Introduce dns-enable option to deploy DNS provider

Author: dvavili

netmaster/main.go

@@ -39,6 +39,7 @@ type cliOpts struct {
 	storeURL    string
 	listenURL   string
 	clusterMode string
+	dnsEnabled  bool
 	version     bool
 }
 
@@ -107,6 +108,10 @@ func parseOpts(opts *cliOpts) error {
 		"cluster-mode",
 		"docker",
 		"{docker, kubernetes}")
+	flagSet.BoolVar(&opts.dnsEnabled,
+		"dns-enable",
+		true,
+		"Turn on DNS {true, false}")
 	flagSet.BoolVar(&opts.version,
 		"version",
 		false,
@@ -142,6 +147,10 @@ func execOpts(opts *cliOpts) core.StateDriver {
 		log.Fatalf("Failed to set cluster-mode. Error: %s", err)
 	}
 
+	if err := master.SetDNSEnabled(opts.dnsEnabled); err != nil {
+		log.Fatalf("Failed to set dns-enable. Error: %s", err)
+	}
+
 	sd, err := initStateDriver(opts)
 	if err != nil {
 		log.Fatalf("Failed to init state-store. Error: %s", err)

netmaster/master/netmaster.go

@@ -38,6 +38,7 @@ const (
 // Run Time config of netmaster
 type nmRunTimeConf struct {
 	clusterMode string
+	dnsEnabled  bool
 }
 
 var masterRTCfg nmRunTimeConf
@@ -53,6 +54,7 @@ func SetClusterMode(cm string) error {
 	}
 
 	masterRTCfg.clusterMode = cm
+	SetDNSEnabled(false)
 	return nil
 }
 
@@ -61,6 +63,22 @@ func GetClusterMode() string {
 	return masterRTCfg.clusterMode
 }
 
+// IsDNSEnabled gets the status of whether DNS is enabled
+func IsDNSEnabled() bool {
+	return masterRTCfg.dnsEnabled
+}
+
+// SetDNSEnabled sets the status of DNS Enable
+func SetDNSEnabled(dnsEnableFlag bool) error {
+	log.Infof("Setting dns flag to %s", dnsEnableFlag)
+	masterRTCfg.dnsEnabled = dnsEnableFlag
+	return nil
+}
+
+func getDNSName(tenantName string) string {
+	return tenantName + "dns"
+}
+
 func getEpName(networkName string, ep *intent.ConfigEP) string {
 	if ep.Container != "" {
 		return networkName + "-" + ep.Container
@@ -196,12 +214,12 @@ func CreateTenant(stateDriver core.StateDriver, tenant *intent.ConfigTenant) err
 		return err
 	}
 
-	if GetClusterMode() == "docker" {
+	if IsDNSEnabled() {
 		// start skydns container
 		err = startServiceContainer(tenant.Name)
 		if err != nil {
-			log.Errorf("Error starting service container. Err: %v", err)
-			return err
+			log.Errorf("Error starting service container. Err: %v. Disabling DNS option.", err)
+			SetDNSEnabled(false)
 		}
 	}
 
@@ -243,7 +261,7 @@ func startServiceContainer(tenantName string) error {
 			"SKYDNS_ADDR=0.0.0.0:53",
 			"SKYDNS_DOMAIN=" + tenantName}}
 
-	containerID, err := docker.CreateContainer(containerConfig, tenantName+"dns", nil)
+	containerID, err := docker.CreateContainer(containerConfig, getDNSName(tenantName), nil)
 	if err != nil {
 		log.Errorf("Error creating DNS container for tenant: %s. Error: %s", tenantName, err)
 	}
@@ -268,7 +286,7 @@ func stopAndRemoveServiceContainer(tenantName string) error {
 		return err
 	}
 
-	dnsContName := tenantName + "dns"
+	dnsContName := getDNSName(tenantName)
 	// Stop the container
 	err = docker.StopContainer(dnsContName, 10)
 	if err != nil {
@@ -286,15 +304,17 @@ func stopAndRemoveServiceContainer(tenantName string) error {
 
 // DeleteTenantID deletes a tenant from the state store, by ID.
 func DeleteTenantID(stateDriver core.StateDriver, tenantID string) error {
-	if GetClusterMode() == "docker" {
-		err := stopAndRemoveServiceContainer(tenantID)
+	var err error
+
+	if IsDNSEnabled() {
+		err = stopAndRemoveServiceContainer(tenantID)
 		if err != nil {
 			log.Errorf("Error in stopping service container for tenant: %+v", tenantID)
 			return err
 		}
 	}
 
-	return nil
+	return err
 }
 
 // DeleteTenant deletes a tenant from the state store based on its ConfigTenant.

netmaster/master/network.go

@@ -148,7 +148,9 @@ func CreateNetwork(network intent.ConfigNetwork, stateDriver core.StateDriver, t
 			log.Errorf("Error creating network %s in docker. Err: %v", nwCfg.ID, err)
 			return err
 		}
+	}
 
+	if IsDNSEnabled() {
 		// Attach service container endpoint to the network
 		err = attachServiceContainer(tenantName, network.Name, stateDriver)
 		if err != nil {
@@ -162,7 +164,7 @@ func CreateNetwork(network intent.ConfigNetwork, stateDriver core.StateDriver, t
 }
 
 func attachServiceContainer(tenantName, networkName string, stateDriver core.StateDriver) error {
-	contName := tenantName + "dns"
+	contName := getDNSName(tenantName)
 	docker, err := utils.GetDockerClient()
 	if err != nil {
 		log.Errorf("Unable to connect to docker. Error %v", err)
@@ -236,7 +238,7 @@ func detachServiceContainer(tenantName, networkName string) error {
 		return errors.New("Unable to connect to docker")
 	}
 
-	dnsContName := tenantName + "dns"
+	dnsContName := getDNSName(tenantName)
 	cinfo, err := docker.InspectContainer(dnsContName)
 	if err != nil {
 		log.Errorf("Error inspecting the container %s. Err: %v", dnsContName, err)
@@ -338,18 +340,20 @@ func DeleteNetworkID(stateDriver core.StateDriver, netID string) error {
 		return err
 	}
 
-	// Check if there are any active endpoints
-	if hasActiveEndpoints(nwCfg) {
-		return core.Errorf("Error: Network has active endpoints")
-	}
-
-	if GetClusterMode() == "docker" {
+	if IsDNSEnabled() {
 		// detach Dns container
 		err = detachServiceContainer(nwCfg.Tenant, nwCfg.NetworkName)
 		if err != nil {
 			log.Errorf("Error detaching service container. Err: %v", err)
 		}
+	}
 
+	// Check if there are any active endpoints
+	if hasActiveEndpoints(nwCfg) {
+		return core.Errorf("Error: Network has active endpoints")
+	}
+
+	if GetClusterMode() == "docker" {
 		// Delete the docker network
 		err = docknet.DeleteDockNet(nwCfg.Tenant, nwCfg.NetworkName, "")
 		if err != nil {
@@ -499,9 +503,5 @@ func networkReleaseAddress(nwCfg *mastercfg.CfgNetworkState, ipAddress string) e
 }
 
 func hasActiveEndpoints(nwCfg *mastercfg.CfgNetworkState) bool {
-	// Uncomment the below after https://github.com/contiv/netplugin/pull/269 is merged
-	// We spin a dns container if IsDNSEnabled() == true
-	// We need to exlude that from Active EPs check.
-	//return (IsDNSEnabled() && nwCfg.EpCount > 1) || ((!IsDNSEnabled()) && nwCfg.EpCount > 0)
-	return nwCfg.EpCount > 1
+	return nwCfg.EpCount > 0
 }