Roscore fails after restart

asked 2020-07-29 10:19:24 -0600

dogulas_T
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I am running ROS Noetic on Ubuntu 20.04.1 LTS

Yesterday I re-installed ROS (it was corrupt) and successfully ran roscore. I left my computer on overnight and this morning it was locked up. I had to do a hard reboot.

Afterwords, when I tried to run roscore, I got the following:

... logging to /home/dtaylor/.ros/log/085907a0-d1ac-11ea-bddb-a1e701cf9cfb/roslaunch-Delta-3256.log
Checking log directory for disk usage. This may take awhile.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.

Resource not found: roslaunch
ROS path [0]=/opt/ros/noetic/share/ros
ROS path [1]=/home/dtaylor/catkin_ws/src
ROS path [2]=/opt/ros/noetic/share
The traceback for the exception was written to the log file

The last time this happened, I had to re-install ROS. Is this the only solution?

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answered 2020-08-01 02:34:30 -0600

gvdhoorn
86574 ●283 ●1432 ●1054 http://cor.tudelft.nl/

It looks like it should be in /opt/ros/noetic/share but it's not. It's also not in /opt/ros/noetic/bin. I did, however, find it in /usr/share and /usr/bin. In /usr/share it is colored blue and in /usr/bin it is colored green. What does that mean?

From what you describe, just as in your previous question (ie: #q356392), you appear to be mixing Noetic packages with wiki/UpstreamPackages.

That will not work, as you've found out.

You'll have to fix this before roscore (and probably other parts of ROS) will start working again.

I added both to my .bachrc file and restarted my terminal but no effect.

This will not affect anything.

Please undo this change.

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gvdhoorn, "you appear to be mixing Noetic packages with wiki/UpstreamPackages". I honestly don't remember doing that. I strictly followed the install instructions at http://wiki.ros.org/ROS/Installation. I didn't even know about the upstream packages. Be that as it may, If I do have a mixed environment, how do I fix it? Can I uninstall everything ROS? Would I have to reformat my hard drive and re-install Ubuntu?

dogulas_T ( 2020-08-13 13:11:21 -0600 )edit

If you have a roslaunch binary/script in /usr/bin, then you must likely have the python3-roslaunch package installed.

That's not the same package as ros-noetic-roslaunch, which would place roslaunch in /opt/ros/noetic/bin.

Does dpkg -l | grep roslaunch return both python3-roslaunch and ros-noetic-roslaunch for you, or just python3-roslaunch? If the latter, that's why you don't have roslaunch.

As to how you ended up in this situation, I don't know.

Can I uninstall everything ROS?

Yes, you'd essentially remove all ros-noetic-* packages, and afterwards probably all packages which are then no longer needed (apt should tell you).

For the upstream packages, you'd have to figure out which packages you have installed. I don't have any specific advice on how to do that.

Would I have to reformat my hard drive and re-install Ubuntu?

That would be the nuclear option, and technically not ...(more)

gvdhoorn ( 2020-08-14 06:08:18 -0600 )edit

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answered 2020-07-29 15:48:45 -0600

praskot
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Did you try source /opt/ros/noetic/setup.bash?

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Thanks praskot, I had the following in my .bachrc file so I wouldn't have to

source /opt/ros/noetic/setup.bash
source ~/catkin_ws/devel/setup.bash

but, just in case that wasn't working I just tried it and got the same results What can I try next?

dogulas_T ( 2020-07-30 14:08:14 -0600 )edit

I'm not really sure, from the error, its not able to find the roslaunch right. Check if you have the roslaunch binary in /opt/ros/noetic/bin. If you do, add it to the path?

praskot ( 2020-07-30 14:37:09 -0600 )edit

It looks like it should be in /opt/ros/noetic/share but it's not. It's also not in /opt/ros/noetic/bin. I did, however, find it in /usr/share and /usr/bin. In /usr/share it is colored blue and in /usr/bin it is colored green. What does that mean?

I added both to my .bachrc file and restarted my terminal but no effect.

dogulas_T ( 2020-07-31 09:49:06 -0600 )edit

More information... I had the following line in my .bashrc file: export ROS_PACKAGE_PATH=/home/dtaylor/catkin_ws/src:/opt/ros/noetic/share:/usr/share:/usr/bin This doesn't seem to work. When I put it directly in at the command prompt it did find one of the roslaunch things. Still don't know which is the executable. questions:

Why does the line not work in my .bashrc file?
Why does roslauch keep disappearing from where it is supposed to be?
What is the color scheme in ls -a?

dogulas_T ( 2020-07-31 09:58:21 -0600 )edit

Try adding export ROS_PACKAGE_PATH=/home/dtaylor/catkin_ws/src:/opt/ros/noetic/share:/usr/share:/usr/bin in the bashrc instead?
Unfortunately, I have no clue why this is happening
As mentioned here https://askubuntu.com/questions/17299/what-do-the-different-colors-mean-in-ls blue implies it is a symbolic link to an executable.

praskot ( 2020-07-31 16:57:44 -0600 )edit

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