Different Alibaba Cloud accounts in the same organization or related organizations usually need to exchange events. You can use the cross-account event routing feature of EventBridge to route events from multiple Alibaba Cloud accounts to one Alibaba Cloud account for centralized processing. This topic describes the background information, limits, and procedure for routing events across Alibaba Cloud accounts. This topic also describes how to verify the result.
Background information
In an actual scenario shown in the following figure, Alibaba Cloud Account A and B belong to the same organization or related organizations. You can route the audit events of the RAM user of Alibaba Cloud Account A to the default event bus of Alibaba Cloud Account B for centralized processing. You can perform the following steps:
- Use Alibaba Cloud Account B that receives events to create a RAM role. Set the trusted entity of the RAM role to Alibaba Cloud Account A that sends events.
- Use Alibaba Cloud Account B to grant the RAM role the permissions to publish events. Alibaba Cloud Account A can assume the RAM role and has the permissions to publish events to Alibaba Cloud Account B.
- Use Alibaba Cloud Account B to modify the trust policy of the RAM role and attach the policy that is used to grant the permissions to publish events to the Alibaba Cloud services of Alibaba Cloud Account B. The Alibaba Cloud services of Alibaba Cloud Account B can also assume the RAM role and have the permissions to publish events to Alibaba Cloud Account B.
- Use Alibaba Cloud Account A to create an event rule and route audit events to the default event bus of Alibaba Cloud Account B.

Limits
- You can route events across Alibaba Cloud accounts only in the same region.
- Events of a default event bus can be routed only to a default event bus. Events of a custom event bus can be routed only to a custom event bus.
Step 1: Create a RAM role
- Use Alibaba Cloud Account B that receives events to log on to the Resource Access Management (RAM) console.
- In the left-side navigation pane, click RAM Roles.
- On the RAM Roles page, click Create RAM Role.
- In the Create RAM Role pane, set the Trusted Entity Type parameter to Alibaba Cloud Account, and then click Next.
- Configure the RAM role.
- Set the RAM Role Name parameter.
- Optional:Set the Note parameter.
- Select Other Alibaba Cloud Account as Select Trusted Alibaba Cloud Account, enter the ID of Alibaba Cloud Account A that sends events, and then click OK.
Step 2: Grant permissions to the RAM role
- Use Alibaba Cloud Account B that receives events to log on to the RAM console.
- In the left-side navigation pane, choose .
- On the Roles page, find the RAM role to which you want to grant permissions and click Add Permissions in the Actions column.
- In the Add Permissions panel, grant permissions to the RAM role.
Step 3: Modify the trust policy
Step 4: Create an event rule
- Log on to the EventBridge console by using Alibaba Cloud Account A.
- In the left-side navigation pane, click Event Buses.
- In the top navigation bar, select a region.
- On the Event Buses page, find the default event bus and click default.
- In the left-side navigation pane, click Event Rules.
- On the Event Rules page, click Create Rule.
- Complete the Create Rule wizard.
Verify the result
You can use Alibaba Cloud Account B to query events. For more information, see Query events by event ID.