Alibaba Cloud uses permissions to describe the ability of internal identities (such as users, user groups, roles) to access specific resources. Permission refers to allowing or denying to perform certain operations on certain resources under certain conditions. An authorization policy is a collection of access permissions.
This document describes the relationships between Alibaba Cloud permissions and authorization policies, to help you understand and use them correctly.
The primary account (resource owner) controls all permissions.
- Each resource has one and only one owner (resource owner). The owner must be an Alibaba Cloud account. This account pays for and has full control over the resource.
- The resource owner is not necessarily the resource creator. For example, a RAM user is granted permission to create a resource. The resource belongs to the primary account. This user is the resource creator but not the resource owner.
A RAM user (operator) does not have any permissions by default.
- A RAM user represents an operator and must be explicitly authorized to perform any operation.
- A new RAM user has no operation permission by default, and cannot operate on resources in the console or by using APIs until the authorization is granted.
Resource creators (RAM users) are not automatically granted permissions for the resources they have created.
- If a RAM user is granted permission to create a resource, the user will be allowed to create the resource.
- However, the RAM user does not automatically have any permissions for the created resource, unless the resource owner has an explicit authorization on him.
An authorization policy is a set of permissions described by Policy syntax structure that accurately describes the set of authorized resources, the set of operations, and the authorization conditions. The deny first principle is followed when there are both allow and deny authorization statements in an authorization policy.
In RAM, an authorization policy is a type of resource entity. Users can create, update, delete, and view authorization policies. RAM supports the following two authorization policies:
- System authorization policies are a group of general permissions created and managed by Alibaba Cloud, such as read-only permission for ECS or full permissions for ECS. You can use these policies, but cannot modify them.
- Custom authorization policies are a group of permissions created and managed by users. They can be used to expand and supplement system authorization policies.
System authorization policies describe coarse-grained permissions. If you require finer-grained authorization policies, such as policies that precisely control permissions for a certain ECS instance or that have additional authorization conditions, you must create custom authorization policies.
Authorization to a RAM user
Authorization to a RAM user refers to binding one or more authorization policies to a user, user group, or role.
- The bound authorization policy can be either a system authorization policy or a custom authorization policy.
- If a bound authorization policy is updated, the updated policy automatically takes effect, and you do not have to rebind it.