Rosbag doesn't record cmd_vel on remote master
I'm running Electric on Natty and have the following peculiar issue.
When I run rosbag -a on the above host, the bag output records cmd_vel. However, when I collect rosbag output after setting ROS_MASTER_URI to a different host (which runs diamondback on Lucid), I don't get cmd_vel recorded. Even
shell> rosbag record cmd_vel -a
fails to record cmd_vel in such a case, although all other topics are logged. Note that cmd_vel is being published always. What could be the problem?
Updated after Lorenzo's answer rostopic echo /cmd_vel gives the right output in such a case.
Probably not the cause, but mixing Electric and Diamondback in a single ROS graph is a bad idea and not supported.