A group ID specifies the name of a group of nodes (devices) with identical logic and features. Before you send and receive messages, you must create a group. This topic describes how to create and delete a group and how to query the details of a group in the ApsaraMQ for MQTT console.
Usage notes
Group IDs must be unique within an instance, but can be the same in different instances.
A group ID must start with "GID_" or "GID-" and must be 7 to 64 characters in length. It can contain only letters, digits, hyphens (-), and underscores (_).
Create a group
Log on to the ApsaraMQ for MQTT console. In the left-side navigation pane, click Instances.
In the top navigation bar, select the region where the instance that you want to manage resides. On the Instances page, click the instance name to go to the Instance Details page.
In the left-side navigation pane, click Groups. In the upper-left corner of the Groups page, click Create Group.
In the Create Group panel, set the Group ID parameter and click OK.
Delete a group
After you delete a group, disconnected producer and consumer clients that are identified by the group ID fail the authentication when they attempt to reconnect to ApsaraMQ for MQTT. The deletion operation does not affect producer or consumer clients that are connected to ApsaraMQ for MQTT.
Go to the Groups page.
In the group list, find the group that you want to delete. In the Actions column, choose .
On the dialog box that appears, click OK.
Query the details of a group
- Go to the Groups page.
- Find the instance for which you want to query group details in the instance list. In the Actions column, choose .
- In the group list, find the group that you want to query. Click the group ID to go to the Group Details page.
References
After you create a topic and a group, you can send and receive messages. For more information, see Use ApsaraMQ for MQTT SDK for Java to implement messaging between ApsaraMQ for MQTT clients and backend service applications.