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AWS Snowball
Developer Guide

This guide is for the Snowball Edge. If you are looking for documentation for the Snowball, see the AWS Snowball User Guide.

Overview of Managing Access Permissions to Your Resources in the AWS Cloud

Every AWS resource is owned by an AWS account, and permissions to create or access a resource are governed by permissions policies. An account administrator can attach permissions policies to IAM identities (that is, users, groups, and roles), and some services (such as AWS Lambda) also support attaching permissions policies to resources.

Note

An account administrator (or administrator user) is a user with administrator privileges. For more information, see IAM Best Practices in the IAM User Guide.

When granting permissions, you decide who is getting the permissions, the resources they get permissions for, and the specific actions that you want to allow on those resources.

Resources and Operations

In AWS Snowball, the primary resource is a job. AWS Snowball also has devices like the Snowball and the AWS Snowball Edge device, however, you can only use those devices in the context of an existing job. Amazon S3 buckets and Lambda functions are resources of Amazon S3 and Lambda respectively.

As mentioned previously, jobs don't have Amazon Resource Names (ARNs) associated with them. However, other services' resources, like Amazon S3 buckets, do have unique (ARNs) associated with them as shown in the following table.

Resource Type ARN Format
File system arn:aws:s3:region:account-id:BucketName/ObjectName

AWS Snowball provides a set of operations to create and manage jobs. For a list of available operations, see the AWS Snowball API Reference.

Understanding Resource Ownership

The AWS account owns the resources that are created in the account, regardless of who created the resources. Specifically, the resource owner is the AWS account of the principal entity (that is, the root account, an IAM user, or an IAM role) that authenticates the resource creation request. The following examples illustrate how this works:

  • If you use the root account credentials of your AWS account to create a file system, your AWS account is the owner of the resource (in AWS Snowball, the resource is the job).

  • If you create an IAM user in your AWS account and grant permissions to create a job to that user, the user can create a job. However, your AWS account, to which the user belongs, owns the job resource.

  • If you create an IAM role in your AWS account with permissions to create a job, anyone who can assume the role can create a job. Your AWS account, to which the role belongs, owns the job resource.

Managing Access to Resources in the AWS Cloud

A permissions policy describes who has access to what. The following section explains the available options for creating permissions policies.

Note

This section discusses using IAM in the context of AWS Snowball. It doesn't provide detailed information about the IAM service. For complete IAM documentation, see What Is IAM? in the IAM User Guide. For information about IAM policy syntax and descriptions, see AWS IAM Policy Reference in the IAM User Guide.

Policies attached to an IAM identity are referred to as identity-based policies (IAM polices) and policies attached to a resource are referred to as resource-based policies. AWS Snowball supports only identity-based policies (IAM policies).

Identity-Based Policies (IAM Policies)

You can attach policies to IAM identities. For example, you can do the following:

  • Attach a permissions policy to a user or a group in your account – To grant a user permissions to create a job, you can attach a permissions policy to a user or group that the user belongs to.

  • Attach a permissions policy to a role (grant cross-account permissions) – You can attach an identity-based permissions policy to an IAM role to grant cross-account permissions. For example, the administrator in Account A can create a role to grant cross-account permissions to another AWS account (for example, Account B) or an AWS service as follows:

    1. Account A administrator creates an IAM role and attaches a permissions policy to the role that grants permissions on resources in Account A.

    2. Account A administrator attaches a trust policy to the role identifying Account B as the principal who can assume the role.

    3. Account B administrator can then delegate permissions to assume the role to any users in Account B. Doing this allows users in Account B to create or access resources in Account A. The principal in the trust policy can also be an AWS service principal if you want to grant an AWS service permissions to assume the role.

    For more information about using IAM to delegate permissions, see Access Management in the IAM User Guide.

The following is an example policy that allows a user to perform the CreateJob action for your AWS account.

{ "Version": "2012-10-17", "Statement": [ { "Sid": "", "Effect": "Allow", "Principal": { "Service": "importexport.amazonaws.com" }, "Action": "sts:AssumeRole", "Condition": { "StringEquals": { "sts:ExternalId": "AWSIE" } } } ] }

For more information about using identity-based policies with AWS Snowball, see Using Identity-Based Policies (IAM Policies) for AWS Snowball. For more information about users, groups, roles, and permissions, see Identities (Users, Groups, and Roles) in the IAM User Guide.

Resource-Based Policies

Other services, such as Amazon S3, also support resource-based permissions policies. For example, you can attach a policy to an S3 bucket to manage access permissions to that bucket. AWS Snowball doesn't support resource-based policies. 

Specifying Policy Elements: Actions, Effects, and Principals

For each job (see Resources and Operations), the service defines a set of API operations (see AWS Snowball API Reference) to create and manage said job. To grant permissions for these API operations, AWS Snowball defines a set of actions that you can specify in a policy. For example, for a job, the following actions are defined: CreateJob, CancelJob, and DescribeJob. Note that, performing an API operation can require permissions for more than one action.

The following are the most basic policy elements:

  • Resource – In a policy, you use an Amazon Resource Name (ARN) to identify the resource to which the policy applies. For more information, see Resources and Operations.

  • Action – You use action keywords to identify resource operations that you want to allow or deny. For example, depending on the specified Effect, snowball:* either allows or denies the user permissions to perform all operations.

  • Effect – You specify the effect when the user requests the specific action—this can be either allow or deny. If you don't explicitly grant access to (allow) a resource, access is implicitly denied. You can also explicitly deny access to a resource, which you might do to make sure that a user cannot access it, even if a different policy grants access.

  • Principal – In identity-based policies (IAM policies), the user that the policy is attached to is the implicit principal. For resource-based policies, you specify the user, account, service, or other entity that you want to receive permissions (applies to resource-based policies only). AWS Snowball doesn't support resource-based policies.

To learn more about IAM policy syntax and descriptions, see AWS IAM Policy Reference in the IAM User Guide.

For a table showing all of the AWS Snowball API actions, see AWS Snowball API Permissions: Actions, Resources, and Conditions Reference.

Specifying Conditions in a Policy

When you grant permissions, you can use the IAM policy language to specify the conditions when a policy should take effect. For example, you might want a policy to be applied only after a specific date. For more information about specifying conditions in a policy language, see Condition in the IAM User Guide.

To express conditions, you use predefined condition keys. There are no condition keys specific to AWS Snowball. However, there are AWS-wide condition keys that you can use as appropriate. For a complete list of AWS-wide keys, see Available Keys for Conditions in the IAM User Guide.