provider/azurerm: Add support for setting the primary network interface

builtin/providers/azurerm/resource_arm_virtual_machine.go

@@ -434,6 +434,11 @@ func resourceArmVirtualMachine() *schema.Resource {
 				Set: schema.HashString,
 			},
 
+			"primary_network_interface_id": {
+				Type:     schema.TypeString,
+				Optional: true,
+			},
+
 			"tags": tagsSchema(),
 		},
 	}
@@ -648,6 +653,15 @@ func resourceArmVirtualMachineRead(d *schema.ResourceData, meta interface{}) err
 		if err := d.Set("network_interface_ids", flattenAzureRmVirtualMachineNetworkInterfaces(resp.VirtualMachineProperties.NetworkProfile)); err != nil {
 			return fmt.Errorf("[DEBUG] Error setting Virtual Machine Storage Network Interfaces: %#v", err)
 		}
+
+		if resp.VirtualMachineProperties.NetworkProfile.NetworkInterfaces != nil {
+			for _, nic := range *resp.VirtualMachineProperties.NetworkProfile.NetworkInterfaces {
+				if nic.NetworkInterfaceReferenceProperties != nil && *nic.NetworkInterfaceReferenceProperties.Primary {
+					d.Set("primary_network_interface_id", nic.ID)
+					break
+				}
+			}
+		}
 	}
 
 	flattenAndSetTags(d, resp.Tags)
@@ -1275,14 +1289,20 @@ func expandAzureRmVirtualMachineImageReference(d *schema.ResourceData) (*compute
 
 func expandAzureRmVirtualMachineNetworkProfile(d *schema.ResourceData) compute.NetworkProfile {
 	nicIds := d.Get("network_interface_ids").(*schema.Set).List()
+	primaryNicId := d.Get("primary_network_interface_id").(string)
 	network_interfaces := make([]compute.NetworkInterfaceReference, 0, len(nicIds))
 
 	network_profile := compute.NetworkProfile{}
 
 	for _, nic := range nicIds {
 		id := nic.(string)
+		primary := id == primaryNicId
+
 		network_interface := compute.NetworkInterfaceReference{
 			ID: &id,
+			NetworkInterfaceReferenceProperties: &compute.NetworkInterfaceReferenceProperties{
+				Primary: &primary,
+			},
 		}
 		network_interfaces = append(network_interfaces, network_interface)
 	}

builtin/providers/azurerm/resource_arm_virtual_machine_test.go

@@ -580,6 +580,25 @@ func TestAccAzureRMVirtualMachine_windowsLicenseType(t *testing.T) {
 	})
 }
 
+func TestAccAzureRMVirtualMachine_primaryNetworkInterfaceId(t *testing.T) {
+	var vm compute.VirtualMachine
+	ri := acctest.RandInt()
+	config := fmt.Sprintf(testAccAzureRMVirtualMachine_primaryNetworkInterfaceId, ri, ri, ri, ri, ri, ri, ri)
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testCheckAzureRMVirtualMachineDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config: config,
+				Check: resource.ComposeTestCheckFunc(
+					testCheckAzureRMVirtualMachineExists("azurerm_virtual_machine.test", &vm),
+				),
+			},
+		},
+	})
+}
+
 var testAccAzureRMVirtualMachine_basicLinuxMachine = `
 resource "azurerm_resource_group" "test" {
     name = "acctestRG-%d"
@@ -2465,3 +2484,105 @@ resource "azurerm_virtual_machine" "test" {
     }
 }
 `
+
+var testAccAzureRMVirtualMachine_primaryNetworkInterfaceId = `
+resource "azurerm_resource_group" "test" {
+    name = "acctestRG-%d"
+    location = "West US"
+}
+
+resource "azurerm_virtual_network" "test" {
+    name = "acctvn-%d"
+    address_space = ["10.0.0.0/16"]
+    location = "West US"
+    resource_group_name = "${azurerm_resource_group.test.name}"
+}
+
+resource "azurerm_subnet" "test" {
+    name = "acctsub-%d"
+    resource_group_name = "${azurerm_resource_group.test.name}"
+    virtual_network_name = "${azurerm_virtual_network.test.name}"
+    address_prefix = "10.0.2.0/24"
+}
+
+resource "azurerm_network_interface" "test" {
+    name = "acctni-%d"
+    location = "West US"
+    resource_group_name = "${azurerm_resource_group.test.name}"
+
+    ip_configuration {
+    	name = "testconfiguration1"
+    	subnet_id = "${azurerm_subnet.test.id}"
+    	private_ip_address_allocation = "dynamic"
+    }
+}
+
+resource "azurerm_network_interface" "test2" {
+    name = "acctni2-%d"
+    location = "West US"
+    resource_group_name = "${azurerm_resource_group.test.name}"
+
+    ip_configuration {
+    	name = "testconfiguration2"
+    	subnet_id = "${azurerm_subnet.test.id}"
+    	private_ip_address_allocation = "dynamic"
+    }
+}
+
+resource "azurerm_storage_account" "test" {
+    name = "accsa%d"
+    resource_group_name = "${azurerm_resource_group.test.name}"
+    location = "westus"
+    account_type = "Standard_LRS"
+
+    tags {
+        environment = "staging"
+    }
+}
+
+resource "azurerm_storage_container" "test" {
+    name = "vhds"
+    resource_group_name = "${azurerm_resource_group.test.name}"
+    storage_account_name = "${azurerm_storage_account.test.name}"
+    container_access_type = "private"
+}
+
+resource "azurerm_virtual_machine" "test" {
+    name = "acctvm-%d"
+    location = "West US"
+    resource_group_name = "${azurerm_resource_group.test.name}"
+    network_interface_ids = ["${azurerm_network_interface.test.id}","${azurerm_network_interface.test2.id}"]
+    primary_network_interface_id = "${azurerm_network_interface.test.id}"
+    vm_size = "Standard_A3"
+
+    storage_image_reference {
+	publisher = "Canonical"
+	offer = "UbuntuServer"
+	sku = "14.04.2-LTS"
+	version = "latest"
+    }
+
+    storage_os_disk {
+        name = "myosdisk1"
+        vhd_uri = "${azurerm_storage_account.test.primary_blob_endpoint}${azurerm_storage_container.test.name}/myosdisk1.vhd"
+        caching = "ReadWrite"
+        create_option = "FromImage"
+        disk_size_gb = "45"
+    }
+
+    os_profile {
+	computer_name = "hostname"
+	admin_username = "testadmin"
+	admin_password = "Password1234!"
+    }
+
+    os_profile_linux_config {
+	disable_password_authentication = false
+    }
+
+    tags {
+    	environment = "Production"
+    	cost-center = "Ops"
+    }
+}
+`

website/source/docs/providers/azurerm/r/virtual_machine.html.markdown

@@ -220,6 +220,7 @@ The following arguments are supported:
 * `os_profile_linux_config` - (Required, when a linux machine) A Linux config block as documented below.
 * `os_profile_secrets` - (Optional) A collection of Secret blocks as documented below.
 * `network_interface_ids` - (Required) Specifies the list of resource IDs for the network interfaces associated with the virtual machine.
+* `primary_network_interface_id` - (Optional) Specifies the resource ID for the primary network interface associated with the virtual machine.
 * `tags` - (Optional) A mapping of tags to assign to the resource.
 
 For more information on the different example configurations, please check out the [azure documentation](https://msdn.microsoft.com/en-us/library/mt163591.aspx#Anchor_2)