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SSH Connection Guide

Connect to your rented GPU with full root access

Overview

When you rent a GPU on CapaCloud, you get full root access to the machine. This guide will help you connect and start using your rented GPU.

Getting Your Connection Details

  1. Go to your rental details page (from My Rentals)
  2. Find the "Connect to Machine" section
  3. You'll see:
    • SSH Host (IP address or hostname)
    • SSH Port
    • SSH Username (usually "root")
    • SSH connection command (template with your key path)

Note: You'll need to have added SSH keys to your account settings before renting.

Connecting via SSH

Step 1: Add Your SSH Key to Your Account

Before renting a machine, you need to add at least one SSH public key to your account:

  1. Go to Account Settings
  2. Navigate to the "SSH Keys" section
  3. Click "Add SSH Key"
  4. Enter a name for your key (e.g., "My Laptop")
  5. Paste your SSH public key (usually from ~/.ssh/id_rsa.pub or ~/.ssh/id_ed25519.pub)
  6. Click "Add Key"

Step 2: Select SSH Keys When Renting

When you rent a machine, you'll be prompted to select which SSH keys to use. You can select one or more keys. These keys will be automatically registered to the machine.

Step 3: Connect Using Your Private Key

Use the SSH command from your rental details page. Replace ~/.ssh/your_keywith the path to your private key:

ssh -i ~/.ssh/id_rsa root@hostname -p port

Or if you use a different key:

ssh -i ~/.ssh/id_ed25519 root@hostname -p port

Note: Make sure your private key has correct permissions: chmod 600 ~/.ssh/id_rsa

Using SSH on Different Systems

Linux / macOS

Use the terminal and SSH command directly. Most systems have SSH pre-installed.

Windows

You can use:

  • •PowerShell: Built-in SSH client (Windows 10+)
  • •Windows Terminal: Modern terminal with SSH support
  • •PuTTY: Traditional SSH client
  • •WSL: Windows Subsystem for Linux

Managing SSH Keys

Adding Multiple Keys

You can add multiple SSH keys to your account. This is useful if you want to access rented machines from different devices (laptop, desktop, etc.). Each key should have a descriptive name.

Changing Keys for Active Rentals

You can change which SSH keys are registered to an active rental:

  1. Go to your rental details page
  2. Scroll to the "SSH Keys for This Rental" section
  3. Click "Change Keys"
  4. Select the keys you want to use
  5. Click "Update Keys"

Changes are applied immediately. You can use the new keys right away.

Generating SSH Keys

If you don't have an SSH key pair yet, you can generate one:

For Ed25519 (Recommended):

ssh-keygen -t ed25519 -C "your_email@example.com"

For RSA (if Ed25519 not supported):

ssh-keygen -t rsa -b 4096 -C "your_email@example.com"

Your public key will be saved at ~/.ssh/id_ed25519.pub (or ~/.ssh/id_rsa.pub). Copy this file's contents and add it to your account settings.

Verifying GPU Access

Once connected, verify GPU access:

nvidia-smi

This should display your GPU information, utilization, and memory usage.

Troubleshooting

Connection Refused

  • • Verify the SSH port is correct
  • • Check that the rental is still active
  • • Ensure your firewall allows SSH connections

Permission Denied

  • • Verify SSH key permissions (should be 600): chmod 600 ~/.ssh/your_key
  • • Make sure you're using the private key that corresponds to the public key in your account
  • • Check that your public key is registered to the rental (check rental details page)
  • • Verify the username is correct (usually "root")

Key Not Registered

  • • Make sure you selected at least one SSH key when renting the machine
  • • Check that your key is in your account settings
  • • Wait up to 1 minute for the worker to register keys (worker polls every minute)
  • • Try changing keys on the rental details page to trigger immediate update

For more help, see Troubleshooting Guide.