You create a virtual machine (VM) instance from either an OS image or a disk image. This document shows you how to determine the source OS image or source disk image of a VM.
Before you begin
- If you haven't already, set up authentication 
.
  Authentication verifies your identity for access to Google Cloud services and APIs. To run
  code or samples from a local development environment, you can authenticate to
  Compute Engine by selecting one of the following options: Select the tab for how you plan to use the samples on this page: ConsoleWhen you use the Google Cloud console to access Google Cloud services and APIs, you don't need to set up authentication. gcloud-  Install the Google Cloud CLI. After installation, initialize the Google Cloud CLI by running the following command: gcloud init If you're using an external identity provider (IdP), you must first sign in to the gcloud CLI with your federated identity . 
- Set a default region and zone .
 RESTTo use the REST API samples on this page in a local development environment, you use the credentials you provide to the gcloud CLI. Install the Google Cloud CLI. After installation, initialize the Google Cloud CLI by running the following command: gcloud init If you're using an external identity provider (IdP), you must first sign in to the gcloud CLI with your federated identity . For more information, see Authenticate for using REST in the Google Cloud authentication documentation. 
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View the source OS image or source disk image of a VM
To view the source OS image or source disk image of a VM, use the Google Cloud console, Google Cloud CLI, or Compute Engine API.
Console
-  In the Google Cloud console, go to the VM instancespage. 
-  Click the Nameof the VM. 
-  The name of the source OS image or source disk image is in Storage > Boot disk > Image. 
gcloud
-  View the disks attached to a VM by using the following gcloud compute instances describecommand :gcloud compute instances describe VM_NAMEReplace VM_NAMEwith the name of the VM.
-  View the source OS image or source disk image of the disk by using the following gcloud compute disks describecommand :gcloud compute disks describe DISK_NAME \ --zone= ZONE \ --format="get( SOURCE )" Replace the following: -  DISK_NAME: the name of the disk to view the source of.
-  ZONE: the zone that the disk is located in.
-  SOURCE: a value that specifies whether to return the source OS image or the source disk image. Set tosourceDiskor tosourceImage. No value is returned when specifyingsourceDiskorsourceImageunless there is a corresponding source OS image or a source disk image. If no value is returned, specify the other value and run the command again.
 
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REST
-  View the disks attached to a VM by using the following instances.getmethod :GET https://compute.googleapis.com/compute/v1/projects/ PROJECT_ID /zones/ ZONE /instances/ VM_NAME Replace the following: -  PROJECT_ID: the project ID
-  ZONE: the zone containing the VM
-  VM_NAME: the name of the VM
 
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-  View the source OS image or source disk image of the disk by using the disks.getmethod .For a VM that has a source OS image, this method returns the source image that was used to create the disk in the sourceImagefield. For a VM that has a source disk image, this method instead returns the source image in thesourceDiskfield.GET https://compute.googleapis.com/compute/v1/projects/ PROJECT_ID /zones/ ZONE /disks/ DISK_NAME Replace the following: -  PROJECT_ID: the project ID
-  ZONE: the zone containing the disk
-  DISK_NAME: the name of the disk
 
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What's next
- Learn more about OS images on Compute Engine.

