Terraform FCK-NAT High Availability

This project deploys a cost-effective, self-healing NAT solution on AWS using fck-nat instances within an Auto Scaling Group. It includes a Justfile to automate deployment and simplify SSH connections to private resources.

Features

• Cost Effective: Uses t4g.nano or t3.micro instances instead of expensive AWS NAT Gateways.
• Self-Healing: If the NAT instance fails, the Auto Scaling Group launches a new one, and the route table is automatically updated.
• Automation: Includes a Justfile for one-command deployment and SSH tunneling.
• VS Code Support: Pre-configured tasks for easy execution from the editor.

Prerequisites

1. Terraform installed.
2. AWS CLI configured with credentials.
3. Just installed (command runner).

Quick Start

The project uses just to handle Terraform commands and key permissions automatically.

1. Initialize and Deploy

just init
just apply

2. View Info

Displays the generated keys and IP addresses.

just info

Connecting to Instances

This setup includes helper commands to handle SSH keys and tunneling automatically.

Connect to the NAT Instance (Public)

Connects directly to the bastion/NAT host.

just ssh-nat

Connect to the Private App

Since the application server is in a private subnet, we use SSH tunneling.

1. Open the tunnel in the background:

   just ssh-tunnel

2. Connect to the app:

   just ssh-app

3. Close the tunnel when finished:

   just ssh-tunnel-close

VS Code Integration

A .vscode/tasks.json file is included. You can run all the above commands directly from Visual Studio Code:

1. Press Ctrl+Shift+P (or Cmd+Shift+P on Mac).
2. Type Run Task.
3. Select any task (e.g., ⚡ Terraform Apply, 💻 SSH to Private App).

Clean Up

To destroy all resources:

just destroy

Troubleshooting

• Key Permission Error: Run just fix-perms.
• Host Key Verification Failed: Run just ssh-clear to remove old localhost entries from your known_hosts file.
• Tunnel Issues: Run just ssh-tunnel-close to clear old processes, then try opening the tunnel again.