Added option to avoid DNS record overwrite

aws/resource_aws_route53_record.go

@@ -232,6 +232,12 @@ func resourceAwsRoute53Record() *schema.Resource {
 				Optional:      true,
 				Set:           schema.HashString,
 			},
+
+			"allow_overwrite": {
+				Type:     schema.TypeBool,
+				Optional: true,
+				Default:  true,
+			},
 		},
 	}
 }
@@ -379,14 +385,24 @@ func resourceAwsRoute53RecordCreate(d *schema.ResourceData, meta interface{}) er
 		return err
 	}
 
+	// Protect existing DNS records which might be managed in another way
+	// Use UPSERT only if the overwrite flag is true or if the current action is an update
+	// Else CREATE is used and fail if the same record exists
+	var action string
+	if d.Get("allow_overwrite").(bool) || !d.IsNewResource() {
+		action = "UPSERT"
+	} else {
+		action = "CREATE"
+	}
+
 	// Create the new records. We abuse StateChangeConf for this to
 	// retry for us since Route53 sometimes returns errors about another
 	// operation happening at the same time.
 	changeBatch := &route53.ChangeBatch{
 		Comment: aws.String("Managed by Terraform"),
 		Changes: []*route53.Change{
 			{
-				Action:            aws.String("UPSERT"),
+				Action:            aws.String(action),
 				ResourceRecordSet: rec,
 			},
 		},

aws/resource_aws_route53_record_test.go

@@ -9,6 +9,8 @@ import (
 	"github.com/hashicorp/terraform/helper/resource"
 	"github.com/hashicorp/terraform/terraform"
 
+	"regexp"
+
 	"github.com/aws/aws-sdk-go/aws"
 	"github.com/aws/aws-sdk-go/aws/awserr"
 	"github.com/aws/aws-sdk-go/service/route53"
@@ -488,6 +490,24 @@ func TestAccAWSRoute53Record_multivalue_answer_basic(t *testing.T) {
 	})
 }
 
+func TestAccAWSRoute53Record_allowOverwrite(t *testing.T) {
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testAccCheckRoute53RecordDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config:      testAccRoute53RecordConfig_allowOverwrite(false),
+				ExpectError: regexp.MustCompile("Tried to create resource record set \\[name='www.notexample.com.', type='A'] but it already exists"),
+			},
+			{
+				Config: testAccRoute53RecordConfig_allowOverwrite(true),
+				Check:  resource.ComposeTestCheckFunc(testAccCheckRoute53RecordExists("aws_route53_record.overwriting")),
+			},
+		},
+	})
+}
+
 func testAccCheckRoute53RecordDestroy(s *terraform.State) error {
 	conn := testAccProvider.Meta().(*AWSClient).r53conn
 	for _, rs := range s.RootModule().Resources {
@@ -573,6 +593,33 @@ func testAccCheckRoute53RecordExists(n string) resource.TestCheckFunc {
 	}
 }
 
+func testAccRoute53RecordConfig_allowOverwrite(allowOverwrite bool) string {
+	return fmt.Sprintf(`
+resource "aws_route53_zone" "main" {
+  name = "notexample.com."
+}
+
+resource "aws_route53_record" "default" {
+  zone_id = "${aws_route53_zone.main.zone_id}"
+  name = "www.notexample.com"
+  type = "A"
+  ttl = "30"
+  records = ["127.0.0.1"]
+}
+
+resource "aws_route53_record" "overwriting" {
+  depends_on = ["aws_route53_record.default"]
+
+  allow_overwrite = %v
+  zone_id = "${aws_route53_zone.main.zone_id}"
+  name = "www.notexample.com"
+  type = "A"
+  ttl = "30"
+  records = ["127.0.0.1"]
+}
+`, allowOverwrite)
+}
+
 const testAccRoute53RecordConfig = `
 resource "aws_route53_zone" "main" {
 	name = "notexample.com"

website/docs/r/route53_record.html.markdown

@@ -108,6 +108,7 @@ The following arguments are supported:
 * `latency_routing_policy` - (Optional) A block indicating a routing policy based on the latency between the requestor and an AWS region. Conflicts with any other routing policy. Documented below.
 * `weighted_routing_policy` - (Optional) A block indicating a weighted routing policy. Conflicts with any other routing policy. Documented below.
 * `multivalue_answer_routing_policy` - (Optional) A block indicating a multivalue answer routing policy. Conflicts with any other routing policy.
+* `allow_overwrite` - (Optional) Allow creation of this record in Terraform to overwrite an existing record, if any. This does not prevent other resources within Terraform or manual Route53 changes from overwriting this record. `true` by default.
 
 Exactly one of `records` or `alias` must be specified: this determines whether it's an alias record.