This topic provides answers to some commonly asked questions about the features of ApsaraMQ for MQTT.
Does an ApsaraMQ for MQTT instance support restart?
An ApsaraMQ for MQTT instance does not support restart.
What is the difference between the cloud SDK and the client SDK?
The cloud SDK uses the AMQP protocol and supports clustering consumption. The client SDK uses the open source MQTT protocol and supports broadcasting consumption.
Why does a Connector task created from MQTT show an abnormal status?
You can check the creation date of your ApsaraMQ for MQTT instance. Older instances do not support the Connector feature, which causes the task status to appear abnormal. To use Connector, create a new ApsaraMQ for MQTT instance.
What is the maximum retention period for offline messages?
Three days.
ApsaraMQ for MQTT retains offline messages only if the QoS parameter is set to 1 and the cleanSession parameter is set to false. These messages can be retained for up to three days and are automatically deleted after this period.
Platinum edition instances support customization. To request customization, contact ApsaraMQ for MQTT technical support in the DingTalk group with ID 116015007918.
When are offline message notifications sent?
The broker starts pushing offline messages after it detects that the client is online.
What is a suitable keepalive time?
We recommend setting the keepalive time to the default value in ApsaraMQ for MQTT: 90 seconds.
Does ApsaraMQ for MQTT support will and retained messages?
This feature is not supported.
Are topics automatically deleted if they are not used for a long period of time?
No, it will not.
ApsaraMQ for MQTT does not automatically delete created topics and group IDs unless your instance is released upon expiration.
Can an endpoint be configured as an IP address?
Not supported.
You must use a domain name to access the ApsaraMQ for MQTT broker. Do not connect directly using the IP address to which the domain name resolves. The IP address is subject to change and may cause connection failures.
Does ApsaraMQ for MQTT support the clustering consumption mode?
The clustering consumption mode is supported by the cloud SDK but not the client SDK. You can use the client SDK to send messages and use the cloud SDK to subscribe to messages.
The cloud SDK is suitable for scenarios that require cloud application integration. For more information, see Overview of cloud-side development.
Does ApsaraMQ for MQTT support the configuration of other alert recipients?
Monitoring alerts are sent by default to the mobile number bound to your Alibaba Cloud account. You cannot change this number to the mobile number of another recipient.
Does ApsaraMQ for MQTT support the migration of instances across Alibaba Cloud accounts?
This feature is not supported.