Types of service accounts

Service accounts can be divided into the following categories:

• User-managed service accounts, which you create and manage yourself
• Service agents, which Google Cloud creates and manages

This page describes how each type of service account is created and used.

User-managed service accounts

User-managed service accounts are service accounts that you create in your projects. You can update, disable, enable, and delete these service accounts at your discretion. You can also manage other principals' access to these service accounts.

You can create user-managed service accounts in your project using the IAM API, the Google Cloud console, or the Google Cloud CLI.

By default, you can create up to 100 user-managed service accounts in a project. If this quota does not meet your needs, you can use the Google Cloud console to request a quota increase. Only user-created service accounts count towards this quota—default service accounts and service agents don't count towards the quota.

When you create a user-managed service account in your project, you choose a name for the service account. This name appears in the email address that identifies the service account, which uses the following format:

service-account-name@project-id.iam.gserviceaccount.com

To learn how to create a service account, see Create service accounts.

Default service accounts

Default service accounts are user-managed service accounts that are created automatically when you enable or use certain Google Cloud services. These service accounts let the service deploy jobs that access other Google Cloud resources. You are responsible for managing default service accounts after they are created.

If your application runs in a Google Cloud environment that has a default service account, your application can use the credentials for the default service account to call Google Cloud APIs. Alternatively, you can create your own user-managed service account and use it to authenticate. For details, see Set up Application Default Credentials.

Depending on your organization policy configuration, the default service account might automatically be granted the Editor role on your project. We strongly recommend that you disable the automatic role grant by enforcing the iam.automaticIamGrantsForDefaultServiceAccounts organization policy constraint. If you created your organization after May 3, 2024, this constraint is enforced by default.

If you disable the automatic role grant, you must decide which roles to grant to the default service accounts, and then grant these roles yourself.

If the default service account already has the Editor role, we recommend that you replace the Editor role with less permissive roles. To safely modify the service account's roles, use Policy Simulator to see the impact of the change, and then grant and revoke the appropriate roles.

The following table lists the services that create default service accounts:

Service agents

Some Google Cloud services need access to your resources so that they can act on your behalf. For example, when you use Cloud Run to run a container, the service needs access to any Pub/Sub topics that can trigger the container.

To meet this need, Google Cloud creates and manages service accounts for many Google Cloud services. These service accounts are known as service agents. You might see service agents in your project's allow policy, in audit logs, or on the IAM page in the Google Cloud console.

Service agents aren't created in your projects, so you won't see them when viewing your projects' service accounts. You can't access them directly.

By default, service agents aren't listed in the IAM page in the Google Cloud console, even if they've been granted a role on your project. To view role grants for service agents, select the Include Google-provided role grants checkbox.

Google Cloud has the following types of service agents:

• Service-specific service agents
• Google APIs Service Agent
• Role manager for service agents

Service-specific service agents

Most service agents are service-specific—they act on behalf of individual services. In many cases, these service agents are required for services to function properly. For example, service agents are what allow Cloud Logging sinks to write logs to Cloud Storage buckets.

Each service agent is associated with a resource. This resource is typically a project, folder, or organization, though it can also be a service-specific resource—for example, a Cloud SQL instance. This resource defines the scope of the service agent's actions. For example, if a service agent is associated with a project, it will act on behalf of a service for the project and its descendant resources.

You can determine which type of resource a service agent is associated with by looking at its email address:

• If the service agent is associated with a project, folder, or organization, its email address contains the numeric ID for that project, folder, or organization.
• If the service agent is associated with a service-specific resource, its email address contains a numeric project ID and a unique identifier. The numeric project ID indicates which project owns the resource that the service agent is associated with. The unique identifier distinguishes the service agent from other similar service agents in the same project.

Google APIs Service Agent

Your project's allow policy is likely to refer to a service account named the Google APIs Service Agent, with an email address that uses the following format: project-number@cloudservices.gserviceaccount.com.

This service account runs internal Google Cloud processes on your behalf. It is automatically granted the Editor role (roles/editor) on the project.

Role manager for service agents

Your audit logs for IAM might refer to the service account service-agent-manager@system.gserviceaccount.com.

This service account manages the roles that are granted to other service agents. It is visible only in audit logs.

For example, if you use a new API, Google Cloud might automatically create a new service agent and grant it roles on your project. Granting these roles generates an audit log entry, which shows that service-agent-manager@system.gserviceaccount.com set the allow policy for the project.

Service agent creation

The exact time that a service agent is created depends on what type of resource it's associated with.

Service agents that are associated with a service-specific resource are created when you create the resource. For more information on how to identify and configure these service agents, review the documentation for the associated resource.

Service agents that are associated with projects, folders, and organizations are created as you need them, usually when you first use a service. If necessary, you can also ask Google Cloud to create service agents for a service before you use the service. For more information, see Create and grant roles to service agents.

Service agent roles

Some actions in Google Cloud require service agents to create and access resources on your behalf. For example, when you create a Dataproc cluster, the Dataproc service agent needs permission to create Compute Engine instances in your project in order to create the cluster.

To get this access, service agents need specific IAM roles. Many project-level service agents are automatically granted the roles that they need. The names of these automatically granted roles typically end in serviceAgent or ServiceAgent. For other service agents, you need to grant them roles so that the service works correctly. To find out which service agents are granted roles automatically, see the service agent reference.

If you ask Google Cloud to create service agents before you use a service, you must grant the service agents the roles that they are typically granted automatically. This is because service agents that are created at a user's request aren't automatically granted roles. If you don't grant the service agents these roles, some services might not function properly. To learn how to grant these roles to service agents, see Create and grant roles to service agents.

Primary service agents

In the service agent reference, some service agents are identified as primary service agents. Primary service agents are service agents whose email address is returned when you trigger service agent creation for a service.

Audit logging

Sometimes, when a principal initiates an operation, a service agent executes an action on the principal's behalf. However, when you're reviewing audit logs for a service agent, it can be hard to tell who the service agent was acting on behalf of, and why.

The following service agents include these additional details in their audit logs:

• BigQuery Connection Service Agent
• BigQuery Connection Delegation Service Agent

These additional details are in the serviceDelegationHistory field of the audit log, which is nested in the authenticationInfo field. This field contains the following information:

• The original principal who created the job
• The service agent that executed the action
• The service that the service agent belongs to
• The job ID

For example, suppose example-user@example.com creates a job using the BigQuery Connection API. This job requires one of the BigQuery Connection API's service agents to execute an action. In this case, the audit log for the service agent's action would contain a serviceDelegationHistory field similar to the following:

{
  "protoPayload": {
    "@type": "type.googleapis.com/google.cloud.audit.AuditLog",
    "authenticationInfo": {
      "principalEmail": "bqcx-442188550395-jujw@gcp-sa-bigquery-condel.iam.gserviceaccount.com",
      "serviceDelegationHistory": {
        "originalPrincipal": "user:my-user@example.com",
        "serviceMetadata": [
          {
            "principalSubject": "serviceAccount:bqcx-442188550395-jujw@gcp-sa-bigquery-condel.iam.gserviceaccount.com",
            "serviceDomain": "bigquery.googleapis.com",
          }
        ]
      }
    }
  }
}

What's next

• Find out how to create and manage service accounts.
• Learn how to create and manage service account keys.
• Get best practices for working with service accounts.
• Review best practices for managing service account keys.