Merge pull request #2436 from dongluochen/rescheduleWithOverlay

Reschedule containers with global network

Author: dongluochen

cluster/watchdog.go

@@ -2,8 +2,11 @@ package cluster
 
 import (
 	"sync"
+	"time"
 
 	log "github.com/Sirupsen/logrus"
+	"github.com/docker/engine-api/types/network"
+	"golang.org/x/net/context"
 )
 
 // Watchdog listens to cluster events and handles container rescheduling
@@ -61,6 +64,7 @@ func (w *Watchdog) rescheduleContainers(e *Engine) {
 	defer w.Unlock()
 
 	log.Debugf("Node %s failed - rescheduling containers", e.ID)
+
 	for _, c := range e.Containers() {
 
 		// Skip containers which don't have an "on-node-failure" reschedule policy.
@@ -75,23 +79,76 @@ func (w *Watchdog) rescheduleContainers(e *Engine) {
 		// will abort because the name is already taken.
 		c.Engine.removeContainer(c)
 
-		newContainer, err := w.cluster.CreateContainer(c.Config, c.Info.Name, nil)
+		// keep track of all global networks this container is connected to
+		globalNetworks := make(map[string]*network.EndpointSettings)
+		// if the existing containter has global network endpoints,
+		// they need to be removed with force option
+		// "docker network disconnect -f network containername" only takes containername
+		name := c.Info.Name
+		if len(name) == 0 || len(name) == 1 && name[0] == '/' {
+			log.Errorf("container %s has no name", c.ID)
+			continue
+		}
+		// cut preceeding '/'
+		if name[0] == '/' {
+			name = name[1:]
+		}
+
+		if c.NetworkSettings != nil && len(c.NetworkSettings.Networks) > 0 {
+			// find an engine to do disconnect work
+			randomEngine, err := w.cluster.RANDOMENGINE()
+			if err != nil {
+				log.Errorf("Failed to find an engine to do network cleanup for container %s: %v", c.ID, err)
+				// add the container back, so we can retry later
+				c.Engine.AddContainer(c)
+				continue
+			}
+
+			clusterNetworks := w.cluster.Networks().Uniq()
+			for networkName, endpoint := range c.NetworkSettings.Networks {
+				net := clusterNetworks.Get(endpoint.NetworkID)
+				if net != nil && net.Scope == "global" {
+					// record the nework, they should be reconstructed on the new container
+					globalNetworks[networkName] = endpoint
+					ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+					defer cancel()
+					err = randomEngine.apiClient.NetworkDisconnect(ctx, networkName, name, true)
+					if err != nil {
+						// do not abort here as this endpoint might have been removed before
+						log.Warnf("Failed to remove network endpoint from old container %s: %v", name, err)
+					}
+				}
+			}
+		}
 
+		newContainer, err := w.cluster.CreateContainer(c.Config, c.Info.Name, nil)
 		if err != nil {
 			log.Errorf("Failed to reschedule container %s: %v", c.ID, err)
 			// add the container back, so we can retry later
 			c.Engine.AddContainer(c)
-		} else {
-			log.Infof("Rescheduled container %s from %s to %s as %s", c.ID, c.Engine.Name, newContainer.Engine.Name, newContainer.ID)
-			if c.Info.State.Running {
-				log.Infof("Container %s was running, starting container %s", c.ID, newContainer.ID)
-				if err := w.cluster.StartContainer(newContainer, nil); err != nil {
-					log.Errorf("Failed to start rescheduled container %s: %v", newContainer.ID, err)
-				}
+			continue
+		}
+
+		// Docker create command cannot create a container with multiple networks
+		// see https://github.com/docker/docker/issues/17750
+		// Add the global networks one by one
+		for networkName, endpoint := range globalNetworks {
+			ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+			defer cancel()
+			err = newContainer.Engine.apiClient.NetworkConnect(ctx, networkName, name, endpoint)
+			if err != nil {
+				log.Warnf("Failed to connect network %s to container %s: %v", networkName, name, err)
 			}
 		}
-	}
 
+		log.Infof("Rescheduled container %s from %s to %s as %s", c.ID, c.Engine.Name, newContainer.Engine.Name, newContainer.ID)
+		if c.Info.State.Running {
+			log.Infof("Container %s was running, starting container %s", c.ID, newContainer.ID)
+			if err := w.cluster.StartContainer(newContainer, nil); err != nil {
+				log.Errorf("Failed to start rescheduled container %s: %v", newContainer.ID, err)
+			}
+		}
+	}
 }
 
 // NewWatchdog creates a new watchdog