Merge pull request #971 from jimmyxian/reschedule-with-image

Reschedule with soft image affinity

cluster/config.go

@@ -146,3 +146,15 @@ func (c *ContainerConfig) Affinities() []string {
 func (c *ContainerConfig) Constraints() []string {
 	return c.extractExprs("constraints")
 }
+
+// AddAffinity to config
+func (c *ContainerConfig) AddAffinity(affinity string) error {
+	affinities := c.extractExprs("affinities")
+	affinities = append(affinities, affinity)
+	labels, err := json.Marshal(affinities)
+	if err != nil {
+		return err
+	}
+	c.Labels[SwarmLabelNamespace+".affinities"] = string(labels)
+	return nil
+}

cluster/config_test.go

@@ -81,3 +81,11 @@ func TestConsolidateResourceFields(t *testing.T) {
 	}
 
 }
+
+func TestAddAffinity(t *testing.T) {
+	config := BuildContainerConfig(dockerclient.ContainerConfig{})
+	assert.Empty(t, config.Affinities())
+
+	config.AddAffinity("image==~testimage")
+	assert.Len(t, config.Affinities(), 1)
+}

cluster/swarm/cluster.go

@@ -89,6 +89,20 @@ func (c *Cluster) generateUniqueID() string {
 
 // CreateContainer aka schedule a brand new container into the cluster.
 func (c *Cluster) CreateContainer(config *cluster.ContainerConfig, name string) (*cluster.Container, error) {
+	container, err := c.createContainer(config, name, false)
+
+	//  fails with image not found, then try to reschedule with soft-image-affinity
+	if err != nil && strings.HasSuffix(err.Error(), "not found") {
+		// Check if the image exists in the cluster
+		// If exists, retry with a soft-image-affinity
+		if image := c.Image(config.Image); image != nil {
+			container, err = c.createContainer(config, name, true)
+		}
+	}
+	return container, err
+}
+
+func (c *Cluster) createContainer(config *cluster.ContainerConfig, name string, withSoftImageAffinity bool) (*cluster.Container, error) {
 	c.scheduler.Lock()
 	defer c.scheduler.Unlock()
 
@@ -100,7 +114,12 @@ func (c *Cluster) CreateContainer(config *cluster.ContainerConfig, name string)
 	// Associate a Swarm ID to the container we are creating.
 	config.SetSwarmID(c.generateUniqueID())
 
-	n, err := c.scheduler.SelectNodeForContainer(c.listNodes(), config)
+	configTemp := config
+	if withSoftImageAffinity {
+		configTemp.AddAffinity("image==~" + config.Image)
+	}
+
+	n, err := c.scheduler.SelectNodeForContainer(c.listNodes(), configTemp)
 	if err != nil {
 		return nil, err
 	}

test/integration/api/run.bats

@@ -66,3 +66,25 @@ function teardown() {
 	# pid
 	[[ "${output}" == *"\"PidMode\": \"host\""* ]]
 }
+
+@test "docker run - reschedule with soft-image-affinity" {
+	start_docker_with_busybox 1
+	start_docker 1
+
+	docker -H ${HOSTS[0]} tag busybox:latest busyboxabcde:latest
+	swarm_manage
+
+	# make sure busyboxabcde exists
+	run docker_swarm images
+	[ "$status" -eq 0 ]
+	[[ "${output}" == *"busyboxabcde"* ]]
+
+	# try to create container on node-1, node-1 does not have busyboxabcde and will pull it
+	# but can not find busyboxabcde in dockerhub
+	# then will retry with soft-image-affinity
+	docker_swarm run -d --name test_container -e constraint:node==~node-1 busyboxabcde sleep 1000
+
+	# check container running on node-0
+	run docker_swarm ps
+	[[ "${output}" == *"node-0/test_container"* ]]
+}