SSH Connection Setup

Generate and configure SSH keys for secure GPU instance access.

What Are SSH Keys?

SSH keys are cryptographic key pairs for secure authentication:

Public Key - Uploaded to Spheron AI
Private Key - Kept secure on your machine, never shared

Benefits: Stronger security than passwords, automatic authentication, required for instance access.

Prerequisites

Terminal access (Linux, macOS, or Windows)
Spheron AI account
Basic terminal familiarity

Generate SSH Key

Run ssh-keygen

Linux/Mac:

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

Windows PowerShell:

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

SSH Key Generation

Configure Key

Save location: Press Enter for default (~/.ssh/id_ed25519)
Passphrase: Press Enter twice (none) or set passphrase for extra security

SSH Passphrase

Verify Creation

Output shows:

Your identification has been saved in /Users/yourname/.ssh/id_ed25519
Your public key has been saved in /Users/yourname/.ssh/id_ed25519.pub

Private key: id_ed25519 - Never share
Public key: id_ed25519.pub - Upload to Spheron

Upload to Spheron AI

Method 1: Account Settings (Recommended)

For reusable keys across multiple deployments:

Navigate to Settings

app.spheron.ai → Settings → SSH Keys

SSH Keys Settings

Add Key

Click + Add SSH Key
Enter key name
Paste public key content:

# Display your public key
cat ~/.ssh/id_ed25519.pub

Click Add Key

Method 2: During Deployment

Upload key when deploying instance:

Select Upload New SSH Key option
Choose file or paste public key content
Enter key name
Continue deployment

Connect to Instance

ssh root@your-instance-ip
 
# Or specify key explicitly
ssh -i ~/.ssh/id_ed25519 root@your-instance-ip

Best Practices

✅ Only upload public keys (.pub files)
✅ Never share private keys
✅ Use passphrases for additional security
✅ Rotate keys every 90 days
✅ Use different keys for different services
✅ Backup private keys securely
✅ Delete unused keys

See Security Best Practices for comprehensive guidance.

Troubleshooting

Permission denied:

# Check key is loaded
ssh-add -l
 
# Add key to agent
ssh-add ~/.ssh/id_ed25519
 
# Verify permissions
chmod 600 ~/.ssh/id_ed25519
chmod 644 ~/.ssh/id_ed25519.pub

Wrong key:

Verify correct public key uploaded
Check key fingerprint matches
Try with explicit key: ssh -i ~/.ssh/id_ed25519 user@ip

Connection timeout:

Verify instance is running
Check IP address is correct
Ensure firewall allows SSH (port 22)

Additional Resources

Getting Started - Complete setup guide
User Settings - Manage SSH keys
Security - Security best practices
Quick Start - Fast deployment