Connect Two Sparks

Basic idea

Configure two DGX Spark systems for high-speed inter-node communication using 200GbE direct QSFP connections. This setup enables distributed workloads across multiple DGX Spark nodes by establishing network connectivity and configuring SSH authentication.

What you'll accomplish

You will physically connect two DGX Spark devices with a QSFP cable, configure network interfaces for cluster communication, and establish passwordless SSH between nodes to create a functional distributed computing environment.

What to know before starting

• Basic understanding of distributed computing concepts
• Working with network interface configuration and netplan
• Experience with SSH key management

Prerequisites

• Two DGX Spark systems
• One QSFP cable for direct 200GbE connection between two devices
• SSH access available to both systems
• Root or sudo access on both systems: sudo whoami
• The same username on both systems

Ancillary files

All required files for this playbook can be found here on GitHub

• discover-sparks.sh script for automatic node discovery and SSH key distribution

Time & risk

• Duration: 1 hour including validation

• Risk level: Medium - involves network reconfiguration

• Rollback: Network changes can be reversed by removing netplan configs or IP assignments

• Last Updated: 11/24/2025

  • Minor copyedits