ROS 2 Lyrical Luth · Lesson 26 of 86

Installing Gazebo Harmonic

Gazebo Sim, ros_gz packages, checking the version pairing and running the first world.

Estimated time · 45–60 min

Learning goals

What you will understand

Explain installing gazebo harmonic in your own words
Use it in a small robotics example
Verify the result instead of assuming it worked

Understand the idea first

The mental model

Gazebo is the physics simulator used with ROS 2. Modern Gazebo (formerly Ignition) is installed as gz-sim and connects to ROS 2 through the ros_gz packages. Each ROS 2 distribution supports specific Gazebo versions: check the ros_gz table for the pairing before installing (this course uses Gazebo Harmonic).

After installing, start it with gz sim and a world file. gz topic and gz service are the simulator's own tools, similar to the ros2 CLI. Software rendering can be slow; a GPU or a reduced scene helps.

Guided lesson

Work through these steps

1.
Source the ROS 2 Lyrical environment in a fresh terminal.
2.
Read the installing gazebo harmonic example and identify what each line does.
3.
Build only the affected package, source the workspace overlay, and run the example.
4.
Inspect the result from a second terminal with the ros2 CLI or RViz2 and compare it with the expected result.

Worked example

Read it before you run it

sudo apt update
# Refresh the package index.
sudo apt install ros-lyrical-ros-gz
# Install Gazebo and the ROS 2 bridge packages for this distribution.
gz sim --version
# Confirm the Gazebo version.
gz sim -v 3 shapes.sdf
# Open the built-in shapes world with verbose logging.
gz topic -l
# List Gazebo's own topics.
ros2 pkg list | grep ros_gz
# Confirm the ROS 2 bridge packages are visible.

What the example is doing

1.The ros2 commands query the running graph; they do not prove that a node's internal behavior is correct.
2.Build from the workspace root, then source install/setup.bash so the shell can discover the new package.
3.Use a second sourced terminal to inspect nodes and interfaces while the example runs.

Watch it run · Mobile robot

See what this code does

The terminal types this lesson's practice solution and runs it. The scene shows the kind of robot behaviour that code drives. It plays by itself and loops.

Practice code

Now type it yourself

Copy the starter into your ROS 2 package, replace every TODO, then build with colcon build and run it from a sourced terminal.

source /opt/ros/lyrical/setup.bash
# TODO: open the built-in world shapes.sdf with gz sim and verbosity 3

Expected output

The Gazebo window opens with shapes

Stuck? Show the full solution (try it yourself first)

source /opt/ros/lyrical/setup.bash
gz sim -v 3 shapes.sdf

Expected result

How you know it worked

ROS_DISTRO is lyrical in every terminal used for the exercise.
The complete package from the exercise builds and the expected graph entity appears in a second terminal.

Practical exercise

Apply the lesson

Install ros_gz, start shapes.sdf, press Play, list gz topics, and record the Gazebo version and the pairing table entry for your ROS 2 distribution.

Before you continue

ROS_DISTRO reports lyrical in every terminal you used
The example builds and runs without errors
You checked the result with a ros2 command, RViz2 or a test, not just by reading the code

If something goes wrong

ros2 cannot find a package or executable.

Source /opt/ros/lyrical/setup.bash, build from the workspace root, then source install/setup.bash in that terminal.

Nodes run but cannot discover each other.

Confirm both terminals use Lyrical, the same ROS_DOMAIN_ID, and compatible network/discovery settings.