Unable to communicate with ros master when running roscore

asked 2021-07-29 03:16:49 -0500

SuleKayiran gravatar image

Hello to everyone! I have a problem. I am using ros kinetic. I set up two computers as master slaves. It was working correctly before. Communication with ros master was possible. Can't communicate now. Here is my configuration in bashrc;

Master Computer:

export ROS_IP=192.168.101.1
export ROS_MASTER_URI=http://192.168.101.1:11311

slave computer:

export ROS_IP= 192.168.101.2
export ROS_MASTER_URI=http://192.168.101.1:11311

and I can run roscore on master pc, but when running launch file on my slave computers, I get Unable to communicate with master warning. I would be glad if you help.

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Comments

Just curious: could you add a few words on why you are using Kinetic? Do you have some dependency or driver or other constraint which made you use that ROS version specifically?

gvdhoorn gravatar image gvdhoorn  ( 2021-07-29 03:21:42 -0500 )edit

Oh, and just to clear up: there is no master-slave distribution of roles here. ROS is peer-to-peer. There is a ROS Master, but that does not mean the other PCs are slaves. It's master in the sense of "the single source of truth".

gvdhoorn gravatar image gvdhoorn  ( 2021-07-29 03:22:47 -0500 )edit

Hi, I'm very new to Ros and thought it might be helpful to specify the version of Ros. Because I don't know if it has anything to do with this issue and if it's something that might change in other ros versions. @gvdhoorn

SuleKayiran gravatar image SuleKayiran  ( 2021-07-29 03:57:44 -0500 )edit

Mentioning the version of ROS you're using is fine.

I'm more curious as to why you're still using ROS Kinetic. It has been end-of-life (meaning: no longer supported) for about 5 months now, so does not get any updates nor fixes.

gvdhoorn gravatar image gvdhoorn  ( 2021-07-29 04:26:56 -0500 )edit

Yes, I understand better now. In the online trainings I have received, teachers give training through ros kinetic. and now the packages I want to do are complete and good for kinetics, there are many resources on github. I found some packages unstable or not available in the neotic version so I continue on kinetics until I improve myself and my project doesn't lag. @gvdhoorn

SuleKayiran gravatar image SuleKayiran  ( 2021-07-29 05:40:23 -0500 )edit

That space character after "ROS_IP=" on 2nd computer is probably not good. Tell us what you have done to make sure the network is working between the two.

Mike Scheutzow gravatar image Mike Scheutzow  ( 2021-07-30 14:05:49 -0500 )edit

Hello, first of all, sorry for my late reply. I'm verifying communication between the two computers by pinging it. The interesting thing is that when I switch computers, I mean master pc to slave pc, when I switch slave pc to master, everything works fine. And I am applying the same network configuration as I mentioned above.

SuleKayiran gravatar image SuleKayiran  ( 2021-08-13 01:31:37 -0500 )edit