providers/aws: Validate IOPs for EBS Volumes

builtin/providers/aws/resource_aws_ebs_volume.go

@@ -76,9 +76,6 @@ func resourceAwsEbsVolumeCreate(d *schema.ResourceData, meta interface{}) error
 	if value, ok := d.GetOk("encrypted"); ok {
 		request.Encrypted = aws.Bool(value.(bool))
 	}
-	if value, ok := d.GetOk("iops"); ok {
-		request.Iops = aws.Int64(int64(value.(int)))
-	}
 	if value, ok := d.GetOk("kms_key_id"); ok {
 		request.KmsKeyId = aws.String(value.(string))
 	}
@@ -88,18 +85,35 @@ func resourceAwsEbsVolumeCreate(d *schema.ResourceData, meta interface{}) error
 	if value, ok := d.GetOk("snapshot_id"); ok {
 		request.SnapshotId = aws.String(value.(string))
 	}
+
+	// IOPs are only valid, and required for, storage type io1. The current minimu
+	// is 100. Instead of a hard validation we we only apply the IOPs to the
+	// request if the type is io1, and log a warning otherwise. This allows users
+	// to "disable" iops. See https://github.com/hashicorp/terraform/pull/4146
+	var t string
 	if value, ok := d.GetOk("type"); ok {
-		request.VolumeType = aws.String(value.(string))
+		t = value.(string)
+		request.VolumeType = aws.String(t)
+	}
+
+	iops := d.Get("iops").(int)
+	if t != "io1" && iops > 0 {
+		log.Printf("[WARN] IOPs is only valid for storate type io1 for EBS Volumes")
+	} else if t == "io1" {
+		// We add the iops value without validating it's size, to allow AWS to
+		// enforce a size requirement (currently 100)
+		request.Iops = aws.Int64(int64(iops))
 	}
 
+	log.Printf(
+		"[DEBUG] EBS Volume create opts: %s", request)
 	result, err := conn.CreateVolume(request)
 	if err != nil {
 		return fmt.Errorf("Error creating EC2 volume: %s", err)
 	}
 
-	log.Printf(
-		"[DEBUG] Waiting for Volume (%s) to become available",
-		d.Id())
+	log.Println(
+		"[DEBUG] Waiting for Volume to become available")
 
 	stateConf := &resource.StateChangeConf{
 		Pending:    []string{"creating"},
@@ -199,9 +213,6 @@ func readVolume(d *schema.ResourceData, volume *ec2.Volume) error {
 	if volume.Encrypted != nil {
 		d.Set("encrypted", *volume.Encrypted)
 	}
-	if volume.Iops != nil {
-		d.Set("iops", *volume.Iops)
-	}
 	if volume.KmsKeyId != nil {
 		d.Set("kms_key_id", *volume.KmsKeyId)
 	}
@@ -214,6 +225,17 @@ func readVolume(d *schema.ResourceData, volume *ec2.Volume) error {
 	if volume.VolumeType != nil {
 		d.Set("type", *volume.VolumeType)
 	}
+
+	if volume.VolumeType != nil && *volume.VolumeType == "io1" {
+		// Only set the iops attribute if the volume type is io1. Setting otherwise
+		// can trigger a refresh/plan loop based on the computed value that is given
+		// from AWS, and prevent us from specifying 0 as a valid iops.
+		//   See https://github.com/hashicorp/terraform/pull/4146
+		if volume.Iops != nil {
+			d.Set("iops", *volume.Iops)
+		}
+	}
+
 	if volume.Tags != nil {
 		d.Set("tags", tagsToMap(volume.Tags))
 	}

builtin/providers/aws/resource_aws_ebs_volume_test.go

@@ -26,6 +26,22 @@ func TestAccAWSEBSVolume_basic(t *testing.T) {
 	})
 }
 
+func TestAccAWSEBSVolume_NoIops(t *testing.T) {
+	var v ec2.Volume
+	resource.Test(t, resource.TestCase{
+		PreCheck:  func() { testAccPreCheck(t) },
+		Providers: testAccProviders,
+		Steps: []resource.TestStep{
+			resource.TestStep{
+				Config: testAccAwsEbsVolumeConfigWithNoIops,
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckVolumeExists("aws_ebs_volume.iops_test", &v),
+				),
+			},
+		},
+	})
+}
+
 func TestAccAWSEBSVolume_withTags(t *testing.T) {
 	var v ec2.Volume
 	resource.Test(t, resource.TestCase{
@@ -86,3 +102,15 @@ resource "aws_ebs_volume" "tags_test" {
 	}
 }
 `
+
+const testAccAwsEbsVolumeConfigWithNoIops = `
+resource "aws_ebs_volume" "iops_test" {
+	availability_zone = "us-west-2a"
+	size = 10
+  type = "gp2"
+	iops = 0
+	tags {
+		Name = "TerraformTest"
+	}
+}
+`

website/source/docs/providers/aws/r/ebs_volume.html.md

@@ -14,7 +14,7 @@ Manages a single EBS volume.
 
 ```
 resource "aws_ebs_volume" "example" {
-    availability_zone = "us-west-1a"
+    availability_zone = "us-west-2a"
     size = 40
     tags {
         Name = "HelloWorld"