Create a VM instance from an instance template with overrides

Create a VM instance from an instance template, then override the disk and machine type options in the template.

Explore further

For detailed documentation that includes this code sample, see the following:

• Create a VM from an instance template

Code sample

Go

Before trying this sample, follow the Go setup instructions in the Compute Engine quickstart using client libraries. For more information, see the Compute Engine Go API reference documentation.

To authenticate to Compute Engine, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

import (
	"context"
	"fmt"
	"io"

	compute "cloud.google.com/go/compute/apiv1"
	computepb "cloud.google.com/go/compute/apiv1/computepb"

	"google.golang.org/protobuf/proto"
)

// createInstanceFromTemplate creates a Compute Engine VM instance from an instance template, but overrides the disk and machine type options in the template.
func createInstanceFromTemplateWithOverrides(w io.Writer, projectID, zone, instanceName, instanceTemplateName, machineType, newDiskSourceImage string) error {
	// projectID := "your_project_id"
	// zone := "europe-central2-b"
	// instanceName := "your_instance_name"
	// instanceTemplateName := "your_instance_template_name"
	// machineType := "n1-standard-2"
	// newDiskSourceImage := "projects/debian-cloud/global/images/family/debian-12"

	ctx := context.Background()
	instancesClient, err := compute.NewInstancesRESTClient(ctx)
	if err != nil {
		return fmt.Errorf("NewInstancesRESTClient: %w", err)
	}
	defer instancesClient.Close()

	intanceTemplatesClient, err := compute.NewInstanceTemplatesRESTClient(ctx)
	if err != nil {
		return fmt.Errorf("NewInstanceTemplatesRESTClient: %w", err)
	}
	defer intanceTemplatesClient.Close()

	// Retrieve an instance template by name.
	reqGetTemplate := &computepb.GetInstanceTemplateRequest{
		Project:          projectID,
		InstanceTemplate: instanceTemplateName,
	}

	instanceTemplate, err := intanceTemplatesClient.Get(ctx, reqGetTemplate)
	if err != nil {
		return fmt.Errorf("unable to get intance template: %w", err)
	}

	for _, disk := range instanceTemplate.Properties.Disks {
		diskType := disk.InitializeParams.GetDiskType()
		if diskType != "" {
			disk.InitializeParams.DiskType = proto.String(fmt.Sprintf(`zones/%s/diskTypes/%s`, zone, diskType))
		}
	}

	reqInsertInstance := &computepb.InsertInstanceRequest{
		Project: projectID,
		Zone:    zone,
		InstanceResource: &computepb.Instance{
			Name:        proto.String(instanceName),
			MachineType: proto.String(fmt.Sprintf(`zones/%s/machineTypes/%s`, zone, machineType)),
			Disks: append(
				// If you override a repeated field, all repeated values
				// for that property are replaced with the
				// corresponding values provided in the request.
				// When adding a new disk to existing disks,
				// insert all existing disks as well.
				instanceTemplate.Properties.Disks,
				&computepb.AttachedDisk{
					InitializeParams: &computepb.AttachedDiskInitializeParams{
						DiskSizeGb:  proto.Int64(10),
						SourceImage: &newDiskSourceImage,
					},
					AutoDelete: proto.Bool(true),
					Boot:       proto.Bool(false),
					Type:       proto.String(computepb.AttachedDisk_PERSISTENT.String()),
				},
			),
		},
		SourceInstanceTemplate: instanceTemplate.SelfLink,
	}

	op, err := instancesClient.Insert(ctx, reqInsertInstance)
	if err != nil {
		return fmt.Errorf("unable to create instance: %w", err)
	}

	if err = op.Wait(ctx); err != nil {
		return fmt.Errorf("unable to wait for the operation: %w", err)
	}

	fmt.Fprintf(w, "Instance created\n")

	return nil
}

Java

Before trying this sample, follow the Java setup instructions in the Compute Engine quickstart using client libraries. For more information, see the Compute Engine Java API reference documentation.

To authenticate to Compute Engine, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

import com.google.cloud.compute.v1.AttachedDisk;
import com.google.cloud.compute.v1.AttachedDiskInitializeParams;
import com.google.cloud.compute.v1.InsertInstanceRequest;
import com.google.cloud.compute.v1.Instance;
import com.google.cloud.compute.v1.InstanceTemplate;
import com.google.cloud.compute.v1.InstanceTemplatesClient;
import com.google.cloud.compute.v1.InstancesClient;
import com.google.cloud.compute.v1.Operation;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;

public class CreateInstanceFromTemplateWithOverrides {

  public static void main(String[] args)
      throws IOException, ExecutionException, InterruptedException, TimeoutException {
    /* TODO(developer): Replace these variables before running the sample.
     * projectId - ID or number of the project you want to use.
     * zone - Name of the zone you want to check, for example: us-west3-b
     * instanceName - Name of the new instance.
     * instanceTemplateName - Name of the instance template to use when creating the new instance.
     * machineType - Machine type you want to set in following format:
     *    "zones/{zone}/machineTypes/{type_name}". For example:
     *    "zones/europe-west3-c/machineTypes/f1-micro"
     *    You can find the list of available machine types using:
     *    https://cloud.google.com/sdk/gcloud/reference/compute/machine-types/list
     * newDiskSourceImage - Path the the disk image you want to use for your new
     *    disk. This can be one of the public images
     *    (like "projects/debian-cloud/global/images/family/debian-11")
     *    or a private image you have access to.
     *    You can check the list of available public images using the doc:
     *    http://cloud.google.com/compute/docs/images
     */
    String projectId = "your-project-id";
    String zone = "zone-name";
    String instanceName = "instance-name";
    String instanceTemplateName = "instance-template-name";

    createInstanceFromTemplateWithOverrides(projectId, zone, instanceName, instanceTemplateName);
  }

  // Creates a Compute Engine VM instance from an instance template,
  // but overrides the disk and machine type options in the template.
  public static void createInstanceFromTemplateWithOverrides(String projectId, String zone,
      String instanceName, String instanceTemplateName)
      throws IOException, ExecutionException, InterruptedException, TimeoutException {

    try (InstancesClient instancesClient = InstancesClient.create();
        InstanceTemplatesClient instanceTemplatesClient = InstanceTemplatesClient.create()) {

      String machineType = "n1-standard-1";
      String newDiskSourceImage = "projects/debian-cloud/global/images/family/debian-11";

      // Retrieve an instance template.
      InstanceTemplate instanceTemplate = instanceTemplatesClient
          .get(projectId, instanceTemplateName);

      // Adjust diskType field of the instance template to use the URL formatting 
      // required by instances.insert.diskType
      // For instance template, there is only a name, not URL.
      List<AttachedDisk> reformattedAttachedDisks = new ArrayList<>();
      for (AttachedDisk disk : instanceTemplate.getProperties().getDisksList()) {
        disk = AttachedDisk.newBuilder(disk)
            .setInitializeParams(AttachedDiskInitializeParams
                .newBuilder(disk.getInitializeParams())
                .setDiskType(
                    String.format(
                        "zones/%s/diskTypes/%s", zone, disk.getInitializeParams().getDiskType()))
                .build())
            .build();

        reformattedAttachedDisks.add(disk);
      }

      AttachedDisk newdisk = AttachedDisk.newBuilder()
          .setInitializeParams(AttachedDiskInitializeParams.newBuilder()
              .setDiskSizeGb(10)
              .setSourceImage(newDiskSourceImage).build())
          .setAutoDelete(true)
          .setBoot(false)
          .setType(AttachedDisk.Type.PERSISTENT.toString()).build();

      Instance instance = Instance.newBuilder()
          .setName(instanceName)
          .setMachineType(String.format("zones/%s/machineTypes/%s", zone, machineType))
          // If you override a repeated field, all repeated values
          // for that property are replaced with the
          // corresponding values provided in the request.
          // When adding a new disk to existing disks,
          // insert all existing disks as well.
          .addAllDisks(reformattedAttachedDisks)
          .addDisks(newdisk)
          .build();

      InsertInstanceRequest insertInstanceRequest = InsertInstanceRequest.newBuilder()
          .setProject(projectId)
          .setZone(zone)
          .setInstanceResource(instance)
          .setSourceInstanceTemplate(instanceTemplate.getSelfLink()).build();

      Operation response = instancesClient.insertAsync(insertInstanceRequest)
          .get(3, TimeUnit.MINUTES);

      if (response.hasError()) {
        System.out.println("Instance creation from template with overrides failed ! ! " + response);
        return;
      }
      System.out
          .printf("Instance creation from template with overrides: Operation Status %s: %s ",
              instanceName, response.getStatus());
    }

  }
}

Node.js

Before trying this sample, follow the Node.js setup instructions in the Compute Engine quickstart using client libraries. For more information, see the Compute Engine Node.js API reference documentation.

To authenticate to Compute Engine, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

/**
 * TODO(developer): Uncomment and replace these variables before running the sample.
 */
// const projectId = 'YOUR_PROJECT_ID';
// const zone = 'europe-central2-b';
// const instanceName = 'YOUR_INSTANCE_NAME';
// const instanceTemplateName = 'YOUR_INSTANCE_TEMPLATE_NAME';
// const machineType = 'n1-standard-1';
// const newDiskSourceImage = 'projects/debian-cloud/global/images/family/debian-11';

const compute = require('@google-cloud/compute');

// Creates a new instance in the specified project and zone using a selected template,
// but overrides the disk and machine type options in the template.
async function createInstanceFromTemplateWithOverrides() {
  const instancesClient = new compute.InstancesClient();
  const instanceTemplatesClient = new compute.InstanceTemplatesClient();

  console.log(
    `Creating the ${instanceName} instance in ${zone} from template ${instanceTemplateName}...`
  );

  // Retrieve an instance template by name.
  const [instanceTemplate] = await instanceTemplatesClient.get({
    project: projectId,
    instanceTemplate: instanceTemplateName,
  });

  // Adjust diskType field of the instance template to use the URL formatting required by instances.insert.diskType
  // For instance template, there is only a name, not URL.
  for (const disk of instanceTemplate.properties.disks) {
    if (disk.initializeParams.diskType) {
      disk.initializeParams.diskType = `zones/${zone}/diskTypes/${disk.initializeParams.diskType}`;
    }
  }

  const [response] = await instancesClient.insert({
    project: projectId,
    zone,
    instanceResource: {
      name: instanceName,
      machineType: `zones/${zone}/machineTypes/${machineType}`,
      disks: [
        // If you override a repeated field, all repeated values
        // for that property are replaced with the
        // corresponding values provided in the request.
        // When adding a new disk to existing disks,
        // insert all existing disks as well.
        ...instanceTemplate.properties.disks,
        {
          initializeParams: {
            diskSizeGb: '10',
            sourceImage: newDiskSourceImage,
          },
          autoDelete: true,
          boot: false,
          type: 'PERSISTENT',
        },
      ],
    },
    sourceInstanceTemplate: instanceTemplate.selfLink,
  });
  let operation = response.latestResponse;
  const operationsClient = new compute.ZoneOperationsClient();

  // Wait for the create operation to complete.
  while (operation.status !== 'DONE') {
    [operation] = await operationsClient.wait({
      operation: operation.name,
      project: projectId,
      zone: operation.zone.split('/').pop(),
    });
  }

  console.log('Instance created.');
}

createInstanceFromTemplateWithOverrides();

Python

Before trying this sample, follow the Python setup instructions in the Compute Engine quickstart using client libraries. For more information, see the Compute Engine Python API reference documentation.

To authenticate to Compute Engine, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

from __future__ import annotations

import sys
from typing import Any

from google.api_core.extended_operation import ExtendedOperation
from google.cloud import compute_v1


def wait_for_extended_operation(
    operation: ExtendedOperation, verbose_name: str = "operation", timeout: int = 300
) -> Any:
    """
    Waits for the extended (long-running) operation to complete.

    If the operation is successful, it will return its result.
    If the operation ends with an error, an exception will be raised.
    If there were any warnings during the execution of the operation
    they will be printed to sys.stderr.

    Args:
        operation: a long-running operation you want to wait on.
        verbose_name: (optional) a more verbose name of the operation,
            used only during error and warning reporting.
        timeout: how long (in seconds) to wait for operation to finish.
            If None, wait indefinitely.

    Returns:
        Whatever the operation.result() returns.

    Raises:
        This method will raise the exception received from `operation.exception()`
        or RuntimeError if there is no exception set, but there is an `error_code`
        set for the `operation`.

        In case of an operation taking longer than `timeout` seconds to complete,
        a `concurrent.futures.TimeoutError` will be raised.
    """
    result = operation.result(timeout=timeout)

    if operation.error_code:
        print(
            f"Error during {verbose_name}: [Code: {operation.error_code}]: {operation.error_message}",
            file=sys.stderr,
            flush=True,
        )
        print(f"Operation ID: {operation.name}", file=sys.stderr, flush=True)
        raise operation.exception() or RuntimeError(operation.error_message)

    if operation.warnings:
        print(f"Warnings during {verbose_name}:\n", file=sys.stderr, flush=True)
        for warning in operation.warnings:
            print(f" - {warning.code}: {warning.message}", file=sys.stderr, flush=True)

    return result


def create_instance_from_template_with_overrides(
    project_id: str,
    zone: str,
    instance_name: str,
    instance_template_name: str,
    machine_type: str,
    new_disk_source_image: str,
) -> compute_v1.Instance:
    """
    Creates a Compute Engine VM instance from an instance template, changing the machine type and
    adding a new disk created from a source image.

    Args:
        project_id: ID or number of the project you want to use.
        zone: Name of the zone you want to check, for example: us-west3-b
        instance_name: Name of the new instance.
        instance_template_name: Name of the instance template used for creating the new instance.
        machine_type: Machine type you want to set in following format:
            "zones/{zone}/machineTypes/{type_name}". For example:
            - "zones/europe-west3-c/machineTypes/f1-micro"
            - You can find the list of available machine types using:
              https://cloud.google.com/sdk/gcloud/reference/compute/machine-types/list
        new_disk_source_image: Path the the disk image you want to use for your new
            disk. This can be one of the public images
            (like "projects/debian-cloud/global/images/family/debian-12")
            or a private image you have access to.
            For a list of available public images, see the documentation:
            http://cloud.google.com/compute/docs/images

    Returns:
        Instance object.
    """
    instance_client = compute_v1.InstancesClient()
    instance_template_client = compute_v1.InstanceTemplatesClient()

    # Retrieve an instance template by name.
    instance_template = instance_template_client.get(
        project=project_id, instance_template=instance_template_name
    )

    # Adjust diskType field of the instance template to use the URL formatting required by instances.insert.diskType
    # For instance template, there is only a name, not URL.
    for disk in instance_template.properties.disks:
        if disk.initialize_params.disk_type:
            disk.initialize_params.disk_type = (
                f"zones/{zone}/diskTypes/{disk.initialize_params.disk_type}"
            )

    instance = compute_v1.Instance()
    instance.name = instance_name
    instance.machine_type = machine_type
    instance.disks = list(instance_template.properties.disks)

    new_disk = compute_v1.AttachedDisk()
    new_disk.initialize_params.disk_size_gb = 50
    new_disk.initialize_params.source_image = new_disk_source_image
    new_disk.auto_delete = True
    new_disk.boot = False
    new_disk.type_ = "PERSISTENT"

    instance.disks.append(new_disk)

    instance_insert_request = compute_v1.InsertInstanceRequest()
    instance_insert_request.project = project_id
    instance_insert_request.zone = zone
    instance_insert_request.instance_resource = instance
    instance_insert_request.source_instance_template = instance_template.self_link

    operation = instance_client.insert(instance_insert_request)
    wait_for_extended_operation(operation, "instance creation")

    return instance_client.get(project=project_id, zone=zone, instance=instance_name)

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