Fix for failing to contact master and maybe incorrect documentation on running ROS on multiple machines?

Software
1

Hello,

So I’ve just fixed something and I would like to share that with anyone reading that in the future, and with Husarion because maybe the documentation is incorrect.

Situation

I did the following tutorial:

The roscore is running on my main PC, the connection with the CORE2-ROS is perfectly fine.

When I would run a node/launch file on the Raspberry Pi of the CORE2-ROS I got the following continous stream of error code:

Couldn't find an AF_INET6 address for [192.168.1.128]
[ERROR] [1557302593.719245509]: [registerPublisher] Failed to contact master at [192.168.1.128:11311].  Retrying...
Couldn't find an AF_INET6 address for [192.168.1.128]
Couldn't find an AF_INET6 address for [192.168.1.128]

Solution

Some people had this error but that was because they would not call ros::init() BEFORE the instantiation of your ros::NodeHandle. This was not the problem I was having.

The fix I made after I couldn’t find any solution on the internet was to change last part of the .bashrc file to:

export ROS_MASTER_URI=http://master:11311
# export ROS_IPV6=on

As you can see I commented the export ROS_IPV6=on. This was the fix for me, maybe it was just my case or maybe it’s not documented properly at the tutorial that export ROS_IPV6=on should be commented.

Kind regards,

Mike

2

Hello Mike,

Entries:

export ROS_MASTER_URI=http://master:11311
export ROS_IPV6=on

are for Husarnet configuration. For working in LAN they are not required and should be commented out.

Indeed it was not explained in tutorial, I made a fix for it.

Regards,
Łukasz