[FIX] Don't ignore silently service proxy errors. (cloudnativelabs#796)

Currently we can have error on service proxy if we cannot set sysctl (in my case), but those errors are return and not shown. Just show them, like other controllers

Author: nerzhul

pkg/controllers/proxy/network_services_controller.go

@@ -276,7 +276,7 @@ type endpointsInfo struct {
 type endpointsInfoMap map[string][]endpointsInfo
 
 // Run periodically sync ipvs configuration to reflect desired state of services and endpoints
-func (nsc *NetworkServicesController) Run(healthChan chan<- *healthcheck.ControllerHeartbeat, stopCh <-chan struct{}, wg *sync.WaitGroup) error {
+func (nsc *NetworkServicesController) Run(healthChan chan<- *healthcheck.ControllerHeartbeat, stopCh <-chan struct{}, wg *sync.WaitGroup) {
 	t := time.NewTicker(nsc.syncPeriod)
 	defer t.Stop()
 	defer wg.Done()
@@ -287,25 +287,25 @@ func (nsc *NetworkServicesController) Run(healthChan chan<- *healthcheck.Control
 	err := ensureMasqueradeIptablesRule(nsc.masqueradeAll, nsc.podCidr)
 	// enable masquerade rule
 	if err != nil {
-		return errors.New("Failed to do add masquerade rule in POSTROUTING chain of nat table due to: %s" + err.Error())
+		glog.Errorf("Failed to do add masquerade rule in POSTROUTING chain of nat table due to: %s", err.Error())
 	}
 	// https://www.kernel.org/doc/Documentation/networking/ipvs-sysctl.txt
 	// enable ipvs connection tracking
 	sysctlErr := utils.SetSysctl("net/ipv4/vs/conntrack", 1)
 	if sysctlErr != nil {
-		return errors.New(sysctlErr.Error())
+		glog.Error(sysctlErr.Error())
 	}
 
 	// LVS failover not working with UDP packets https://access.redhat.com/solutions/58653
 	sysctlErr = utils.SetSysctl("net/ipv4/vs/expire_nodest_conn", 1)
 	if sysctlErr != nil {
-		return errors.New(sysctlErr.Error())
+		glog.Error(sysctlErr.Error())
 	}
 
 	// LVS failover not working with UDP packets https://access.redhat.com/solutions/58653
 	sysctlErr = utils.SetSysctl("net/ipv4/vs/expire_quiescent_template", 1)
 	if sysctlErr != nil {
-		return errors.New(sysctlErr.Error())
+		glog.Error(sysctlErr.Error())
 	}
 
 	// https://github.com/kubernetes/kubernetes/pull/71114
@@ -314,27 +314,28 @@ func (nsc *NetworkServicesController) Run(healthChan chan<- *healthcheck.Control
 		// Check if the error is fatal, on older kernels this option does not exist and the same behaviour is default
 		// if option is not found just log it
 		if sysctlErr.IsFatal() {
-			return errors.New(sysctlErr.Error())
+			glog.Fatal(sysctlErr.Error())
+		} else {
+			glog.Info(sysctlErr.Error())
 		}
-		glog.Info(sysctlErr.Error())
 	}
 
 	// https://github.com/kubernetes/kubernetes/pull/70530/files
 	sysctlErr = utils.SetSysctl("net/ipv4/conf/all/arp_ignore", 1)
 	if sysctlErr != nil {
-		return errors.New(sysctlErr.Error())
+		glog.Error(sysctlErr.Error())
 	}
 
 	// https://github.com/kubernetes/kubernetes/pull/70530/files
 	sysctlErr = utils.SetSysctl("net/ipv4/conf/all/arp_announce", 2)
 	if sysctlErr != nil {
-		return errors.New(sysctlErr.Error())
+		glog.Error(sysctlErr.Error())
 	}
 
 	// https://github.com/cloudnativelabs/kube-router/issues/282
 	err = nsc.setupIpvsFirewall()
 	if err != nil {
-		return errors.New("Error setting up ipvs firewall: " + err.Error())
+		glog.Error("Error setting up ipvs firewall: " + err.Error())
 	}
 
 	gracefulTicker := time.NewTicker(5 * time.Second)
@@ -343,7 +344,7 @@ func (nsc *NetworkServicesController) Run(healthChan chan<- *healthcheck.Control
 	select {
 	case <-stopCh:
 		glog.Info("Shutting down network services controller")
-		return nil
+		return
 	default:
 		err := nsc.doSync()
 		if err != nil {
@@ -357,7 +358,7 @@ func (nsc *NetworkServicesController) Run(healthChan chan<- *healthcheck.Control
 		select {
 		case <-stopCh:
 			glog.Info("Shutting down network services controller")
-			return nil
+			return
 
 		case <-gracefulTicker.C:
 			if nsc.readyForUpdates && nsc.gracefulTermination {