Furthermore, after ssh into the python containers, i run the commands and met with error.

root@73c23b7eda2b:/python-service# FLASK_APP=main.py python -m flask run --port 3000 --host 0.0.0.0
Usage: python -m flask [OPTIONS] COMMAND [ARGS]…
Try “python -m flask — help” for help.

Error: No such command “run --port”.