Send signal to cri-resmgr process (systemd unit) when forced.cfg changes (updates)

[ppalucki]

May require to add some watcher over files then send signal to cri-resmgr:

Idea here:
kubernetes/kubernetes#24957 (comment)

cri-resmgr supports it as described here:

  -force-config-signal string
        Signal used to reload forced configuration. (default "SIGHUP")

or code here:

but from above it only works for force-config
https://github.com/intel/cri-resource-manager/blob/master/pkg/cri/resource-manager/resource-manager.go#L363
then

// setupConfigSignal sets up a signal handler for reloading forced configuration.
func (m *resmgr) setupConfigSignal(signame string) error {
	if signame == "" || strings.HasPrefix(strings.ToLower(signame), "disable") {
		return nil
	}

	m.Info("setting up signal %s to reload forced configuration", signame)

	sig := unix.SignalNum(signame)
	if int(sig) == 0 {
		return resmgrError("invalid forced configuration reload signal '%s'", signame)
	}

	m.signals = make(chan os.Signal, 1)
	signal.Notify(m.signals, sig)

	go func(signals <-chan os.Signal) {
		for {
			select {
			case _, ok := <-signals:
				if !ok {
					return
				}
			}

			m.Info("reloading forced configuration %s...", opt.ForceConfig)

			if err := m.setConfigFromFile(opt.ForceConfig); err != nil {
				m.Error("failed to reload forced configuration %s: %v",
					opt.ForceConfig, err)
			}
		}
	}(m.signals)

	return nil
}

WARNING if you do not provide --force-config then SIGHUP will kill and restart process