Add hostname field to compute_instance (#2952)

Signed-off-by: Modular Magician <magic-modules@google.com>

google/resource_compute_instance.go

@@ -537,6 +537,12 @@ func resourceComputeInstance() *schema.Resource {
 				Type:     schema.TypeString,
 				Computed: true,
 			},
+
+			"hostname": {
+				Type:     schema.TypeString,
+				Optional: true,
+				ForceNew: true,
+			},
 		},
 		CustomizeDiff: customdiff.All(
 			customdiff.If(
@@ -674,6 +680,7 @@ func expandComputeInstance(project string, zone *compute.Zone, d *schema.Resourc
 		MinCpuPlatform:     d.Get("min_cpu_platform").(string),
 		Scheduling:         scheduling,
 		DeletionProtection: d.Get("deletion_protection").(bool),
+		Hostname:           d.Get("hostname").(string),
 		ForceSendFields:    []string{"CanIpForward", "DeletionProtection"},
 	}, nil
 }
@@ -892,6 +899,7 @@ func resourceComputeInstanceRead(d *schema.ResourceData, meta interface{}) error
 	d.Set("project", project)
 	d.Set("zone", GetResourceNameFromSelfLink(instance.Zone))
 	d.Set("name", instance.Name)
+	d.Set("hostname", instance.Hostname)
 	d.SetId(instance.Name)
 
 	return nil

google/resource_compute_instance_test.go

@@ -1043,6 +1043,26 @@ func TestAccComputeInstance_secondaryAliasIpRange(t *testing.T) {
 	})
 }
 
+func TestAccComputeInstance_hostname(t *testing.T) {
+	t.Parallel()
+
+	var instanceName = fmt.Sprintf("instance-test-%s", acctest.RandString(10))
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testAccCheckComputeInstanceDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccComputeInstance_hostname(instanceName),
+				Check: resource.ComposeTestCheckFunc(
+					resource.TestCheckResourceAttrSet("google_compute_instance.foobar", "hostname"),
+				),
+			},
+			computeInstanceImportStep("us-central1-a", instanceName, []string{}),
+		},
+	})
+}
+
 func testAccCheckComputeInstanceUpdateMachineType(n string) resource.TestCheckFunc {
 	return func(s *terraform.State) error {
 		rs, ok := s.RootModule().Resources[n]
@@ -2908,6 +2928,33 @@ resource "google_compute_instance" "foobar" {
 }`, network, subnet, instance)
 }
 
+func testAccComputeInstance_hostname(instance string) string {
+	return fmt.Sprintf(`
+data "google_compute_image" "my_image" {
+	family  = "debian-9"
+	project = "debian-cloud"
+}
+
+resource "google_compute_instance" "foobar" {
+	name           = "%s"
+	machine_type   = "n1-standard-1"
+	zone           = "us-central1-a"
+	can_ip_forward = false
+
+	boot_disk {
+		initialize_params{
+			image = "${data.google_compute_image.my_image.self_link}"
+		}
+	}
+
+	network_interface {
+		network = "default"
+	}
+
+	hostname = "%s.test"
+}`, instance, instance)
+}
+
 // Set fields that require stopping the instance: machine_type, min_cpu_platform, and service_account
 func testAccComputeInstance_stopInstanceToUpdate(instance string) string {
 	return fmt.Sprintf(`

website/docs/r/compute_instance.html.markdown

@@ -94,6 +94,10 @@ The following arguments are supported:
 * `deletion_protection` - (Optional) Enable deletion protection on this instance. Defaults to false.
     **Note:** you must disable deletion protection before removing the resource (e.g., via `terraform destroy`), or the instance cannot be deleted and the Terraform run will not complete successfully.
 
+* `hostname` - (Optional) A custom hostname for the instance. Must be a fully qualified DNS name and RFC-1035-valid.
+  Valid format is a series of labels 1-63 characters long matching the regular expression `[a-z]([-a-z0-9]*[a-z0-9])`, concatenated with periods.
+  The entire hostname must not exceed 253 characters. Changing this forces a new resource to be created.
+
 * `guest_accelerator` - (Optional) List of the type and count of accelerator cards attached to the instance. Structure documented below.
     **Note:** GPU accelerators can only be used with [`on_host_maintenance`](#on_host_maintenance) option set to TERMINATE.