What is a system 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. Alibaba Cloud Resource Access Management (RAM) provides system policies and custom policies. All system policies are created and updated by Alibaba Cloud. You can use system policies, but you cannot modify them. You can manage and update custom policies based on your business requirements. You can create, update, and delete custom policies. During service iteration, CEN adds new permissions to system policies to support new features and capabilities. The update of a system policy affects all RAM identities to which the policy is attached, including RAM users, RAM user groups, and RAM roles. For more information about RAM policies, see Policy overview.
System policies are designed for new users to quickly get started with Alibaba Cloud products on the management console, though they also enable the use of more advanced methods like API operations or CLI commands. If you are familiar with the advanced methods, we recommend that you use custom policies to implement finer-grained control on who is permitted to call what API operations, thereby improving security.
System policies can be classified into service system policies, service role policies, and service-linked role policies. Some cloud services provide only one or two of the three types of policies. For more information, see the policy types that are described in the following section.
Service system policies
AliyunCENFullAccess
The AliyunCENFullAccess policy: Provides full access to CEN via Management Console. It can be attached to RAM identities.
AliyunCENReadOnlyAccess
The AliyunCENReadOnlyAccess policy: Provides read-only access to CEN via Management Console. It can be attached to RAM identities.
Service-linked role policies
AliyunServiceRolePolicyForCEN
CEN assumes the AliyunServiceRolePolicyForCEN service-linked role to access the resources in other cloud services. The AliyunServiceRolePolicyForCEN policy is the dedicated authorization policy of the AliyunServiceRoleForCEN service-linked role. This policy is defined and used by CEN. You cannot modify or delete the policy. Do not attach this policy to a RAM identity other than the service-linked role.
AliyunServiceRolePolicyForTRFlowLog
CEN assumes the AliyunServiceRolePolicyForTRFlowLog service-linked role to access the resources in other cloud services. The AliyunServiceRolePolicyForTRFlowLog policy is the dedicated authorization policy of the AliyunServiceRoleForTRFlowLog service-linked role. This policy is defined and used by CEN. You cannot modify or delete the policy. Do not attach this policy to a RAM identity other than the service-linked role.
References
By default, RAM identities do not have any permissions. RAM identities can access cloud resources within an Alibaba Cloud account only after an account administrator grants the required permissions to the RAM identities. To ensure resource security, we recommend that you grant only the required permissions to the RAM identities based on the principle of least privilege. For more information, see the following topics: