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Multi-Machine Communication Setup

After installing Ubuntu VM on your host PC, the next step is to configure multi-machine communication between your host VM and the Jetson Nano. This allows your development computer to interact with the JetRacer remotely.

Overview​

ROS (Robot Operating System) is designed to work across multiple machines, allowing you to:

  • Run resource-intensive computations on your more powerful host PC
  • Control the JetRacer remotely
  • Visualize sensor data and debug information on your development machine
  • Deploy code seamlessly between development and robot environments

In this guide, you'll learn how to:

  1. Configure network settings on both machines
  2. Set up ROS environment variables
  3. Test the multi-machine communication
  4. Troubleshoot common issues

Prerequisites​

  • Jetson Nano with ROS installed and connected to your network
  • Ubuntu VM running on your host PC
  • Both machines connected to the same network

Step 1: Determine IP Addresses​

First, you need to know the IP addresses of both machines:

On Jetson Nano:​

Look at the OLED display of the mainboard to see the IP (e.g., 192.168.1.100).

On Ubuntu VM:​

ifconfig

Look for the ens33 or similar interface and note the IP address (e.g., 192.168.1.200).

Step 2: Configure Hosts File on Both Machines​

You'll need to edit the hosts file on both machines to enable hostname resolution:

On Jetson Nano:​

sudo nano /etc/hosts

Add the following lines:

127.0.0.1       localhost
127.0.1.1       jetson
192.168.1.100   jetson    # Your Jetson Nano's IP
192.168.1.200   ubuntu    # Your Ubuntu VM's IP

Save and exit (Ctrl+X, then Y, then Enter).

On Ubuntu VM:​

sudo nano /etc/hosts

Add the following lines:

127.0.0.1       localhost
127.0.1.1       ubuntu
192.168.1.100   jetson    # Your Jetson Nano's IP
192.168.1.200   ubuntu    # Your Ubuntu VM's IP

Save and exit.

Step 3: Configure ROS Environment Variables​

ROS needs to know which machine is the master and how to communicate between machines:

On Jetson Nano (ROS Master):​

Edit the .bashrc file:

nano ~/.bashrc

Add these lines at the end:

export ROS_MASTER_URI=http://jetson:11311
export ROS_HOSTNAME=jetson

Apply the changes:

source ~/.bashrc

On Ubuntu VM:​

Edit the .bashrc file:

nano ~/.bashrc

Add these lines at the end:

export ROS_MASTER_URI=http://jetson:11311
export ROS_HOSTNAME=ubuntu

Apply the changes:

source ~/.bashrc

Step 4: Test the Communication​

Now let's test if the multi-machine communication is working:

On Jetson Nano:​

Start the ROS master:

roscore

On Ubuntu VM:​

Check if you can see the ROS master:

rostopic list

If you see a list of topics (even if it's just /rosout and /rosout_agg), the communication is working!

Step 5: Run a Test Example​

Let's run a simple publisher/subscriber example to verify the communication:

On Jetson Nano:​

Start an example receiving node:

rosrun rospy_tutorials listener

On Ubuntu VM:​

Start an publishing receiving node:

rosrun rospy_tutorials talker

You should see "hello world" messages appearing repeatedly being received on the Jetson side.

Troubleshooting​

Cannot Connect to ROS Master​

  1. Verify both machines can ping each other:

    ping jetson  # From Ubuntu VM
    ping ubuntu  # From Jetson Nano

  2. Verify ROS environment variables:

    echo $ROS_MASTER_URI
    echo $ROS_HOSTNAME

Connection Timeouts​

  1. Make sure both machines are on the same network
  2. Check if the IP addresses have changed (common with DHCP)
  3. Update the hosts file if IP addresses change

References​

For more detailed instructions, refer to the official Waveshare JetRacer ROS AI Kit Tutorial IV.