Create a VM from an instance template

This page explains how to use aninstance templateto create a VM instance. An instance template is an API resource that definesthe properties of VM instances. You define properties like the machine type,OS image, persistent disk configurations, metadata, startup scripts, and so on,in an instance template and then can use the instance template to createindividual VM instances orgroups of managed instances.

When you create a VM instance from an instance template, the default behavioris to create a VM instance that is identical to the properties specifiedin the template, with the exception of the VM instance name and the zone wherethe instance will live. Alternatively, you can also optionally override certainfields during instance creation if you want to change certain propertiesof the instance template for specific uses.

This document assumes that you have an instance template ready to use. If youdo not have an instance template, follow the instructions tocreate a new instance template.

Before you begin

Create a VM instance from an instance template

You can use either a regional or a global instance template to create a VMinstance. To create an instance exactly as described in the instance template,follow these instructions.

Console

  1. In the Google Cloud console, go to theCreate an instance page.

    Go to Create an instance

  2. In theCreate VM from ... menu, selectInstance templates.

  3. In theCreate VM from template window that appears, do the following:

    1. Select a template.

    2. To create and start the VM, clickCreate.

gcloud

To create a VM from a regional or global instance template, use the samegcloud compute instances create commandthat you would use to create a normal instance, but add the--source-instance-template flag:

gcloud compute instances createVM_NAME \    --source-instance-templateINSTANCE_TEMPLATE_URL

Replace the following:

  • VM_NAME: thename of the instance.
  • INSTANCE_TEMPLATE_URL: the URL of the instance template that you want touse to create VMs in the MIG. The URL can contain either theIDor name of the instance template. Specify one of the following values:
    • For a regional instance template:projects/PROJECT_ID/regions/REGION/instanceTemplates/INSTANCE_TEMPLATE_ID
    • For a global instance template:INSTANCE_TEMPLATE_ID

For example:

gcloud compute instances create example-instance \    --source-instance-template 1234567890

Go

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.funccreateInstanceFromTemplate(wio.Writer,projectID,zone,instanceName,instanceTemplateUrlstring)error{// projectID := "your_project_id"// zone := "europe-central2-b"// instanceName := "your_instance_name"// instanceTemplateUrl := "global/instanceTemplates/your_instance_template"ctx:=context.Background()instancesClient,err:=compute.NewInstancesRESTClient(ctx)iferr!=nil{returnfmt.Errorf("NewInstancesRESTClient: %w",err)}deferinstancesClient.Close()req:=&computepb.InsertInstanceRequest{Project:projectID,Zone:zone,InstanceResource:&computepb.Instance{Name:proto.String(instanceName),},SourceInstanceTemplate:&instanceTemplateUrl,}op,err:=instancesClient.Insert(ctx,req)iferr!=nil{returnfmt.Errorf("unable to create instance: %w",err)}iferr=op.Wait(ctx);err!=nil{returnfmt.Errorf("unable to wait for the operation: %w",err)}fmt.Fprintf(w,"Instance created\n")returnnil}

Java

importcom.google.cloud.compute.v1.AttachedDisk;importcom.google.cloud.compute.v1.AttachedDiskInitializeParams;importcom.google.cloud.compute.v1.InsertInstanceRequest;importcom.google.cloud.compute.v1.Instance;importcom.google.cloud.compute.v1.InstanceProperties;importcom.google.cloud.compute.v1.InstanceTemplate;importcom.google.cloud.compute.v1.InstanceTemplatesClient;importcom.google.cloud.compute.v1.InstancesClient;importcom.google.cloud.compute.v1.Operation;importjava.io.IOException;importjava.util.ArrayList;importjava.util.List;importjava.util.concurrent.ExecutionException;importjava.util.concurrent.TimeUnit;importjava.util.concurrent.TimeoutException;publicclassCreateInstanceFromTemplate{publicstaticvoidmain(String[]args)throwsIOException,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.        instanceTemplateURL - URL of the instance template using for creating the new instance.        It can be a full or partial URL.        Examples:        - https://www.googleapis.com/compute/v1/projects/project/global/instanceTemplates/example-instance-template        - projects/project/global/instanceTemplates/example-instance-template        - global/instanceTemplates/example-instance-template     */StringprojectId="your-project-id";Stringzone="zone-name";StringinstanceName="instance-name";StringinstanceTemplateUrl="instance-template-url";createInstanceFromTemplate(projectId,zone,instanceName,instanceTemplateUrl);}// Create a new instance from template in the specified project and zone.publicstaticvoidcreateInstanceFromTemplate(StringprojectId,Stringzone,StringinstanceName,StringinstanceTemplateName)throwsIOException,ExecutionException,InterruptedException,TimeoutException{try(InstancesClientinstancesClient=InstancesClient.create();InstanceTemplatesClientinstanceTemplatesClient=InstanceTemplatesClient.create()){InstanceTemplateinstanceTemplate=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=newArrayList<>();for(AttachedDiskdisk: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);}// Clear existing disks and set the reformatted disks in the instance template.instanceTemplate=InstanceTemplate.newBuilder(instanceTemplate).setProperties(InstanceProperties.newBuilder(instanceTemplate.getProperties()).clearDisks().addAllDisks(reformattedAttachedDisks).build()).build();InsertInstanceRequestinsertInstanceRequest=InsertInstanceRequest.newBuilder().setProject(projectId).setZone(zone).setInstanceResource(Instance.newBuilder().setName(instanceName).build()).setSourceInstanceTemplate(instanceTemplate.getSelfLink()).build();Operationresponse=instancesClient.insertAsync(insertInstanceRequest).get(3,TimeUnit.MINUTES);if(response.hasError()){System.out.println("Instance creation from template failed ! ! "+response);return;}System.out.printf("Instance creation from template: Operation Status %s: %s ",instanceName,response.getStatus());}}}

Node.js

/** * 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 instanceTemplateUrl = 'YOUR_INSTANCE_TEMPLATE_URL'constcompute=require('@google-cloud/compute');// Create a new instance from template in the specified project and zone.asyncfunctioncreateInstanceFromTemplate(){constinstancesClient=newcompute.InstancesClient();console.log(`Creating the${instanceName} instance in${zone} from template${instanceTemplateUrl}...`);const[response]=awaitinstancesClient.insert({project:projectId,zone,instanceResource:{name:instanceName,},sourceInstanceTemplate:instanceTemplateUrl,});letoperation=response.latestResponse;constoperationsClient=newcompute.ZoneOperationsClient();// Wait for the create operation to complete.while(operation.status!=='DONE'){[operation]=awaitoperationsClient.wait({operation:operation.name,project:projectId,zone:operation.zone.split('/').pop(),});}console.log('Instance created.');}createInstanceFromTemplate();

Python

from__future__importannotationsimportsysfromtypingimportAnyfromgoogle.api_core.extended_operationimportExtendedOperationfromgoogle.cloudimportcompute_v1defwait_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)ifoperation.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)raiseoperation.exception()orRuntimeError(operation.error_message)ifoperation.warnings:print(f"Warnings during{verbose_name}:\n",file=sys.stderr,flush=True)forwarninginoperation.warnings:print(f" -{warning.code}:{warning.message}",file=sys.stderr,flush=True)returnresultdefcreate_instance_from_template(project_id:str,zone:str,instance_name:str,instance_template_url:str)->compute_v1.Instance:"""    Creates a Compute Engine VM instance from an instance template.    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_url: URL of the instance template used for creating the new instance.            It can be a full or partial URL.            Examples:            - https://www.googleapis.com/compute/v1/projects/project/global/instanceTemplates/example-instance-template            - projects/project/global/instanceTemplates/example-instance-template            - global/instanceTemplates/example-instance-template    Returns:        Instance object.    """instance_client=compute_v1.InstancesClient()instance_insert_request=compute_v1.InsertInstanceRequest()instance_insert_request.project=project_idinstance_insert_request.zone=zoneinstance_insert_request.source_instance_template=instance_template_urlinstance_insert_request.instance_resource.name=instance_nameoperation=instance_client.insert(instance_insert_request)wait_for_extended_operation(operation,"instance creation")returninstance_client.get(project=project_id,zone=zone,instance=instance_name)

REST

To create a VM from a regional or global instance template, construct anormal request tocreate an instancebut include thesourceInstanceTemplatequery parameter followed by a qualified path to an instance template.

POST https://compute.googleapis.com/compute/v1/projects/PROJECT_ID/zones/ZONE/instances?sourceInstanceTemplate=INSTANCE_TEMPLATE_URL

In the request body, provide aname for the VM instance:

{ "name": "example-instance" }

For example, the following snippet includes a fully-qualified path to thetemplate:https://compute.googleapis.com/compute/v1/projects/myproject/global/instanceTemplates/1234567890.

POST https://compute.googleapis.com/compute/v1/projects/myproject/zones/us-central1-a/instances?sourceInstanceTemplate=https://compute.googleapis.com/compute/v1/projects/myproject/global/instanceTemplates/1234567890
{ "name": "example-instance" }

Create a VM instance from an instance template with overrides

When you use an instance template to start a VM instance, the default behavioris to create a VM instance exactly as described in the instance template withthe exception of the instance name and zone.

If you want to create an instance primarily based on an instance templatebut with a few changes, you can use the override behavior. To use theoverride behavior, you pass in attributes to override for the existing instancetemplate when creating the instance.

Console

  1. In the Google Cloud console, go to theCreate an instance page.

    Go to Create an instance

  2. In theCreate VM from ... menu, selectInstance templates.

  3. In theCreate VM from template window that appears, select atemplate, and then clickCustomize.

  4. Optional: Specify other configuration options. For more information, seeConfiguration options during instance creation.

  5. To create and start the instance, clickCreate.

gcloud

Using the gcloud CLI, make a request to create an instance withthe--source-instance-template flag and override any property you wantwith the appropriategcloud flag. To see a list of applicable flags,review thegcloud reference.

For example, provide the following flags to override the machine type,metadata, operating system, Persistent Disk boot disk, and a secondary diskof an instance template:

gcloud compute instances create example-instance \    --source-instance-template 1234567890 --machine-type e2-standard-2 \    --image-family debian-9 --image-project debian-cloud \    --metadata bread=butter --disk=boot=no,name=my-override-disk

Go

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.funccreateInstanceFromTemplateWithOverrides(wio.Writer,projectID,zone,instanceName,instanceTemplateName,machineType,newDiskSourceImagestring)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)iferr!=nil{returnfmt.Errorf("NewInstancesRESTClient: %w",err)}deferinstancesClient.Close()intanceTemplatesClient,err:=compute.NewInstanceTemplatesRESTClient(ctx)iferr!=nil{returnfmt.Errorf("NewInstanceTemplatesRESTClient: %w",err)}deferintanceTemplatesClient.Close()// Retrieve an instance template by name.reqGetTemplate:=&computepb.GetInstanceTemplateRequest{Project:projectID,InstanceTemplate:instanceTemplateName,}instanceTemplate,err:=intanceTemplatesClient.Get(ctx,reqGetTemplate)iferr!=nil{returnfmt.Errorf("unable to get intance template: %w",err)}for_,disk:=rangeinstanceTemplate.Properties.Disks{diskType:=disk.InitializeParams.GetDiskType()ifdiskType!=""{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)iferr!=nil{returnfmt.Errorf("unable to create instance: %w",err)}iferr=op.Wait(ctx);err!=nil{returnfmt.Errorf("unable to wait for the operation: %w",err)}fmt.Fprintf(w,"Instance created\n")returnnil}

Java

importcom.google.cloud.compute.v1.AttachedDisk;importcom.google.cloud.compute.v1.AttachedDiskInitializeParams;importcom.google.cloud.compute.v1.InsertInstanceRequest;importcom.google.cloud.compute.v1.Instance;importcom.google.cloud.compute.v1.InstanceTemplate;importcom.google.cloud.compute.v1.InstanceTemplatesClient;importcom.google.cloud.compute.v1.InstancesClient;importcom.google.cloud.compute.v1.Operation;importjava.io.IOException;importjava.util.ArrayList;importjava.util.List;importjava.util.concurrent.ExecutionException;importjava.util.concurrent.TimeUnit;importjava.util.concurrent.TimeoutException;publicclassCreateInstanceFromTemplateWithOverrides{publicstaticvoidmain(String[]args)throwsIOException,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     */StringprojectId="your-project-id";Stringzone="zone-name";StringinstanceName="instance-name";StringinstanceTemplateName="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.publicstaticvoidcreateInstanceFromTemplateWithOverrides(StringprojectId,Stringzone,StringinstanceName,StringinstanceTemplateName)throwsIOException,ExecutionException,InterruptedException,TimeoutException{try(InstancesClientinstancesClient=InstancesClient.create();InstanceTemplatesClientinstanceTemplatesClient=InstanceTemplatesClient.create()){StringmachineType="n1-standard-1";StringnewDiskSourceImage="projects/debian-cloud/global/images/family/debian-11";// Retrieve an instance template.InstanceTemplateinstanceTemplate=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=newArrayList<>();for(AttachedDiskdisk: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);}AttachedDisknewdisk=AttachedDisk.newBuilder().setInitializeParams(AttachedDiskInitializeParams.newBuilder().setDiskSizeGb(10).setSourceImage(newDiskSourceImage).build()).setAutoDelete(true).setBoot(false).setType(AttachedDisk.Type.PERSISTENT.toString()).build();Instanceinstance=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();InsertInstanceRequestinsertInstanceRequest=InsertInstanceRequest.newBuilder().setProject(projectId).setZone(zone).setInstanceResource(instance).setSourceInstanceTemplate(instanceTemplate.getSelfLink()).build();Operationresponse=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

/** * 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';constcompute=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.asyncfunctioncreateInstanceFromTemplateWithOverrides(){constinstancesClient=newcompute.InstancesClient();constinstanceTemplatesClient=newcompute.InstanceTemplatesClient();console.log(`Creating the${instanceName} instance in${zone} from template${instanceTemplateName}...`);// Retrieve an instance template by name.const[instanceTemplate]=awaitinstanceTemplatesClient.get({project:projectId,instanceTemplate:instanceTemplateName,});// Adjust diskType field of the instance template to use the URL formatting required by instances.insert.diskType// For instance template, there is only a name, not URL.for(constdiskofinstanceTemplate.properties.disks){if(disk.initializeParams.diskType){disk.initializeParams.diskType=`zones/${zone}/diskTypes/${disk.initializeParams.diskType}`;}}const[response]=awaitinstancesClient.insert({project:projectId,zone,instanceResource:{name:instanceName,machineType:`zones/${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,});letoperation=response.latestResponse;constoperationsClient=newcompute.ZoneOperationsClient();// Wait for the create operation to complete.while(operation.status!=='DONE'){[operation]=awaitoperationsClient.wait({operation:operation.name,project:projectId,zone:operation.zone.split('/').pop(),});}console.log('Instance created.');}createInstanceFromTemplateWithOverrides();

Python

from__future__importannotationsimportsysfromtypingimportAnyfromgoogle.api_core.extended_operationimportExtendedOperationfromgoogle.cloudimportcompute_v1defwait_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)ifoperation.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)raiseoperation.exception()orRuntimeError(operation.error_message)ifoperation.warnings:print(f"Warnings during{verbose_name}:\n",file=sys.stderr,flush=True)forwarninginoperation.warnings:print(f" -{warning.code}:{warning.message}",file=sys.stderr,flush=True)returnresultdefcreate_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.fordiskininstance_template.properties.disks:ifdisk.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_nameinstance.machine_type=machine_typeinstance.disks=list(instance_template.properties.disks)new_disk=compute_v1.AttachedDisk()new_disk.initialize_params.disk_size_gb=50new_disk.initialize_params.source_image=new_disk_source_imagenew_disk.auto_delete=Truenew_disk.boot=Falsenew_disk.type_="PERSISTENT"instance.disks.append(new_disk)instance_insert_request=compute_v1.InsertInstanceRequest()instance_insert_request.project=project_idinstance_insert_request.zone=zoneinstance_insert_request.instance_resource=instanceinstance_insert_request.source_instance_template=instance_template.self_linkoperation=instance_client.insert(instance_insert_request)wait_for_extended_operation(operation,"instance creation")returninstance_client.get(project=project_id,zone=zone,instance=instance_name)

REST

In the API, use thesourceInstanceTemplatequery parameter and provide any fields you want to override in the requestbody when constructing a normal request tocreate an instance.

The override behavior in the API follows the JSON merge patch rules,described byRFC 7396.

Specifically:

  • If you override a basic field, the corresponding basic fieldin the instance template will be replaced with the basic field valuein the request. Basic fields includemachineType,sourceImage,name, and so on.
  • If you override a repeated field, all repeated values for that propertywill be replaced with the corresponding values provided in the request.Repeated fields are generally properties of typelist. For example,disks andnetworkInterfaces are repeated fields.
  • If you override anested object, the object in the instancetemplate will be merged with the corresponding object specification inthe request. Note that if a nested object lives within a repeated field,the field is treated according to rules for repeated fields. Labels arean exception to this rule, and are treated as a repeated field eventhough it is of typeobject.

For example, let's assume you have an instance template with two non-bootdisks but you want to override one of the disks. You must provide the entiredisks specification in your request, including any disks you want to keep.

The URL for this request:

POST https://compute.googleapis.com/compute/v1/projects/myproject/zones/us-central1-a/instances?sourceInstanceTemplate=https://compute.googleapis.com/compute/v1/projects/myproject/global/instanceTemplates/1234567890

The request body:

    {      "disks": [        {          # Since you are overriding the repeated disk property, you must          # specify a boot disk in the request, even if it is already          # specified in the instance template          "autoDelete": true,          "boot": true,          "initializeParams": {            "sourceImage": "projects/debian-cloud/global/images/family/debian-8"          },          "mode": "READ_WRITE",          "type": "PERSISTENT"        },        {          # New disk you want to use          "autoDelete": false,          "boot": false,          "mode": "READ_WRITE",          "source": "zones/us-central1-f/disks/my-override-disk",          "type": "PERSISTENT"        },        {           # Assume this disk is already specified in instance template, but           # you must specify it again since you are overriding the disks           # property          "autoDelete": false,          "boot": false,          "mode": "READ_WRITE",          "source": "zones/us-central1-f/disks/my-other-disk-to-keep",          "type": "PERSISTENT"        }      ],      "machineType": "zones/us-central1-f/machineTypes/e2-standard-2",      "name": "example-instance"    }

What's next

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Last updated 2025-07-16 UTC.