Launch nodes on different machines that share one roscore

Hi,

first of all thanks a lot for sharing and maintaining this awesome tool!

I have a question about how to use node_manager with the current setup we have (and I’m not sure if this is possible).

We have 4 PCs (see pictures):

• A runs its own roscore and node_manager. It’s connected over WiFi to the other PCs.
• B runs its own roscore and it’s connected to the router.
• C has ROS_MASTER_URI=http://B:11311 set in its .bashrc and is connected to the router.
• D has ROS_MASTER_URI=http://B:11311 set in its .bashrc and is connected to the router.

Given this setup (that cannot be easily changed) I’m able to sync A and B using node_manager, but I don’t know how to include C and D, while keeping their ROS_MASTER_URI “pointing” to B. The goal is to launch specific launch files on B, C, and D from A. Is this possible with node_manager, without having to run roscores on C and D?

Thanks for your help. Marco.

[atiderko]

@marco-tranzatto thank you very much for your feedback!

[marco-tranzatto]

Hi @atiderko

I found time to test your suggestions and so far it works as expected. Thanks a lot for being so fast to implement this extra feature!

For further reference, in case anybody else is interested in the same setup, these are some important points to keep in mind:

• Use latest version of node manager, with the feature introduced as explained at the beginning of this thread.
• When using the machine tag, remember to:
  • Use RSA algorithm to copy the ssh key from one pc to another (applies for A to all the others, and from B to C and D). For example: ssh-copy-id -oHostKeyAlgorithms='ssh-rsa' user@host
  • Use “env-loader script” (see example). On PCs C and D I put the following lines in the script:
    • source ~/catkin_ws/devel/setup.bash
    • export ROS_MASTER_URI=http://host-pc-a:11311
    • exec "$@"
• Have one launch file to be launched on pc B that launches nodes on B, and uses one machine tag for C and one for D, to “distribute” nodes across machines.

Regards, Marco.