Create a VM that uses a user-managed service account (original) (raw)

This document explains how to create a virtual machine (VM) instance that is configured to use a user-managed service account. A service account is a special kind of account typically used by an application or compute workload to make authorized API calls.

Service accounts are needed for scenarios where a workload, such as a custom application, needs to access Google Cloud resources or perform actions without end-user involvement. For more information about when to use service accounts, see Best practices for using service accounts.

If you have applications that need to make calls to Google Cloud APIs, Google recommends that you attach a user-managed service account to the VM on which the application or workload is running. Then, you grant the service account IAM roles, which gives the service account–and, by extension, applications running on the VM–access to Google Cloud resources.

Before you begin

Console

When you use the Google Cloud console to access Google Cloud services and APIs, you don't need to set up authentication.

gcloud

  1. After installing the Google Cloud CLI,initialize it 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.
  2. Set a default region and zone.

Terraform

To use the Terraform samples on this page in a local development environment, install and initialize the gcloud CLI, and then set up Application Default Credentials with your user credentials.

  1. Install the Google Cloud CLI.
  2. If you're using an external identity provider (IdP), you must first sign in to the gcloud CLI with your federated identity.
  3. To initialize the gcloud CLI, run the following command:
    gcloud init
  4. If you're using a local shell, then create local authentication credentials for your user account:
    gcloud auth application-default login
    You don't need to do this if you're using Cloud Shell.
    If an authentication error is returned, and you are using an external identity provider (IdP), confirm that you have signed in to the gcloud CLI with your federated identity.
    For more information, see Set up authentication for a local development environment.

REST

To use the REST API samples on this page in a local development environment, you use the credentials you provide to the gcloud CLI.
After installing the Google Cloud CLI,initialize it 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, seeAuthenticate for using REST in the Google Cloud authentication documentation.

Required roles

To get the permissions that you need to create VMs that use service accounts, ask your administrator to grant you the following IAM roles on the project:

For more information about granting roles, see Manage access to projects, folders, and organizations.

These predefined roles contain the permissions required to create VMs that use service accounts. To see the exact permissions that are required, expand the Required permissions section:

Required permissions

The following permissions are required to create VMs that use service accounts:

You might also be able to get these permissions with custom roles or other predefined roles.

Overview

It is recommended that you configure service accounts for your VMs as follows:

  1. Create a new user-managed service account rather than using the Compute Engine default service account, and grant IAM roles to that service account for only the resources and operations that it needs.
  2. Attach the service account to your VM.
  3. Set the cloud platform (https://www.googleapis.com/auth/cloud-platform) scope on your VM. This allows the VM's service account to call the Google Cloud APIs that it has permission to use.
    • If you specify the service account by using the Google Cloud console, the VM's access scope automatically defaults to the cloud-platform scope.
    • If you specify the service account by using the Google Cloud CLI or Compute Engine API, you can use the scopes parameter to set the access scope.

Set up a service account

Create a service account and assign the required IAM roles. Assign as many or as little IAM roles as needed. You can modify the IAM roles on your service account as needed.

Google recommends that youlimit the privileges of service accountsand regularly check your service account permissions to make sure they are up-to-date.

Use one of the following methods to set up the service account.

Console

In the Google Cloud console, go to the Create service account page.

Go to Create service account

  1. Select your project.
  2. In the Service account name field, enter a name. The Google Cloud console fills in the Service account ID field based on this name.
    In the Service account description field, enter a description. For example,Service account for quickstart.
  3. Click Create and continue.
  4. Grant the required roles to the service account.
    To grant a role, find the Select a role list, then select the role.
    To grant additional roles, click Add another role and add each additional role.
  5. Click Continue.
  6. In the Service account users role field, enter the identifier for the principal that will attach the service account to other resources, such as Compute Engine instances.
    This is typically the email address for a Google Account.
  7. Click Done to finish creating the service account.

gcloud

Set up authentication:

  1. Create the service account:
    gcloud iam service-accounts create SERVICE_ACCOUNT_NAME
    Replace SERVICE_ACCOUNT_NAME with a name for the service account.
  2. To provide access to your project and your resources, grant a role to the service account:
    gcloud projects add-iam-policy-binding PROJECT_ID --member="serviceAccount:SERVICE_ACCOUNT_NAME@PROJECT_ID.iam.gserviceaccount.com" --role=ROLE
    Replace the following:
    • SERVICE_ACCOUNT_NAME: the name of the service account
    • PROJECT_ID: the project ID where you created the service account
    • ROLE: the role to grant
  3. To grant another role to the service account, run the command as you did in the previous step.
  4. Grant the required role to the principal that will attach the service account to other resources.
    gcloud iam service-accounts add-iam-policy-binding SERVICE_ACCOUNT_NAME@PROJECT_ID.iam.gserviceaccount.com --member="user:USER_EMAIL" --role=roles/iam.serviceAccountUser
    Replace the following:
    • SERVICE_ACCOUNT_NAME: the name of the service account
    • PROJECT_ID: the project ID where you created the service account
    • USER_EMAIL: the email address for a Google Account

Terraform

To create a service account, you can use the google_service_accountresource.

Remember to replace the placeholder values for the account_id and thedisplay_name attributes.

To learn how to apply or remove a Terraform configuration, seeBasic Terraform commands.

Create a VM and attach the service account

After you create the service account, create a VM and attach the service account that you created in the previous section. Also set the VM's access scope tocloud-platform.

If you already have an existing VM and you want to configure that VM to use a different service account, seeChange the attached service account.

Use one of the following methods to create a VM and attach the service account.

Console

  1. In the Google Cloud console, go to the Create an instance page.
    Go to Create an instance
  2. To attach a service account, do the following:
    1. In the navigation menu, click Security.
    2. In the Service account list, select the service account that you created.
    3. For Access scopes, selectAllow full access to all Cloud APIs.
  3. Optional: Specify other configuration options. For more information, seeConfiguration options during instance creation.
  4. To create and start the instance, click Create.

gcloud

To create a new VM instance and configure it to use a custom service account by using the Google Cloud CLI, use the gcloud compute instances createcommand and provide the service account email and the cloud-platform access scope to the VM instance.

gcloud compute instances create VM_NAME
--service-account=SERVICE_ACCOUNT_EMAIL
--scopes=https://www.googleapis.com/auth/cloud-platform

Replace the following:

For example:

gcloud compute instances create example-vm
--service-account 123-my-sa@my-project-123.iam.gserviceaccount.com
--scopes=https://www.googleapis.com/auth/cloud-platform

You can also specify the scope using the alias: --scopes=cloud-platform. These aliases are recognized only by the gcloud CLI. The API and other libraries don't recognize these aliases, so you must specify the full scope URI.

Terraform

To set up a new VM to use a service account, you can use thegoogle_compute_instanceresource.

REST

Use the instances.insertmethod to create the VM and specify the service account email and access scope for the VM instance.

POST https://compute.googleapis.com/compute/v1/projects/`PROJECT_ID`/zones/`ZONE`/instances

{ "machineType":"zones/MACHINE_TYPE_ZONE/machineTypes/MACHINE_TYPE", "name":"VM_NAME",

"disks":[ { "initializeParams":{ "sourceImage":"projects/IMAGE_PROJECT/global/images/IMAGE" }, "boot":true } ],

"networkInterfaces":[ { "network":"global/networks/NETWORK_NAME" } ],

"serviceAccounts": [ { "email": "SERVICE_ACCOUNT_EMAIL", "scopes": ["https://www.googleapis.com/auth/cloud-platform"] } ], "shieldedInstanceConfig":{ "enableSecureBoot":"ENABLE_SECURE_BOOT" } }

Replace the following:

Access and use other Google Cloud services

After your VM is configured to use the service account, applications can then use the service account to authenticate. The most common method is to authenticate by usingApplication Default Credentialsand a client library. Some Google Cloud tools such as the gcloud CLI are able to automatically use the service account to access Google Cloud APIs from a VM. For more information, see Authenticate workloads using service accounts.

If a service account is deleted, applications will no longer have access to Google Cloud resources through that service account. If you delete the default App Engine and Compute Engine service accounts, your VMs will no longer have access to resources in the project. If you're not sure whether a service account is being used, Google recommendsdisabling the service accountbefore deleting it. Disabled service accounts can be re-enabled if they are still needed.

Example: Access Cloud Storage resources from your VM

After you have configured your VM to use a service account that has thestorage.admin role, you can use tools such as the gcloud CLI to manage files that you have stored on Cloud Storage. To access your Cloud Storage resources, complete the following:

  1. Ensure that the service account that is attached to your VM has theroles/storage.admin role.
  2. If your VM uses a custom OS image, install the gcloud CLI. By default, the gcloud CLI is installed on most public OS images that are provided by Google Cloud.
  3. Connect to the VM.
  4. From the VM, use theGoogle Cloud CLI to manage your Cloud Storage resources.

What's next?