00
In productionProadvancedQoS durability
The late subscriber never learns its config
Let a config client that joins after the one-shot /robot_config publish still receive the latched sample, without changing the publisher.
Pairs with Parameters and launch in ROS 2 Systems Debugging. Read the concept first, then diagnose it here.
Unlock this lab with ProOperator report
/robot_config appears in `ros2 topic list`, but the client's /config_status stays 'PENDING' forever because it started after the single latched publish.
Ubuntu 24.04, ROS 2 Jazzy, Python and C++ nodes, browser telemetry workspace
System boundary
Trace only the relevant path.
- 01config_broadcaster→
- 02/robot_config→
- 03config_clientOUT
02
How this lab works
You diagnose it. No command list.
Open the repair workspace and gather your own evidence in a real terminal. No diagnostic commands are handed to you - finding the fault is the exercise. Stuck? Progressive hints unlock inside the workspace.
Verification
Pass more than the visible symptom.
- Client publishes /config_status
- Late-joining client receives the latched /robot_config
- Hidden regression behavior
- Root cause explanation