Handle cleanup DNS for attachable container

Attachable containers they are tasks with no service associated
their cleanup was not done properly so it was possible to have
a leak of their name resolution if that was the last container
on the network.
Cleanupservicebindings was not able to do the cleanup because there
is no service, while also the notification of the delete arrives
after that the network is already being cleaned

Signed-off-by: Flavio Crisciani <flavio.crisciani@docker.com>

controller.go

@@ -341,6 +341,7 @@ func (c *controller) clusterAgentInit() {
 			// should still be present when cleaning up
 			// service bindings
 			c.agentClose()
+			c.cleanupServiceDiscovery("")
 			c.cleanupServiceBindings("")
 
 			c.agentStopComplete()

network.go

@@ -995,6 +995,10 @@ func (n *network) delete(force bool) error {
 		logrus.Errorf("Failed leaving network %s from the agent cluster: %v", n.Name(), err)
 	}
 
+	// Cleanup the service discovery for this network
+	c.cleanupServiceDiscovery(n.ID())
+
+	// Cleanup the load balancer
 	c.cleanupServiceBindings(n.ID())
 
 removeFromStore:

networkdb/networkdb.go

@@ -499,7 +499,10 @@ func (nDB *NetworkDB) deleteNodeNetworkEntries(nid, node string) {
 					// without doing a delete of all the objects
 					entry.ltime++
 				}
-				nDB.createOrUpdateEntry(nid, tname, key, entry)
+
+				if !oldEntry.deleting {
+					nDB.createOrUpdateEntry(nid, tname, key, entry)
+				}
 			} else {
 				// the local node is leaving the network, all the entries of remote nodes can be safely removed
 				nDB.deleteEntry(nid, tname, key)

service_common.go

@@ -161,6 +161,19 @@ func (c *controller) getLBIndex(sid, nid string, ingressPorts []*PortConfig) int
 	return int(lb.fwMark)
 }
 
+// cleanupServiceDiscovery when the network is being deleted, erase all the associated service discovery records
+func (c *controller) cleanupServiceDiscovery(cleanupNID string) {
+	c.Lock()
+	defer c.Unlock()
+	if cleanupNID == "" {
+		logrus.Debugf("cleanupServiceDiscovery for all networks")
+		c.svcRecords = make(map[string]svcInfo)
+		return
+	}
+	logrus.Debugf("cleanupServiceDiscovery for network:%s", cleanupNID)
+	delete(c.svcRecords, cleanupNID)
+}
+
 func (c *controller) cleanupServiceBindings(cleanupNID string) {
 	var cleanupFuncs []func()
 
@@ -184,15 +197,6 @@ func (c *controller) cleanupServiceBindings(cleanupNID string) {
 				continue
 			}
 
-			// The network is being deleted, erase all the associated service discovery records
-			// TODO(fcrisciani) separate the Load Balancer from the Service discovery, this operation
-			// can be done safely here, but the rmServiceBinding is still keeping consistency in the
-			// data structures that are tracking the endpoint to IP mapping.
-			c.Lock()
-			logrus.Debugf("cleanupServiceBindings erasing the svcRecords for %s", nid)
-			delete(c.svcRecords, nid)
-			c.Unlock()
-
 			for eid, ip := range lb.backEnds {
 				epID := eid
 				epIP := ip