Sets placement constraints on the TaskDefinition resource.

Placement constraints on a service are not updateable, which means making changes via CloudFormation would require a replacement of the ECS service. Instead, we set the placement constraints on the task definition, and update the existing service with the new task definition.
remind101 · Aug 9, 2017 · 537490d · 537490d
1 parent 3b5357d
commit 537490d
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Showing 5 changed files with 52 additions and 18 deletions.
diff --git a/scheduler/cloudformation/resources.go b/scheduler/cloudformation/resources.go
@@ -5,6 +5,11 @@ type PortMappingProperties struct {
 	HostPort      interface{} `json:",omitempty"`
 }
 
+type PlacementConstraint struct {
+	Type       interface{} `json:",omitempty"`
+	Expression interface{} `json:",omitempty"`
+}
+
 type ContainerDefinitionProperties struct {
 	Command          interface{}              `json:",omitempty"`
 	Cpu              interface{}              `json:",omitempty"`
@@ -20,12 +25,14 @@ type ContainerDefinitionProperties struct {
 }
 
 type TaskDefinitionProperties struct {
+	PlacementConstraints []*PlacementConstraint           `json:",omitempty"`
 	ContainerDefinitions []*ContainerDefinitionProperties `json:",omitempty"`
 	Volumes              []interface{}
 	TaskRoleArn          interface{} `json:",omitempty"`
 }
 
 type CustomTaskDefinitionProperties struct {
+	PlacementConstraints []*PlacementConstraint           `json:",omitempty"`
 	ContainerDefinitions []*ContainerDefinitionProperties `json:",omitempty"`
 	Family               interface{}                      `json:",omitempty"`
 	ServiceToken         interface{}                      `json:",omitempty"`

diff --git a/scheduler/cloudformation/template.go b/scheduler/cloudformation/template.go
@@ -289,6 +289,18 @@ func (t *EmpireTemplate) addTaskDefinition(tmpl *troposphere.Template, app *twel
 	// running tasks.
 	taskRole := toInterface(taskRoleArn(app))
 
+	var placementConstraints []*PlacementConstraint
+	if v := p.ECS; v != nil {
+		if len(v.PlacementConstraints) > 0 {
+			for _, c := range v.PlacementConstraints {
+				placementConstraints = append(placementConstraints, &PlacementConstraint{
+					Type:       c.Type,
+					Expression: c.Expression,
+				})
+			}
+		}
+	}
+
 	var taskDefinitionProperties interface{}
 	taskDefinitionType := taskDefinitionResourceType(app)
 	if taskDefinitionType == "Custom::ECSTaskDefinition" {
@@ -314,7 +326,8 @@ func (t *EmpireTemplate) addTaskDefinition(tmpl *troposphere.Template, app *twel
 			ContainerDefinitions: []*ContainerDefinitionProperties{
 				containerDefinition,
 			},
-			TaskRoleArn: taskRole,
+			TaskRoleArn:          taskRole,
+			PlacementConstraints: placementConstraints,
 		}
 	} else {
 		containerDefinition.Environment = cd.Environment
@@ -323,7 +336,8 @@ func (t *EmpireTemplate) addTaskDefinition(tmpl *troposphere.Template, app *twel
 			ContainerDefinitions: []*ContainerDefinitionProperties{
 				containerDefinition,
 			},
-			TaskRoleArn: taskRole,
+			TaskRoleArn:          taskRole,
+			PlacementConstraints: placementConstraints,
 		}
 	}
 
@@ -691,16 +705,6 @@ func (t *EmpireTemplate) addService(tmpl *troposphere.Template, app *twelvefacto
 		"ServiceToken":   t.CustomResourcesTopic,
 	}
 	if v := p.ECS; v != nil {
-		if len(v.PlacementConstraints) > 0 {
-			var placementConstraints []interface{}
-			for _, c := range v.PlacementConstraints {
-				placementConstraints = append(placementConstraints, map[string]interface{}{
-					"Type":       c.Type,
-					"Expression": c.Expression,
-				})
-			}
-			serviceProperties["PlacementConstraints"] = placementConstraints
-		}
 		if len(v.PlacementStrategy) > 0 {
 			var placementStrategy []interface{}
 			for _, c := range v.PlacementStrategy {

diff --git a/scheduler/cloudformation/templates/ecs-extra.json b/scheduler/cloudformation/templates/ecs-extra.json
@@ -205,12 +205,6 @@
             }
           }
         ],
-        "PlacementConstraints": [
-          {
-            "Expression": "attribute:ecs.instance-type =~ t2.*",
-            "Type": "memberOf"
-          }
-        ],
         "Role": "ecsServiceRole",
         "ServiceName": "acme-inc-web",
         "ServiceToken": "sns topic arn",
@@ -222,6 +216,12 @@
     },
     "webTaskDefinition": {
       "Properties": {
+        "PlacementConstraints": [
+          {
+            "Type": "memberOf",
+            "Expression": "attribute:ecs.instance-type =~ t2.*"
+          }
+        ],
         "ContainerDefinitions": [
           {
             "Command": [

diff --git a/server/cloudformation/ecs.go b/server/cloudformation/ecs.go
@@ -263,6 +263,7 @@ type ECSTaskDefinitionProperties struct {
 	Family               *string
 	TaskRoleArn          *string
 	ContainerDefinitions []ContainerDefinition
+	PlacementConstraints []ECSPlacementConstraint
 }
 
 func (p *ECSTaskDefinitionProperties) ReplacementHash() (uint64, error) {
@@ -360,10 +361,20 @@ func (p *ECSTaskDefinitionResource) register(properties *ECSTaskDefinitionProper
 	if properties.Family != nil {
 		family = aws.String(fmt.Sprintf("%s-%s", *properties.Family, postfix))
 	}
+
+	var placementConstraints []*ecs.TaskDefinitionPlacementConstraint
+	for _, v := range properties.PlacementConstraints {
+		placementConstraints = append(placementConstraints, &ecs.TaskDefinitionPlacementConstraint{
+			Type:       v.Type,
+			Expression: v.Expression,
+		})
+	}
+
 	resp, err := p.ecs.RegisterTaskDefinition(&ecs.RegisterTaskDefinitionInput{
 		Family:               family,
 		TaskRoleArn:          properties.TaskRoleArn,
 		ContainerDefinitions: containerDefinitions,
+		PlacementConstraints: placementConstraints,
 	})
 	if err != nil {
 		return "", fmt.Errorf("error creating task definition: %v", err)

diff --git a/server/cloudformation/ecs_test.go b/server/cloudformation/ecs_test.go
@@ -404,6 +404,12 @@ func TestECSTaskDefinition_Create(t *testing.T) {
 				},
 			},
 		},
+		PlacementConstraints: []*ecs.TaskDefinitionPlacementConstraint{
+			{
+				Type:       aws.String("memberOf"),
+				Expression: aws.String("attribute:instance-type =~ t1.micro"),
+			},
+		},
 	}).Return(&ecs.RegisterTaskDefinitionOutput{
 		TaskDefinition: &ecs.TaskDefinition{
 			TaskDefinitionArn: aws.String("arn:aws:ecs:us-east-1:012345678901:task-definition/acme-inc-web"),
@@ -422,6 +428,12 @@ func TestECSTaskDefinition_Create(t *testing.T) {
 					},
 				},
 			},
+			PlacementConstraints: []ECSPlacementConstraint{
+				{
+					Type:       aws.String("memberOf"),
+					Expression: aws.String("attribute:instance-type =~ t1.micro"),
+				},
+			},
 		},
 	})
 	assert.NoError(t, err)