To ensure the data security of your resources, you can use Resource Access Management (RAM) policies to enable access control for your resources. This topic describes the RAM policies of NAT Gateway.
Overview
RAM uses permission control to regulate access from RAM users, RAM user groups, and RAM roles to a resource. A policy is a set of permissions. You can attach policies to RAM users, RAM user groups, or RAM roles to grant them permissions on a resource.
Permissions
Alibaba Cloud accounts, RAM users, and resource creators have different default permissions.
- An Alibaba Cloud account is the resource owner and controls all permissions.
- Each Alibaba Cloud resource has only one owner. The owner must be an Alibaba Cloud account and has complete control over the resource.
- The resource owner is not necessarily the resource creator. For example, if a RAM user has permissions to create Alibaba Cloud resources, the resources created by this RAM user belong to the Alibaba Cloud account of the RAM user. The RAM user is the resource creator, but is not the resource owner.
- A RAM user has no permissions by default.
- A RAM user is an identity that is used to manage resources. Before a RAM user can perform operations, the RAM user must be granted the required permissions by the Alibaba Cloud account. The required permissions must be granted by attaching one or more explicit allow policies.
- A new RAM user can manage resources only after the RAM user is granted the required permissions.
- As a resource creator, a RAM user is not automatically granted the permissions on the created resources.
- A RAM user can create resources after the RAM user is granted the required permissions.
- To grant the RAM user the required permissions, the resource owner must attach one or more explicit allow policies to the RAM user.
Policy
A policy defines a set of permissions that are described based on the policy structure and syntax. You can use policies to describe the authorized resource sets, authorized operation sets, and authorization conditions.
RAM supports the following two types of policy:
System policy: System policies are created and updated by Alibaba Cloud. You can use these policies but you cannot modify them. For more information, see System policies for NAT gateways.
Custom policy: If system policies cannot meet your business requirements, you can create custom policies to implement fine-grained permission management. For more information, see Custom policies for NAT gateways.
Attach policies to a principal
After you create a policy, you can attach it to a RAM user, a RAM user group, or a RAM role to grant the permissions defined in the policy to the principal.
You can attach one or more policies to a RAM user, a RAM user group, or a RAM role.
The attached policies can be system policies or custom policies.
If the attached policies are modified, the modifications automatically take effect. You do not need to attach the modified policies to RAM principals again.