Dataflow security and permissions

Dataflow pipelines can be run locally (to perform tests on small datasets), or on managed Google Cloud resources using the Dataflow managed service. Whether running locally or in the cloud, your pipeline and its workers use a permissions system to maintain secure access to pipeline files and resources. Dataflow permissions are assigned according to the role that's used to access pipeline resources. This document explains the following concepts:

• Upgrading Dataflow VMs.
• Roles and permissions required for running local and Google Cloud pipelines.
• Roles and permissions required for accessing pipeline resources across projects.
• Types of data used in a Dataflow service and in data security.

Before you begin

Read about Google Cloud project identifiers in the Platform Overview. These identifiers include the project name, project ID, and project number.

Upgrading and patching Dataflow VMs

Dataflow uses Container-Optimized OS. Hence, the security processes of Container-Optimized OS also apply to Dataflow.

Batch pipelines are time-bound and do not require maintenance. When a new batch pipeline starts, the latest Dataflow image is used.

For streaming pipelines, if a security patch is immediately required, Google Cloud notifies you by using security bulletins. For streaming pipelines, we recommend that you use the --update option to restart your job with the latest Dataflow image.

Dataflow container images are available in the Google Cloud Console.

Security and permissions for local pipelines

When you run locally, your Apache Beam pipeline runs as the Google Cloud account that you configured with the gcloud command-line tool executable. Hence, locally run Apache Beam SDK operations and your Google Cloud account have access to the same files and resources.

To list the Google Cloud account you selected as your default, run the gcloud config list command.

Note: Local pipelines can output data to local destinations, such as local files, or to cloud destinations, such as Cloud Storage or BigQuery. If your locally run pipeline writes files to cloud-based resources such as Cloud Storage, it uses your Google Cloud account credentials and the Google Cloud project that you configured as the gcloud command-line tool default. For instructions about how to authenticate with your Google Cloud account credentials, see the quickstart for the language you are using.

Security and permissions for pipelines on Google Cloud

When you run your pipeline, Dataflow uses two service accounts to manage security and permissions:

• The Dataflow service account. The Dataflow service uses the Dataflow service account as part of the job creation request (for example, to check project quota and to create worker instances on your behalf), and during job execution to manage the job.

• The worker service account. Worker instances use the worker service account to access input and output resources after you submit your job.

Dataflow service account

As part of running the Dataflow pipeline, the Dataflow service manipulates resources on your behalf (for example, creating additional VMs). When you run your pipeline on the Dataflow service, it uses the Dataflow service account (service-<project-number>@dataflow-service-producer-prod.iam.gserviceaccount.com). The Dataflow service account is created upon first usage of the resource Dataflow Job. This account gets assigned the Dataflow Service Agent role on the project, and has the necessary permissions to run a Dataflow job under the project, including starting Compute Engine workers. This account is used exclusively by the Dataflow service and is specific to your project.

You can review the Dataflow service account's permissions in the Cloud Console or the gcloud command-line tool.

Console

1. Go to the Roles page.

   Go to Roles

2. On the Cloud Console toolbar, select your project.

3. To view the Dataflow service account's permissions, select the Include Google-provided role grants checkbox at the top right, and select the Cloud Dataflow Service Agent checkbox.

gcloud

View the Dataflow service account's permissions:

gcloud iam roles describe roles/dataflow.serviceAgent

Since Google Cloud services expect to have read/write access to the project and its resources, it is recommended that you do not change the default permissions automatically established for your project. If you remove the permissions for the service account from the Identity and Access Management (IAM) policy, the accounts continue to be present as they are owned by the Dataflow service. If a Dataflow service account loses permissions to a project, Dataflow cannot launch VMs or perform other management tasks.

Best practice: Create a bucket owned by your project to use as the staging bucket for Dataflow. The default bucket permissions allow Dataflow to use the bucket to stage your pipeline's executable files.

Worker service account

Compute Engine instances execute Apache Beam SDK operations in the cloud. These workers use your project's worker service account to access your pipeline's files and other resources. The worker service account is used as the identity for all worker VMs. All requests that originate from the VM use the worker service account. This service account is also used to interact with resources such as Cloud Storage buckets and Pub/Sub topics.

For the worker service account to be able to create, run, and examine a job, ensure that it has the roles/dataflow.admin and roles/dataflow.worker roles. In addition, the iam.serviceAccounts.actAs permission is required for your user account in order to impersonate the service account.

Default worker service account

By default, workers use your project's Compute Engine default service account as the worker service account. This service account (<project-number>[e-mail]) is automatically created when you enable the Compute Engine API for your project from the API Library in the Cloud Console.

The Compute Engine default service account has broad access to your project's resources, which makes it easy to get started with Dataflow. However, for production workloads, we recommend that you create a new service account with only the roles and permissions that you need.

Note: In the past, Dataflow users were able to deploy applications that authenticated as the Compute Engine default service account, even if they didn't have permission to impersonate the Compute Engine default service account. This legacy behavior still affects some organizations. For more information, see Requiring impersonation permissions when attaching service accounts to resources.

Specifying a user-managed worker service account

If you want to create and use resources with fine-grained access control, you can create a user-managed service account and use it as the worker service account.

If you do not have a user-managed service account, you must create a service account and set your service account's required IAM roles. At a minimum, your service account must have the Dataflow Worker role. Your service account might also need additional roles to use Google Cloud resources as required by your job (such as, BigQuery, Pub/Sub, or writing to Cloud Storage). For example, if your job reads from BigQuery, your service account must also have at least the roles/bigquery.dataViewer role. Also, ensure that your user-managed service account has read and write access to the staging and temporary locations specified in the Dataflow job.

The user-managed service account can be in the same project as your job, or in a different project. If the service account and the job are in different projects, you must configure the service account before you run the job. You must also grant the Service Account Token Creator role to the following Google-managed service accounts on the user-managed service account:

• Compute Engine default service account (<project-number>[e-mail])
• Dataflow Service Agent (service-<project-number>@dataflow-service-producer-prod.iam.gserviceaccount.com)

Java

Use the --serviceAccount option and specify your service account when you run your pipeline job: --serviceAccount=my-service-account-name@<project-id>.iam.gserviceaccount.com

Python

Use the --service_account_email option and specify your service account when you run your pipeline job: --service_account_email=my-service-account-name@<project-id>.iam.gserviceaccount.com

You can obtain a list of your project's service accounts from the Permissions page in the Cloud Console.

Accessing Google Cloud resources across multiple Google Cloud projects

Your Apache Beam pipelines can access Google Cloud resources in other Google Cloud projects. These resources include:

• Cloud Storage buckets
• BigQuery datasets
• Pub/Sub topics and subscriptions
• Firestore datasets

To ensure that your Apache Beam pipeline can access these resources across projects, you need to use the resources' respective access control mechanisms to explicitly grant access to your Dataflow project's worker service account.

Accessing Cloud Storage buckets across Google Cloud projects

To give your Dataflow project access to a Cloud Storage bucket that a different Google Cloud project owns, make the bucket accessible to your Dataflow project's worker service account. You can use Cloud Storage Access Controls to grant the required access.

Note: Ensure that your worker service account permissions are consistent with your IAM settings. Due to the inconsistency between IAM and ACL policies, the Cloud Storage bucket might become inaccessible to your Dataflow jobs when the Cloud Storage bucket is migrated from fine-grained access to uniform bucket-level access. For more information, see Common error guidance.

To obtain a list of your Dataflow project's service accounts, check the IAM & Admin page in the Cloud Console. Once you have the account names, you can run gsutil commands to grant the project's service accounts ownership (read/write permission) to both the bucket and its contents.

To grant your Dataflow project's service accounts access to a Cloud Storage bucket in another project, use the following command in your shell or terminal window: gsutil acl ch -u <project-number>[e-mail]:OWNER gs://<bucket>

To grant your Dataflow project's service accounts access to the existing contents of a Cloud Storage bucket in another project, use the following command in your shell or terminal window: gsutil -m acl ch -r -u <project-number>[e-mail]:OWNER gs://<bucket>

Note: The -m option runs the command in parallel for quicker processing; the -r option runs the command recursively on resources within the bucket.

The prior command grants access only to existing resources. Granting the Dataflow project's service accounts default permission to the bucket allows it to access future resources added to the bucket: gsutil defacl ch -u <project-number>[e-mail]:OWNER gs://<bucket>

Tip: You can also set bucket permissions from the Cloud Console. See Setting Bucket Permissions for more information.

Accessing BigQuery datasets across Google Cloud projects

You can use the BigQueryIO API to access BigQuery datasets owned by a different Google Cloud project (that is, not the project with which you're using Dataflow). For the BigQuery source and sink to operate properly, the following two accounts must have access to any BigQuery datasets that your Dataflow job reads from or writes to:

• The Google Cloud account that you use to run the Dataflow job.
• The worker service account that runs the Dataflow job.

You might need to configure BigQuery to explicitly grant access to these accounts. See BigQuery Access Control for more information on granting access to BigQuery datasets using either the BigQuery page or the BigQuery API.

Among the required BigQuery permissions, the bigquery.datasets.get IAM permission is required by the pipeline to access a BigQuery dataset. Typically, most BigQuery IAM roles include the bigquery.datasets.get permission, but the roles/bigquery.jobUser role is an exception.

For example, if your Google Cloud account is [e-mail] and the project number of the project where you execute the Dataflow job is 123456789, the following accounts must all be granted access to the BigQuery Datasets used: [e-mail], and [e-mail].

Accessing Pub/Sub topics and subscriptions across Google Cloud projects

To access a Pub/Sub topic or subscription owned by a different Google Cloud project, use Pub/Sub's Identity and Access Management features to set up cross-project permissions. Dataflow uses the worker service account to run your jobs and grant this service account access to the Pub/Sub resources in the other project.

Permissions from the following Pub/Sub roles are required:

• roles/pubsub.subscriber: to consume data and create subscriptions
• roles/pubsub.viewer: to query the configuration of topics and subscriptions. In order to extend the deadlines appropriately, Dataflow needs access to the acknowledgment deadlines for subscriptions. Also, this permission allows Dataflow to check for unsupported settings on subscriptions and topics that might cause problems.

See Sample use case: cross-project communication for more information and some code examples that demonstrate how to use Pub/Sub's Identity and Access Management features.

Accessing Firestore across Google Cloud projects

To access a Firestore database (in Native mode or Datastore mode) owned by a different Google Cloud project, add your Dataflow project's Compute Engine (<project-number>[e-mail]) service account as editor of the project that owns the Firestore. Also, enable the Firestore API in both projects from the API Library in the Google Cloud Console.

Accessing images for projects with a trusted image policy

If you have a trusted image policy set up for your project and your boot image is located in another project, ensure that the trusted image policy is configured to have access to the image. For example, if you are running a templated Dataflow job, ensure that the policy file includes access to the dataflow-service-producer-prod project. This is a Cloud project that contains the images for template jobs.

Data access and security

The Dataflow service works with two kinds of data:

• End-user data. This is the data that is processed by a Dataflow pipeline. A typical pipeline reads data from one or more sources, implements transformations of the data, and writes the results to one or more sinks. All the sources and sinks are storage services that are not directly managed by Dataflow.

• Operational data. This data includes all the metadata that is required for managing a Dataflow pipeline. This data includes both user-provided metadata such as a job name or pipeline options and also system-generated metadata such as a job ID.

The Dataflow service uses several security mechanisms to keep your data secure and private. These mechanisms apply to the following scenarios:

• Submitting a pipeline to the service
• Evaluating a pipeline
• Requesting access to telemetry and metrics during and after a pipeline execution
• Using a Dataflow service such as Shuffle or Streaming Engine

Data locality

Note: We recommend that you always specify a region when you run a pipeline. Support for default regions would be discontinued in a future release.

All the core data processing for the Dataflow service happens in the region that is specified in the pipeline code. If a region is not specified, the default region us-central1 is used. A pipeline job can optionally read and write from sources and sinks in other regions if you specify that option in the pipeline code. However, the actual data processing occurs only in the region that is specified to run the Dataflow VMs.

Pipeline logic is evaluated on individual worker VM instances. You can specify the zone in which these instances and the private network over which they communicate are located. Ancillary computations for the platform depend on metadata such as Cloud Storage locations or file sizes.

Dataflow is a regional service. For more information about data locality and regional endpoints, see Regional endpoints.

Data in a pipeline submission

The IAM permissions for your Google Cloud project control access to the Dataflow service. Any principals who are given editor or owner rights to your project can submit pipelines to the service. To submit pipelines, you must authenticate using the gcloud command-line tool. After you are authenticated, your pipelines are submitted using the HTTPS protocol. For instructions about how to authenticate with your Google Cloud account credentials, see the quickstart for the language that you are using.

Data in a pipeline evaluation

As part of evaluating a pipeline, temporary data might be generated and stored locally in the worker VM instances or in Cloud Storage. Temporary data is encrypted at rest and does not persist after a pipeline evaluation concludes. Such data can also be stored in the Shuffle service or Streaming Engine service (if you have opted for the service) in the same region as specified in the Dataflow pipeline.

Java

By default, Compute Engine VMs are deleted when the Dataflow job completes, regardless of whether the job succeeds or fails. This means that the associated Persistent Disk, and any intermediate data that might be stored on it, is deleted. The intermediate data stored in Cloud Storage can be found in sublocations of the Cloud Storage path that you provide as your --stagingLocation and/or --tempLocation. If you are writing output to a Cloud Storage file, temporary files might be created in the output location before the Write operation is finalized.

Python

By default, Compute Engine VMs are deleted when the Dataflow job completes, regardless of whether the job succeeds or fails. This means that the associated Persistent Disk, and any intermediate data that might be stored on it, is deleted. The intermediate data stored in Cloud Storage can be found in sublocations of the Cloud Storage path that you provide as your --staging_location and/or --temp_location. If you are writing output to a Cloud Storage file, temporary files might be created in the output location before the Write operation is finalized.

Data in pipeline logs and telemetry

Information stored in Cloud Logging is primarily generated by the code in your Dataflow program. The Dataflow service might also generate warning and error data in Cloud Logging, but this is the only intermediate data that the service adds to logs. Cloud Logging is a global service.

Telemetry data and associated metrics are encrypted at rest, and access to this data is controlled by your Google Cloud project's read permissions.

Data in Dataflow services

If you use Dataflow Shuffle or Dataflow Streaming for your pipeline, do not specify the zone pipeline options. Instead, specify the region and set the value to one of the regions where Shuffle or Streaming is currently available. Dataflow auto-selects the zone in the region you specified. The end-user data in transit stays within the worker VMs and in the same zone. These Dataflow jobs can still read and write to sources and sinks that are outside the VM zone. The data in transit can also be sent to Dataflow Shuffle or Dataflow Streaming services, however the data always remains in the region specified in the pipeline code.

Recommended practice

We recommend that you use the security mechanisms available in your pipeline's underlying cloud resources. These mechanisms include the data security capabilities of data sources and sinks such as BigQuery and Cloud Storage. It's also best not to mix different trust levels in a single project.