resource/aws_opsworks_stack: Use Default VPC when no VPC ID passed

.changelog/26711.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+resource/aws_opsworks_stack: Defaults to default VPC when not supplied
+```

internal/acctest/acctest.go

@@ -709,7 +709,7 @@ func PreCheckRegionNot(t *testing.T, regions ...string) {
 // PreCheckAlternateRegionIs checks that the alternate test region is the specified region.
 func PreCheckAlternateRegionIs(t *testing.T, region string) {
 	if curr := AlternateRegion(); curr != region {
-		t.Skipf("skipping tests; %s (%s) does not equal %s", conns.EnvVarDefaultRegion, curr, region)
+		t.Skipf("skipping tests; %s (%s) does not equal %s", conns.EnvVarAlternateRegion, curr, region)
 	}
 }
 

internal/service/acm/sweep.go

@@ -72,7 +72,7 @@ func sweepCertificates(region string) error {
 				for _, iub := range output.Certificate.InUseBy {
 					m[aws.StringValue(iub)[:77]] = ""
 				}
-				for k, _ := range m {
+				for k := range m {
 					log.Printf("[INFO]  %s...", k)
 				}
 				continue

internal/service/ec2/vpc_security_group_test.go

@@ -2498,7 +2498,6 @@ resource "aws_security_group" "test" {
 data "aws_vpc" "default" {
   default = true
 }
-
 `, rName)
 }
 
@@ -2512,7 +2511,6 @@ resource "aws_security_group" "test" {
 data "aws_vpc" "default" {
   default = true
 }
-
 `, rName)
 }
 

internal/service/opsworks/stack.go

@@ -1,7 +1,6 @@
 package opsworks
 
 import (
-	"errors"
 	"fmt"
 	"log"
 	"time"
@@ -112,10 +111,10 @@ func ResourceStack() *schema.Resource {
 				DiffSuppressFunc: verify.SuppressEquivalentJSONDiffs,
 			},
 			"default_availability_zone": {
-				Type:         schema.TypeString,
-				Optional:     true,
-				Computed:     true,
-				ExactlyOneOf: []string{"default_availability_zone", "vpc_id"},
+				Type:          schema.TypeString,
+				Optional:      true,
+				Computed:      true,
+				ConflictsWith: []string{"vpc_id"},
 			},
 			"default_instance_profile_arn": {
 				Type:     schema.TypeString,
@@ -182,11 +181,11 @@ func ResourceStack() *schema.Resource {
 				Default:  true,
 			},
 			"vpc_id": {
-				Type:         schema.TypeString,
-				ForceNew:     true,
-				Computed:     true,
-				Optional:     true,
-				ExactlyOneOf: []string{"default_availability_zone", "vpc_id"},
+				Type:          schema.TypeString,
+				ForceNew:      true,
+				Computed:      true,
+				Optional:      true,
+				ConflictsWith: []string{"default_availability_zone"},
 			},
 		},
 
@@ -199,10 +198,6 @@ func resourceStackCreate(d *schema.ResourceData, meta interface{}) error {
 	defaultTagsConfig := meta.(*conns.AWSClient).DefaultTagsConfig
 	tags := defaultTagsConfig.MergeTags(tftags.New(d.Get("tags").(map[string]interface{})))
 
-	if _, ok := d.GetOk("vpc_id"); !ok {
-		return errors.New(`with the retirement of EC2-Classic no new OpsWorks Stacks can be created without referencing a VPC`)
-	}
-
 	name := d.Get("name").(string)
 	region := d.Get("region").(string)
 	input := &opsworks.CreateStackInput{

internal/service/opsworks/stack_test.go

@@ -98,6 +98,80 @@ func TestAccOpsWorksStack_disappears(t *testing.T) {
 	})
 }
 
+func TestAccOpsWorksStack_noVPC_basic(t *testing.T) {
+	rName := sdkacctest.RandomWithPrefix(acctest.ResourcePrefix)
+	resourceName := "aws_opsworks_stack.test"
+	var v opsworks.Stack
+
+	resource.ParallelTest(t, resource.TestCase{
+		PreCheck: func() {
+			acctest.PreCheck(t)
+			acctest.PreCheckPartitionHasService(opsworks.EndpointsID, t)
+			testAccPreCheckStacks(t)
+		},
+		ErrorCheck:               acctest.ErrorCheck(t, opsworks.EndpointsID),
+		ProtoV5ProviderFactories: acctest.ProtoV5ProviderFactories,
+		CheckDestroy:             testAccCheckStackDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccStackConfig_noVPC(rName),
+				Check: resource.ComposeAggregateTestCheckFunc(
+					testAccCheckStackExists(resourceName, &v),
+					resource.TestMatchResourceAttr(resourceName, "default_availability_zone", regexp.MustCompile(fmt.Sprintf("%s[a-z]", acctest.Region()))),
+					resource.TestMatchResourceAttr(resourceName, "default_subnet_id", regexp.MustCompile("subnet-[[:alnum:]]")),
+					resource.TestCheckResourceAttrPair(resourceName, "vpc_id", "data.aws_vpc.default", "id"),
+				),
+			},
+			{
+				ResourceName:      resourceName,
+				ImportState:       true,
+				ImportStateVerify: true,
+			},
+			{
+				Config:   testAccStackConfig_defaultVPC(rName),
+				PlanOnly: true,
+			},
+			{
+				Config:   testAccStackConfig_noVPC(rName),
+				PlanOnly: true,
+			},
+		},
+	})
+}
+
+func TestAccOpsWorksStack_noVPC_defaultAZ(t *testing.T) {
+	rName := sdkacctest.RandomWithPrefix(acctest.ResourcePrefix)
+	resourceName := "aws_opsworks_stack.test"
+	var v opsworks.Stack
+
+	resource.ParallelTest(t, resource.TestCase{
+		PreCheck: func() {
+			acctest.PreCheck(t)
+			acctest.PreCheckPartitionHasService(opsworks.EndpointsID, t)
+			testAccPreCheckStacks(t)
+		},
+		ErrorCheck:               acctest.ErrorCheck(t, opsworks.EndpointsID),
+		ProtoV5ProviderFactories: acctest.ProtoV5ProviderFactories,
+		CheckDestroy:             testAccCheckStackDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccStackConfig_noVPCDefaultAZ(rName),
+				Check: resource.ComposeAggregateTestCheckFunc(
+					testAccCheckStackExists(resourceName, &v),
+					resource.TestCheckResourceAttrPair(resourceName, "default_availability_zone", "data.aws_availability_zones.available", "names.1"),
+					resource.TestMatchResourceAttr(resourceName, "default_subnet_id", regexp.MustCompile("subnet-[[:alnum:]]")),
+					resource.TestCheckResourceAttrPair(resourceName, "vpc_id", "data.aws_vpc.default", "id"),
+				),
+			},
+			{
+				ResourceName:      resourceName,
+				ImportState:       true,
+				ImportStateVerify: true,
+			},
+		},
+	})
+}
+
 func TestAccOpsWorksStack_tags(t *testing.T) {
 	rName := sdkacctest.RandomWithPrefix(acctest.ResourcePrefix)
 	resourceName := "aws_opsworks_stack.test"
@@ -461,7 +535,7 @@ func testAccCheckStackDestroy(s *terraform.State) error {
 	return nil
 }
 
-func testAccStackConfig_base(rName string) string {
+func testAccStackConfig_baseIAM(rName string) string {
 	return fmt.Sprintf(`
 resource "aws_iam_role" "opsworks_service" {
   name = "%[1]s-service"
@@ -527,13 +601,16 @@ resource "aws_iam_instance_profile" "opsworks_instance" {
 }
 
 func testAccStackConfig_baseVPC(rName string) string {
-	return acctest.ConfigCompose(testAccStackConfig_base(rName), acctest.ConfigVPCWithSubnets(rName, 2))
+	return acctest.ConfigCompose(
+		testAccStackConfig_baseIAM(rName),
+		acctest.ConfigVPCWithSubnets(rName, 2),
+	)
 }
 
 func testAccStackConfig_baseVPCAlternateRegion(rName string) string {
 	return acctest.ConfigCompose(
 		acctest.ConfigMultipleRegionProvider(2),
-		testAccStackConfig_base(rName),
+		testAccStackConfig_baseIAM(rName),
 		fmt.Sprintf(`
 # The VPC (and subnets) must be in the target (alternate) AWS Region.
 data "aws_availability_zones" "available" {
@@ -587,6 +664,63 @@ resource "aws_opsworks_stack" "test" {
 `, rName, acctest.Region()))
 }
 
+func testAccStackConfig_noVPC(rName string) string {
+	return acctest.ConfigCompose(
+		testAccStackConfig_baseIAM(rName),
+		fmt.Sprintf(`
+resource "aws_opsworks_stack" "test" {
+  name                         = %[1]q
+  region                       = %[2]q
+  service_role_arn             = aws_iam_role.opsworks_service.arn
+  default_instance_profile_arn = aws_iam_instance_profile.opsworks_instance.arn
+  use_opsworks_security_groups = false
+}
+
+data "aws_vpc" "default" {
+  default = true
+}
+`, rName, acctest.Region()))
+}
+
+func testAccStackConfig_defaultVPC(rName string) string {
+	return acctest.ConfigCompose(
+		testAccStackConfig_baseIAM(rName),
+		fmt.Sprintf(`
+resource "aws_opsworks_stack" "test" {
+  name                         = %[1]q
+  region                       = %[2]q
+  service_role_arn             = aws_iam_role.opsworks_service.arn
+  default_instance_profile_arn = aws_iam_instance_profile.opsworks_instance.arn
+  use_opsworks_security_groups = false
+  vpc_id                       = data.aws_vpc.default.id
+}
+
+data "aws_vpc" "default" {
+  default = true
+}
+`, rName, acctest.Region()))
+}
+
+func testAccStackConfig_noVPCDefaultAZ(rName string) string {
+	return acctest.ConfigCompose(
+		testAccStackConfig_baseIAM(rName),
+		acctest.ConfigAvailableAZsNoOptInDefaultExclude(),
+		fmt.Sprintf(`
+resource "aws_opsworks_stack" "test" {
+  name                         = %[1]q
+  region                       = %[2]q
+  service_role_arn             = aws_iam_role.opsworks_service.arn
+  default_instance_profile_arn = aws_iam_instance_profile.opsworks_instance.arn
+  use_opsworks_security_groups = false
+  default_availability_zone    = data.aws_availability_zones.available.names[1]
+}
+
+data "aws_vpc" "default" {
+  default = true
+}
+`, rName, acctest.Region()))
+}
+
 func testAccStackConfig_tags1(rName, tagKey1, tagValue1 string) string {
 	return acctest.ConfigCompose(testAccStackConfig_baseVPC(rName), fmt.Sprintf(`
 resource "aws_opsworks_stack" "test" {

website/docs/r/opsworks_stack.html.markdown

@@ -40,32 +40,29 @@ The following arguments are supported:
 * `name` - (Required) The name of the stack.
 * `region` - (Required) The name of the region where the stack will exist.
 * `service_role_arn` - (Required) The ARN of an IAM role that the OpsWorks service will act as.
-* `default_instance_profile_arn` - (Required) The ARN of an IAM Instance Profile that created instances
-  will have by default.
+* `default_instance_profile_arn` - (Required) The ARN of an IAM Instance Profile that created instances will have by default.
 * `agent_version` - (Optional) If set to `"LATEST"`, OpsWorks will automatically install the latest version.
 * `berkshelf_version` - (Optional) If `manage_berkshelf` is enabled, the version of Berkshelf to use.
 * `color` - (Optional) Color to paint next to the stack's resources in the OpsWorks console.
-* `default_availability_zone` - (Optional) Name of the availability zone where instances will be created
-  by default. This is required unless you set `vpc_id`.
 * `configuration_manager_name` - (Optional) Name of the configuration manager to use. Defaults to "Chef".
 * `configuration_manager_version` - (Optional) Version of the configuration manager to use. Defaults to "11.4".
-* `custom_cookbooks_source` - (Optional) When `use_custom_cookbooks` is set, provide this sub-object as
-  described below.
+* `custom_cookbooks_source` - (Optional) When `use_custom_cookbooks` is set, provide this sub-object as described below.
 * `custom_json` - (Optional) User defined JSON passed to "Chef". Use a "here doc" for multiline JSON.
+* `default_availability_zone` - (Optional) Name of the availability zone where instances will be created by default.
+  Cannot be set when `vpc_id` is set.
 * `default_os` - (Optional) Name of OS that will be installed on instances by default.
 * `default_root_device_type` - (Optional) Name of the type of root device instances will have by default.
 * `default_ssh_key_name` - (Optional) Name of the SSH keypair that instances will have by default.
-* `default_subnet_id` - (Optional) Id of the subnet in which instances will be created by default. Mandatory
-  if `vpc_id` is set, and forbidden if it isn't.
-* `hostname_theme` - (Optional) Keyword representing the naming scheme that will be used for instance hostnames
-  within this stack.
+* `default_subnet_id` - (Optional) ID of the subnet in which instances will be created by default.
+  Required if `vpc_id` is set to a VPC other than the default VPC, and forbidden if it isn't.
+* `hostname_theme` - (Optional) Keyword representing the naming scheme that will be used for instance hostnames within this stack.
 * `manage_berkshelf` - (Optional) Boolean value controlling whether Opsworks will run Berkshelf for this stack.
-* `tags` - (Optional) A map of tags to assign to the resource. If configured with a provider [`default_tags` configuration block](https://registry.terraform.io/providers/hashicorp/aws/latest/docs#default_tags-configuration-block) present, tags with matching keys will overwrite those defined at the provider-level.
-* `use_custom_cookbooks` - (Optional) Boolean value controlling whether the custom cookbook settings are
-  enabled.
-* `use_opsworks_security_groups` - (Optional) Boolean value controlling whether the standard OpsWorks
-  security groups apply to created instances.
+* `tags` - (Optional) A map of tags to assign to the resource.
+  If configured with a provider [`default_tags` configuration block](https://registry.terraform.io/providers/hashicorp/aws/latest/docs#default_tags-configuration-block) present, tags with matching keys will overwrite those defined at the provider-level.
+* `use_custom_cookbooks` - (Optional) Boolean value controlling whether the custom cookbook settings are enabled.
+* `use_opsworks_security_groups` - (Optional) Boolean value controlling whether the standard OpsWorks security groups apply to created instances.
 * `vpc_id` - (Optional) ID of the VPC that this stack belongs to.
+  Defaults to the region's default VPC.
 * `custom_json` - (Optional) Custom JSON attributes to apply to the entire stack.
 
 The `custom_cookbooks_source` block supports the following arguments: