Terraform Azure Linux VM Project

Overview

This project provisions a complete Azure environment using Terraform to automate the deployment of a Linux Virtual Machine (VM) with networking, security, and Docker installation. The configuration is designed for reproducibility and compliance with organizational policies, such as requiring a Network Security Group (NSG) on the NIC.

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Tools Used

• Terraform: Infrastructure as Code (IaC) tool for provisioning and managing Azure resources.
• Azure Portal: Occasionally used for manual resource creation and verification.
• Azure CLI: Used for authentication (az login) and resource inspection.
• VS Code: Editor for writing and managing Terraform and shell/cloud-init scripts.
• SSH: For connecting to the provisioned VM.

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What This Project Does

1. Creates an Azure Resource Group (mtc-resources) in the East US region.
2. Creates a Virtual Network (mtc-network) and a Subnet (mtc-subnet).
3. Creates a Network Security Group (mtc-sg) with an inbound rule (mtc-dev-rule) allowing all traffic (for demo/dev purposes).
4. Associates the NSG with the Subnet to comply with Azure policy.
5. Creates a Public IP Address (mtc-ip) with Basic SKU and Dynamic allocation.
6. Creates a Network Interface (mtc-nic) attached to the subnet and public IP, with the required NSG association.
7. Creates a Linux Virtual Machine (mtc-vm) using an Ubuntu 20.04 LTS image, with SSH key authentication.
8. Bootstraps the VM with Docker using a custom data script (customdata.tpl).
9. Configures local SSH using a template (mac-ssh-script.tpl) for easy access.
10. Outputs the VM's public IP address for quick connection.

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Key Files

• main.tf: Main Terraform configuration for all Azure resources.
• variables.tf: Defines input variables (e.g., host_os).
• customdata.tpl: Bash script for installing Docker on the VM at boot.
• mac-ssh-script.tpl: Template for updating your local SSH config.
• terraform.tfstate: Terraform state file (do not edit manually).

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Steps Performed

1. Terraform Initialization and Authentication

   • Ran terraform init to initialize the project.
   • Logged in to Azure using az login and set the correct subscription.

2. Resource Creation

   • Defined all resources in main.tf.
   • Used terraform apply to provision resources.
   • When Azure policy required an NSG on the NIC at creation, either:
     • Upgraded the AzureRM provider to v3.x+ to use network_security_group_id (if possible), or
     • Created the NIC in the Azure Portal and imported it with terraform import.

3. Manual Steps (if needed)

   • Created and configured the NIC in the Azure Portal when policy blocked Terraform-only creation.
   • Associated the public IP and NSG with the NIC via the portal UI.
   • Imported manually created resources into Terraform state.

4. VM Provisioning

   • Used a custom data script (customdata.tpl) to install Docker automatically on the VM.
   • Verified Docker installation by SSH-ing into the VM.

5. SSH Configuration

   • Used a template (mac-ssh-script.tpl) to update the local SSH config for easy access to the VM.

6. Output

   • Used a Terraform output to display the VM name and public IP after deployment.

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Troubleshooting & Lessons Learned

• Azure Policy Enforcement: Some policies require NSG attachment at NIC creation, which may require provider upgrades or manual steps.
• Provider Version Compatibility: Features like network_security_group_id on NICs require AzureRM provider v3.x+.
• Resource Importing: Manual Azure Portal resources can be imported into Terraform state for continued management.
• Dynamic Public IPs: Azure only allocates a dynamic public IP after the VM is running and the NIC is attached.
• Custom Data Scripts: Ensure correct syntax and permissions for successful VM bootstrapping.

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How to Use

1. Clone the repository and navigate to the project directory.
2. Run terraform init to initialize.
3. Run az login to authenticate with Azure.
4. Run terraform apply to provision resources.
5. Use the outputted public IP to SSH into your VM.

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Cleanup

To destroy all resources:

terraform destroy

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References

• Terraform Azure Provider Documentation
• Azure Portal
• Azure CLI Documentation
• Cloud-init Documentation
• Learn Terraform with Azure by Building a Dev Environment

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