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Connecting ROS 2 Nodes with the FASTRTPS_DEFAULT_PROFILES_FILE env

info
  • Level: 🏜️ medium
  • Compatible ROS distributions: ROS 2 Jazzy, ROS 2 Humble, ROS 2 Foxy
  • Compatible RMW implementations: rmw_fastrtps_cpp

You can create a custom DDS configuration file and load it using the FASTRTPS_DEFAULT_PROFILES_FILE environment variable. This file needs to be updated whenever you add a new host to the Husarnet group.

There are many configuration options available, as described in the FastDDS manual.

Examples​

Host Setup​

A basic Husarnet configuration for the Discovery Server and for Simple Discovery (default for DDS) might look like this:

Below is a demonstration using a talker-listener ROS 2 demo. Assume that talker-host and listener-host are Husarnet hostnames of the two devices in the same Husarnet group.

Create the following file on all hosts in the same Husarnet group you wish to connect:

/var/tmp/fastdds-simple.xml
<?xml version="1.0" encoding="UTF-8" ?>
<dds>
    <profiles xmlns="http://www.eprosima.com/XMLSchemas/fastRTPS_Profiles">
        <transport_descriptors>
            <transport_descriptor>
                <transport_id>husarnet_transport</transport_id>
                <type>UDPv6</type>
            </transport_descriptor>
        </transport_descriptors>

        <participant profile_name="husarnet_simple_profile" is_default_profile="true">
            <rtps>
                <userTransports>
                    <transport_id>husarnet_transport</transport_id>
                </userTransports>
                <useBuiltinTransports>true</useBuiltinTransports>
                <defaultUnicastLocatorList>
                    <locator>
                        <udpv6>
                            <address>husarnet-local</address>
                        </udpv6>
                    </locator>
                </defaultUnicastLocatorList>
                <builtin>
                    <initialPeersList>
                <!-- Paste Husarnet Peers here... Start -->
                    <locator>
                        <udpv6>
                            <address>listener-host</address> <!-- or <address>fc94:a67f:2b47:756c:6e1c:7c05:7361:7378</address> -->
                        </udpv6>
                    </locator>
                    <locator>
                        <udpv6>
                            <address>talker-host</address> <!-- or <address>fc94:6260:26e:e057:9bc:8786:4f8a:c7a6</address> -->
                        </udpv6>
                    </locator>
                <!-- End -->
                    </initialPeersList>
                    <metatrafficUnicastLocatorList>
                        <locator>
                            <udpv6>
                                <address>husarnet-local</address>
                            </udpv6>
                        </locator>
                    </metatrafficUnicastLocatorList>
                </builtin>
            </rtps>
        </participant>
    </profiles>
</dds>

Execute the following commands in the terminal:

joe@talker-host
export RMW_IMPLEMENTATION=rmw_fastrtps_cpp
export FASTRTPS_DEFAULT_PROFILES_FILE=/var/tmp/fastdds-simple.xml

ros2 run demo_nodes_cpp talker

Docker Setup​

You can also run the Docker-based demo (both on the same host and different hosts), by running Husarnet within the container:

👉 See the full fastrtps-default-profiles-file (Simple Discovery) example here.

👉 See the full fastrtps-default-profiles-file (Discovery Server) example here.