Using GMAB to Manage Temporary Hetzner Cloud Instances

Introduction

Sometimes you need a quick cloud server for a temporary task - maybe for testing from a different IP address, running a short computational job, or setting up a temporary development environment. Manually creating and managing these temporary servers through cloud provider UIs can become tedious and error-prone.

This is where GMAB (Give Me A Box) comes in. GMAB is a command-line tool that makes it easy to spawn, manage, and clean up temporary cloud instances across multiple providers, including Hetzner Cloud. The tool is particularly useful for:

• Bug bounty hunting from different IP addresses
• Web scraping or testing from various regions
• Running temporary workloads without manual cleanup
• Development environments that don't need to persist
• Quick access to computational resources in different geographic locations

In this tutorial, we'll focus on using GMAB with Hetzner Cloud, covering everything from installation and configuration to daily usage patterns.

Prerequisites

Before getting started with GMAB, you'll need:

• Local machine:
  • Python 3.7 or higher installed
  • Pip (Python package manager)
  • An SSH key pair (ed25519 recommended)

• A Hetzner Cloud account

Step 1 - Installing GMAB

GMAB can be installed directly from PyPI (Python Package Index) using pip. Open your terminal and run one of the following commands:

For a system-wide installation:

pip install gmab

For a user-specific installation (without admin privileges):

pip install --user gmab

After installation, verify that GMAB installed correctly:

gmab --help

You should see the help menu displaying the available commands and options.

Step 2 - Setting Up Hetzner Cloud Project and API Token

Before configuring GMAB, you need to set up Hetzner Cloud appropriately by creating a dedicated project and generating an API token.

Creating a Dedicated Project

1. Log in to your Hetzner Cloud Console at console.hetzner.cloud

2. Click the + New project button:

   

3. Name your project gmab (or another name of your choice)

   

4. Click Add project to create and switch to the new project.

Generating an API Token

Now that you have a project, you can generate the API token as explained in the official documentation: Generating an API token

Step 3 - Configuring GMAB

Now that you have your Hetzner Cloud project and API token, you can configure GMAB for use with Hetzner Cloud.

Initial Configuration

Run the configuration wizard:

gmab configure

The tool will guide you through an interactive configuration process. When prompted to configure Hetzner, select "y" and enter your API token:

$ gmab configure
Using config directory: /home/user/.config/gmab

Configuring general settings:
SSH public key path [~/.ssh/id_ed25519.pub]: 
Default instance lifetime (minutes) [60]: 
Default provider (linode, aws, hetzner) [linode]: hetzner

Do you want to configure linode? [Y/n]: n

Do you want to configure aws? [Y/n]: n

Do you want to configure hetzner? [Y/n]: y

Configuring hetzner provider:
API Key: your-hetzner-api-token-here
Default region [nbg1]: 
Default image [ubuntu-22.04]: ubuntu-24.04
Default instance type [cpx11]: 

Configuration completed successfully!

Understanding Configuration Options

During configuration, you'll have several options to customize:

Step 4 - Creating Your First Instance

Now that GMAB is configured, let's create your first Hetzner Cloud instance.

Basic Instance Creation

To spawn a Hetzner Cloud instance using your default settings:

gmab spawn

If Hetzner is not your default provider, specify it with the -p flag:

gmab spawn -p hetzner

You'll see output similar to this:

Spawned 'hetzner' instance:
  ID: 12345678
  Label: gmab-abc123def456
  IP: 192.168.1.100
  Connect via: ssh root@192.168.1.100

Customizing Your Instance

GMAB allows you to override defaults when spawning an instance:

# Specify a different region
gmab spawn -p hetzner -r hel1

# Specify a different image
gmab spawn -p hetzner -i ubuntu-24.04

# Specify instance lifetime (in minutes)
gmab spawn -p hetzner -t 120  # 2 hour lifetime

# Combine options
gmab spawn -p hetzner -r fsn1 -i debian-12 -t 180

Connecting to Your Instance

Once the instance is running, connect to it using SSH:

ssh root@<ip_address>

Replace <ip_address> with the IP address shown in the spawn output.

Step 5 - Managing Your Instances

GMAB provides commands to help you manage your temporary instances.

Listing All Instances

To view all your active Hetzner instances:

gmab list -p hetzner

Example output:

Provider    Instance ID     Label                IP Address       Status              Region    Image              Time Left
=============================================================================================================
hetzner     12345678        gmab-abc123def456    192.168.1.100    running             nbg1       ubuntu-24.04      45m
hetzner     98765432        gmab-ghi789jkl012    10.0.0.100       running             hel1       ubuntu-24.04      15m
hetzner     56781234        gmab-mno345pqr678    10.0.2.200       running (expired)   fsn1       debian-12         expired

The Time Left column shows how much time remains before the instance is considered expired.

Understanding the Expiration Mechanism

A key feature of GMAB is its expiration mechanism. Here's how it works:

1. When you spawn an instance, you specify a lifetime in minutes (default is 60)
2. GMAB tracks this lifetime and marks instances as "expired" once the time is up
3. Important: GMAB does NOT automatically delete expired instances
4. You must explicitly run a command to delete expired instances

This design gives you control over when instances are actually deleted, preventing unexpected disruptions while you're still using them.

Deleting Instances

To delete a specific instance:

gmab terminate 12345678  # Using Instance ID

Or:

gmab terminate gmab-abc123def456  # Using Label

To delete multiple instances at once:

gmab terminate 12345678 98765432

Deleting All Instances

To delete all your Hetzner instances:

gmab terminate all -p hetzner

You'll be prompted for confirmation:

The following instances will be terminated:
- 12345678 (hetzner: gmab-abc123def456)
- 98765432 (hetzner: gmab-ghi789jkl012)
- 56781234 (hetzner: gmab-mno345pqr678)
Do you want to proceed? [y/N]: 

Deleting Expired Instances

The most common cleanup task is deleting expired instances:

gmab terminate expired -p hetzner

Again, you'll see a confirmation prompt:

The following expired instances will be terminated:
- 56781234 (hetzner: gmab-mno345pqr678)
Do you want to proceed? [y/N]: 

Using the -y Flag for Automated Cleanup

For scripts or automated tasks, you can use the -y flag to bypass confirmation prompts:

gmab terminate expired -p hetzner -y

This is particularly useful for scheduled cleanup jobs, as we'll see in the next section.

Step 6 - Automating Cleanup

Since GMAB doesn't automatically delete expired instances, you can set up scheduled cleanup to avoid unnecessary costs.

Setting up a Cron Job (Linux/macOS)

1. Open your crontab file:

   crontab -e

2. Add a line to run the cleanup command regularly:

   # Clean up expired instances every hour
   0 * * * * gmab terminate expired -y

   This will run every hour on the hour. For less frequent cleanup:

   # Run daily at midnight
   0 0 * * * gmab terminate expired -y

Using Windows Task Scheduler

On Windows, you can use Task Scheduler:

1. Create a batch file (e.g., gmab-cleanup.bat) with the following content:

   @echo off
   gmab terminate expired -y

2. Open Task Scheduler and create a new basic task

3. Set the task to run on a schedule (e.g., daily or hourly)

4. Point the action to your batch file

Step 7 - Practical Use Case Examples

Here are some practical examples of using GMAB with Hetzner Cloud.

• Example 1: Quick Security Testing

  Need to run a security scan from an external IP?

  # Create a box with 30 minute lifetime
  gmab spawn -p hetzner -t 30
  
  # SSH into the box
  ssh root@<ip-address>
  
  # Run your security tools
  # ...
  
  # When done, delete the instance
  gmab terminate <instance-id>

• Example 2: Region-Specific Testing

  Test how your website appears from different regions:

  # Create instances in different regions
  gmab spawn -p hetzner -r nbg1 -t 60
  gmab spawn -p hetzner -r hel1 -t 60
  gmab spawn -p hetzner -r ash -t 60
  
  # Run your tests from each instance
  # ...
  
  # Clean up when finished
  gmab terminate all -p hetzner -y

• Example 3: Running Cron Jobs or Scheduled Tasks

  Use GMAB to run regular jobs using cron (Linux) or scheduled tasks (Windows) without keeping your local machine turned on:

  # Create a box with longer lifetime
  gmab spawn -p hetzner -t 1440  # 24 hours
  
  # Connect to the instance
  ssh root@<ip-address>
  
  # Set up a cron job (Linux)
  # Example: crontab -e
  # 0 */4 * * * /path/to/script.sh
  
  # Or set up a scheduled task on Windows Server
  # ...
  
  # Manually delete when tasks are complete
  gmab terminate <instance-id>

Troubleshooting

Common issues:

Best Practices

Conclusion

GMAB with Hetzner Cloud provides an efficient way to deploy temporary instances for various use cases. The expiration mechanism helps you keep track of resources without forcing immediate deletion, giving you flexibility while helping to avoid unexpected costs.

Key takeaways:

• Instances are marked as "expired" after their lifetime elapses but continue running
• You must explicitly delete instances with gmab terminate
• The -y flag skips confirmation prompts, useful for automated cleanup
• Setting up a cron job for regular cleanup is highly recommended

With this knowledge, you can efficiently use GMAB to manage temporary Hetzner Cloud instances for your projects, tests, and workflows.

License: MIT