scalability and reliability you require. Happy coding!