Merge pull request #36590 from hashicorp/b-ec2-instance-change-type

ec2/instance: Replace instance when architecture changes

.changelog/36590.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+resource/aws_instance: Replace an instance when an `instance_type` change also requires an architecture change, such as x86_64 to arm64
+```

internal/service/ec2/ec2_instance.go

@@ -901,6 +901,40 @@ func ResourceInstance() *schema.Resource {
 			customdiff.ForceNewIf("user_data_base64", func(_ context.Context, diff *schema.ResourceDiff, meta interface{}) bool {
 				return diff.Get("user_data_replace_on_change").(bool)
 			}),
+			customdiff.ForceNewIf("instance_type", func(ctx context.Context, diff *schema.ResourceDiff, meta interface{}) bool {
+				conn := meta.(*conns.AWSClient).EC2Conn(ctx)
+
+				_, ok := diff.GetOk("instance_type")
+
+				if diff.Id() == "" || !diff.HasChange("instance_type") || !ok {
+					return false
+				}
+
+				o, n := diff.GetChange("instance_type")
+				it1, err := FindInstanceTypeByName(ctx, conn, o.(string))
+				if err != nil {
+					return false
+				}
+
+				it2, err := FindInstanceTypeByName(ctx, conn, n.(string))
+				if err != nil {
+					return false
+				}
+
+				if it1 == nil || it2 == nil {
+					return false
+				}
+
+				if aws.StringValue(it1.InstanceType) == aws.StringValue(it2.InstanceType) {
+					return false
+				}
+
+				if hasCommonElement(it1.ProcessorInfo.SupportedArchitectures, it2.ProcessorInfo.SupportedArchitectures) {
+					return false
+				}
+
+				return true
+			}),
 		),
 	}
 }
@@ -3984,3 +4018,14 @@ func ParseInstanceType(s string) (*InstanceType, error) {
 		Size:                   matches[5],
 	}, nil
 }
+
+func hasCommonElement(slice1 []*string, slice2 []*string) bool {
+	for _, str1 := range slice1 {
+		for _, str2 := range slice2 {
+			if aws.StringValue(str1) == aws.StringValue(str2) {
+				return true
+			}
+		}
+	}
+	return false
+}

internal/service/ec2/ec2_instance_test.go

@@ -2259,7 +2259,7 @@ func TestAccEC2Instance_changeInstanceType(t *testing.T) {
 		CheckDestroy:             testAccCheckInstanceDestroy(ctx),
 		Steps: []resource.TestStep{
 			{
-				Config: testAccInstanceConfig_smallType(rName),
+				Config: testAccInstanceConfig_type(rName, "t2.medium"),
 				Check: resource.ComposeTestCheckFunc(
 					testAccCheckInstanceExists(ctx, resourceName, &before),
 					resource.TestCheckResourceAttr(resourceName, "instance_type", "t2.medium"),
@@ -2272,7 +2272,7 @@ func TestAccEC2Instance_changeInstanceType(t *testing.T) {
 				ImportStateVerifyIgnore: []string{"user_data_replace_on_change"},
 			},
 			{
-				Config: testAccInstanceConfig_updateType(rName),
+				Config: testAccInstanceConfig_type(rName, "t2.large"),
 				Check: resource.ComposeTestCheckFunc(
 					testAccCheckInstanceExists(ctx, resourceName, &after),
 					testAccCheckInstanceNotRecreated(&before, &after),
@@ -2283,6 +2283,38 @@ func TestAccEC2Instance_changeInstanceType(t *testing.T) {
 	})
 }
 
+func TestAccEC2Instance_changeInstanceTypeReplace(t *testing.T) {
+	ctx := acctest.Context(t)
+	var before ec2.Instance
+	var after ec2.Instance
+	resourceName := "aws_instance.test"
+	rName := sdkacctest.RandomWithPrefix(acctest.ResourcePrefix)
+
+	resource.ParallelTest(t, resource.TestCase{
+		PreCheck:                 func() { acctest.PreCheck(ctx, t) },
+		ErrorCheck:               acctest.ErrorCheck(t, names.EC2ServiceID),
+		ProtoV5ProviderFactories: acctest.ProtoV5ProviderFactories,
+		CheckDestroy:             testAccCheckInstanceDestroy(ctx),
+		Steps: []resource.TestStep{
+			{
+				Config: testAccInstanceConfig_typeReplace(rName, "m5.2xlarge"),
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckInstanceExists(ctx, resourceName, &before),
+					resource.TestCheckResourceAttr(resourceName, "instance_type", "m5.2xlarge"),
+				),
+			},
+			{
+				Config: testAccInstanceConfig_typeReplace(rName, "m6g.2xlarge"),
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckInstanceExists(ctx, resourceName, &after),
+					testAccCheckInstanceRecreated(&before, &after),
+					resource.TestCheckResourceAttr(resourceName, "instance_type", "m6g.2xlarge"),
+				),
+			},
+		},
+	})
+}
+
 func TestAccEC2Instance_changeInstanceTypeAndUserData(t *testing.T) {
 	ctx := acctest.Context(t)
 	var v ec2.Instance
@@ -6195,7 +6227,7 @@ resource "aws_instance" "test" {
 `, rName, filename))
 }
 
-func testAccInstanceConfig_smallType(rName string) string {
+func testAccInstanceConfig_type(rName, instanceType string) string {
 	return acctest.ConfigCompose(
 		acctest.ConfigLatestAmazonLinux2HVMEBSX8664AMI(),
 		testAccInstanceVPCConfig(rName, false, 0),
@@ -6204,31 +6236,41 @@ resource "aws_instance" "test" {
   ami       = data.aws_ami.amzn2-ami-minimal-hvm-ebs-x86_64.id
   subnet_id = aws_subnet.test.id
 
-  instance_type = "t2.medium"
+  instance_type = %[1]q
 
   tags = {
-    Name = %[1]q
+    Name = %[2]q
   }
 }
-`, rName))
+`, instanceType, rName))
 }
 
-func testAccInstanceConfig_updateType(rName string) string {
+func testAccInstanceConfig_typeReplace(rName, instanceType string) string {
+	arch := acctest.ConfigLatestAmazonLinux2HVMEBSX8664AMI()
+	archs := "x86_64"
+	if strings.HasPrefix(instanceType, "m6g.") {
+		arch = acctest.ConfigLatestAmazonLinux2HVMEBSARM64AMI()
+		archs = "arm64"
+	}
 	return acctest.ConfigCompose(
-		acctest.ConfigLatestAmazonLinux2HVMEBSX8664AMI(),
+		arch,
 		testAccInstanceVPCConfig(rName, false, 0),
 		fmt.Sprintf(`
 resource "aws_instance" "test" {
-  ami       = data.aws_ami.amzn2-ami-minimal-hvm-ebs-x86_64.id
+  ami       = data.aws_ami.amzn2-ami-minimal-hvm-ebs-%[3]s.id
   subnet_id = aws_subnet.test.id
 
-  instance_type = "t2.large"
+  instance_type = %[1]q
 
   tags = {
-    Name = %[1]q
+    Name = %[2]q
+  }
+
+  lifecycle {
+    ignore_changes = [ami]
   }
 }
-`, rName))
+`, instanceType, rName, archs))
 }
 
 func testAccInstanceConfig_typeAndUserData(rName, instanceType, userData string) string {