ROS_DOMAIN_ID Change

[yunwool]

Dear Researchers and Developers,

I can see PX4-related ROS 2 messages even without explicitly running any ROS 2 nodes myself.
It looks like these messages are visible under ROS_DOMAIN_ID=0.
Could you please share guidance on how to change the ROS 2 domain ID for these PX4-related messages?

[ApoorvThapliyal]

Hey @yunwool
I would recommend writing export ROS_DOMAIN_ID=1 in your ~/.bashrc and then restarting all terminals so the change takes effect. This should prevent other ROS 2 messages from appearing in your environment, since you’ll effectively be using your own domain.

Optionally, you may want to look into the ROS_LOCALHOST_ONLY variable as well, since I do believe if someone else sets their domain ID to 1, you would see their messages.

[yunwool]

@ApoorvThapliyal
Thank you for the reply.
Did you happen to add export ROS_DOMAIN_ID=1 to your ~/.bashrc?
When I do that, ROS 2 topics disappear in the VOXL shell.
However, on my laptop where ROS_DOMAIN_ID=0, I can see the ROS topics.
That’s why I posted this.

[ApoorvThapliyal]

Hey @yunwool
Did you try setting the ROS_LOCALHOST_ONLY variable to limit the topics to your local device?

[yunwool]

@ApoorvThapliyal
Thank you again for the reply!
We are setting up a multi-robot system, so we are using ROS_LOCALHOST_ONLY=0.
For example, we want to set the ROS_DOMAIN_ID of drone 1 to 1 and the ROS_DOMAIN_ID of drone 2 to 2.
However, for both drones, PX4-related messages still appear under domain ID 0.
Have you tried this with two or more drones?

[ApoorvThapliyal]

Hey @yunwool
Just to be clear, consider only your first drone, if you run export ROS_DOMAIN_ID=1, then run ros2 topic list, you aren't seeing any topics right?

After you set the ROS_DOMAIN_ID of a drone to 1, to get the PX4 topics to show up, on QGC > Analyze Tools > MAVLink Console, run the following commands:

param set XRCE_DDS_DOM_ID 1
param save

Then power cycle the drone, give it like 15s after boot up, then the topics should come up directly when running ros2 topic list on that drone.