I have created a launch file. In this file, there are two groups. Each group has two nodes: turlesim_node and turtle_teleop_key node. Then, I executed this launch file by using roslaunch command.

Launch File:

<launch>

  <group ns="turtlesim1">
    <node pkg="turtlesim" name="sim" type="turtlesim_node"/>
    <node pkg="turtlesim" name="teleop_key" type="turtle_teleop_key"/>
  </group>

  <group ns="turtlesim2">
    <node pkg="turtlesim" name="sim" type="turtlesim_node"/>
    <node pkg="turtlesim" name="teleop_key" type="turtle_teleop_key"/>
  </group>
</launch>

My expectation: Two simulator screens and two tele-operation keyboard screens open and I manage these simulator turtles by using tele-operation keyboard screens. If I use first teleop keyboard screen, first turtlesim moves. If I use second teleop keyboard screen, second turtlesim moves.

What happened: Two simlator screens opened and one tele-op screen opened. When I stroke keyboard buttons in tele-op screen, sometimes first turtlesim moves, and sometimes second turtlesim moves.

How can it be possible ?

I have two tele operation keyboard nodes right now. I checked it by using the command rosnode list.