[Bug] Could not enable FIFO RT scheduling policy

[slimasziom]

Current Situation:
During launch controller manager cannot enable real-time scheduling:

[ros2_control_node-6] [INFO] [1751442500.999166362] [controller_manager]: update rate is 100 Hz [ros2_control_node-6] [INFO] [1751442500.999203502] [controller_manager]: Spawning controller_manager RT thread with scheduler priority: 50 [ros2_control_node-6] [WARN] [1751442501.002182839] [controller_manager]: Could not enable FIFO RT scheduling policy: with error number <1>(Operation not permitted). See [https://control.ros.org/master/doc/ros2_control/controller_manager/doc/userdoc.html] for details on how to enable realtime scheduling.

Expected:
All real-time setup launches properly.

Workaround:
None

[macmacal]

• To overcome this problem, the project must be lunched on a host with PREEMPT-RT kernel.
• When I was developing initial Docker container, I was following this tutorial: https://github.com/2b-t/linux-realtime/tree/main

To run Docker with RT capabilities, add this to the docker-compose file:

    cap_add:
      - SYS_NICE
    ulimits:
      rtprio: 99
      rttime: -1 # corresponds to 'unlimited'
      memlock: 8428281856
    network_mode: host

[macmacal]

TODO: check if this problem still occurs