ros2 turtlesim

edit

Hi guys,

I am using ros2 dashing and work with turtlesim (1.0.1). Unfortunatly, I realized that a number of features described in the tutorial do not work for me.

1. Action Servers explained in Understanding ROS Actions are not available. According to the tutorial I expected to see something like Action Servers: /turtle1/rotate_absolute: turtlesim/action/RotateAbsolute. But when I run

   ros2 node info /turtlesim

no actions are visible.

    /turtlesim
    Subscribers:
        ...
    Publishers:
        ...
     Services:
        ...

1. The Parameter setting is described in Understanding ROS2 Parameters. When I run

   ros2 param set /turtlesim background_r 150

I receive

    Set parameter successful

but nothing happens, the background remains in the same color as before. I assume that I am doing something wrong. Does someone have advice for me?

Best wishes!

Sebastian