Connection refused to the Ubuntu VM when using roswtf
The following is the result of the command roswtf, after having launched roslaunch turtle_tf turtle_tf_demo.launch (and nothing else).
nbro@nbro-virtual-machine:~$ roswtf
Loaded plugin tf.tfwtf
No package or stack in context
================================================================================
Static checks summary:
No errors or warnings
================================================================================
Beginning tests of your ROS graph. These may take awhile...
analyzing graph...
... done analyzing graph
running graph rules...
ERROR: connection refused to [http://nbro-virtual-machine:34235/]
... done running graph rules
running tf checks, this will take a second...
... tf checks complete
Online checks summary:
Found 1 warning(s).
Warnings are things that may be just fine, but are sometimes at fault
WARNING The following node subscriptions are unconnected:
* /turtle_pointer:
* /tf_static
Found 3 error(s).
ERROR Could not contact the following nodes:
* /turtlesim
ERROR The following nodes should be connected but aren't:
* /teleop->/turtlesim (/turtle1/cmd_vel)
* /turtlesim->/turtle1_tf_broadcaster (/turtle1/pose)
ERROR Errors connecting to the following services:
* service [/turtlesim/get_loggers] appears to be malfunctioning: Unable to communicate with service [/turtlesim/get_loggers], address [rosrpc://nbro-virtual-machine:55709]
* service [/turtlesim/set_logger_level] appears to be malfunctioning: Unable to communicate with service [/turtlesim/set_logger_level], address [rosrpc://nbro-virtual-machine:55709]
I am trying to understand why I am getting these errors. I first have a "connection refused" to http://nbro-virtual-machine:34235/, but I am executing this command from the same machine the nodes (e.g. /turtlesim) are running.
The second error says
ERROR Could not contact the following nodes:
* /turtlesim
However, rosnode list tells me the /turtlesim is running.
I have seen other posts with similar errors. I decided to close all the terminals, including the one which launched roscore. I executed roswtf again, after roslaunch turtle_tf turtle_tf_demo.launch, and now I don't have the errors above anymore, but just a warning:
WARNING The following node subscriptions are unconnected:
* /turtle_pointer:
* /tf_static
What's happening? Why did roswtf think that certain nodes (e.g. /teleop) were supposed to be connected (to what? to the master?), even though some of them were not connected but some were?
I doubt the fact that you're running in a VM has anything to do with this, and "the Ubuntu VM" is also a bit of a misnomer. It's a regular VM, it just happens to be running Ubuntu.