1.1.1. Easy Mode Tutorial

This tutorial aims to demonstrate the new Easy Mode feature in Vulcanexus by running a simple talker-listener example demo.

1.1.1.1. Prerequisites

1.1.1.2. Preparation

Lets start by setting up the Vulcanexus environment. First, create an isolated Docker network for the Vulcanexus containers:

docker network create --subnet=172.18.0.0/16 vulcanexus_net

Run two containers of the Vulcanexus Docker image and source the Vulcanexus installation with:

# Terminal 1
docker run --net vulcanexus_net --ip 172.18.0.2 -it --rm ubuntu-vulcanexus:jazzy-desktop
source /opt/vulcanexus/jazzy/setup.bash

# Terminal 2
docker run --net vulcanexus_net --ip 172.18.0.3 -it --rm ubuntu-vulcanexus:jazzy-desktop
source /opt/vulcanexus/jazzy/setup.bash

Note

It is also possible to run the tutorial between two hosts sharing the same network.

1.1.1.3. Running the demo

The tutorial consists in two docker containers (hosts) running a ROS 2 talker - listener example with the new Vulcanexus Easy Mode enabled. Both hosts are in the same network and domain id as shown in the following diagram:

../../../../../_images/easy_mode_tutorial.png

Discovery server in Host A will serve as the master server. Hence, the IP address of Host A will be used to enable the Easy Mode in both containers. Run the following commands in each container:

# Container 1
ROS2_EASY_MODE=172.18.0.2 ros2 run demo_nodes_cpp talker

# Container 2
ROS2_EASY_MODE=172.18.0.2 ros2 run demo_nodes_cpp listener

Note

If the tutorial is run using two hosts, the IP address of the ROS2_EASY_MODE environment variable needs to be set to the IP address of the first host. It is also possible to run the demo in a single host by opening two terminals and running the commands in each terminal. In this case, the IP address should be set to the hosts’s IP and only one discovery server will be spawned.

After a moment, the listener should start receiving samples from the talker, meaning that both Discovery Servers are now connected to each other. As the talker and listener nodes share the same topic chatter, nodes are discovered and data exchange can happen. Further benefits of using the new Easy Mode are detailed in the Benefits section.

To stop the Discovery Server spawned in the background and the Fast DDS Daemon, run the following command:

fastdds discovery stop

Otherwise, both will be killed after stopping the container.