ROS2-WSL2-CycloneDDS-setup.md

Since communication over ROS2 across WSL2 border doesn't work out of the box, here's my notes for getting it to work.

Make sure to select cyclonedds RMW on both ends:

(Linux)

export RMW_IMPLEMENTATION=rmw_cyclonedds_cpp

(Windows)

set RMW_IMPLEMENTATION=rmw_cyclonedds_cpp

If it complains that RMW implementation is not installed, install it with sudo apt install ros-humble-cyclonedds ros-humble-rmw-cyclonedds-cpp.

Additionally, on Windows, due to the presence of many (virtual) network interface, we have to tell CycloneDDS to use the correct one:

<?xml version="1.0" encoding="UTF-8" ?>
<CycloneDDS xmlns="https://cdds.io/config" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="https://cdds.io/config https://raw.githubusercontent.com/eclipse-cyclonedds/cyclonedds/master/etc/cyclonedds.xsd">
  <Domain id="any">
    <General>
        <Interfaces>
            <NetworkInterface name="vEthernet (WSL)" />
        </Interfaces>
    </General>
  </Domain>
</CycloneDDS>

Save the above to a file, and point it to the CYCLONEDDS_URI variable, e.g.:

set CYCLONEDDS_URI=c:/CycloneDDS/wsl2.xml