https://github.com/inotify-tools/inotify-tools/wiki

[error] `inotify-tools` is needed to run `file_system` for your system, check https://github.com/rvoicilas/inotify-tools/wiki for more information about how to install it. If it's already installed but not be found, appoint executable file with `config.exs` or `FILESYSTEM_FSINOTIFY_EXECUTABLE_FILE` env

解决：

apt-get install inotify-tools