ROS2 topic list only working once (or any other command)

asked 2020-06-10 03:46:48 -0500

StanSwanborn

21 ●2 ●2 ●3 https://masters.vu.nl/...

Hi,

I am currently using a Turtlebot3, completely set up following this guide: https://emanual.robotis.com/docs/en/p...

Running: ubuntu-18.04.3-preinstalled-server-arm64+raspi3.img.xz With ROS2 Dashing installed.

On my REMOTE PC (desktop), I am running Ubuntu 18.04, also with ROS2 Dashing installed.

Also installed following the online guide: https://index.ros.org/doc/ros2/Instal...

The question:

When I ssh into the Turtlebot3 and run the following command:

ros2 launch turtlebot3_bringup robot.launch.py

and then run on the REMOTE PC (desktop):

ros2 topic list

I get a correct result, showing the available topics that are being published.

However, when I run this command a second time, it only shows the default topics:

/parameter_events

/rosout

Any consecutive command after the first one will give this default result. This is also the case if the first time I try the command:

ros2 node list

or any other ROS2 command. However, when I kill the '_ros2_daemon', and then run the ros2 topic list (or node list) command again, it works again, but only for that one time again. Leaving me to kill the daemon constantly.

Can someone help me figure this out?

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Comments

i have same problme recently..

both on ROS2 version: dashing and foxy

what's wrong?

chopin1998@gmail.com ( 2020-07-31 01:58:32 -0500 )edit

same problem with ros2 foxy, did you find a solution?

emvee ( 2020-12-29 11:37:45 -0500 )edit

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answered 2021-02-21 23:41:57 -0500

saitoros

56 ●3 ●2

I had same problem before. When this problem occur, you should restart ros2 daemon with following commands. $ ros2 daemon stop $ ros2 daemon start After that you can get a correct result on "ros2 topic list command".

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answered 2023-05-03 06:42:45 -0500

R. Tellez
874 ●4 ●18 ●14

Doing the ros2 daemon stop and start do solve momentarily the problem, but the problem appears again after a while (in the same terminal, with the same robots, everything the same). Just a minute or two later.

I think this problem is a common problem. It looks to me that nobody knows a real solution to it, and, more important, why is it happenning, and how to debug what is happenning.

I don't know how to solve it nor why/when it happens, just found particular tricks for each time I'm with this problem, which do not apply to other situations.

Anybody can provide a clarification about this issue?

To clarify: the configuration is, several computers in a wifi network, each one launching ROS 2 nodes that need to communicate with each other. DDS implementation: whatever that works.