Modifying RabbitMQ Instance Specifications

After creating a RabbitMQ instance, you can increase or decrease its specifications. For details, see Table 1.

**Table 1** Supported specification changes (for RabbitMQ 3.x.x)
Instance Type	Modified Object	Increase	Decrease
Cluster	Brokers	√	×
	Storage space	√	×
	Broker flavor	√	√
Single-node	Brokers	×	×
	Storage space	√	×
	Broker flavor	√	√

Impact

**Table 2** Impact of specification modification
Modified Object	Impact
Brokers	During the broker increase, the RabbitMQ workload balance process is restarted, triggering a master/standby switchover and causing services to temporarily stutter. Ensure that your client can auto-reconnect. Modify specifications during off-peak hours. The change duration depends on the number of added brokers, and is 5–10 minutes per broker. The total change duration = Single change duration × Number of added brokers.
Storage space	Storage space expansion does not affect services. You can expand the storage space 20 times for each instance. Available storage space = Actual storage space – Storage space for storing logs – Disk formatting loss For example, if the storage space is expanded to 700 GB, the storage space for storing logs is 100 GB, and the disk formatting loss is 7 GB, then the available storage space after capacity expansion will be 593 GB. The total change duration is within 5 minutes.
Broker flavor	For single-node RabbitMQ 3.x.x instances, nodes are restarted and services may temporarily stutter in minutes during the modification. Ensure that your client can auto-reconnect. Modify specifications during off-peak hours. For cluster RabbitMQ 3.x.x instances not configured with mirrored/quorum queues, nodes are restarted in sequence and services may stutter in minutes during the modification. Ensure that your client can auto-reconnect. Modify specifications during off-peak hours. For cluster RabbitMQ 3.x.x instances not configured with mirrored/quorum queues, nodes are restarted in sequence and services may stutter for several seconds during the modification. Ensure that your client can auto-reconnect. Modify specifications during off-peak hours. During the modification of cluster RabbitMQ 3.x.x instances, connections to the changed nodes will be switched to other nodes, posing overload risks (for example, connections excess or memory high watermark) on them. You are advised to use them within the instance specifications. For more information, see Specifications. Persistent exchanges, queues, and messages are required. Otherwise, messages may be lost after node restarts. For details, see Configuring RabbitMQ Persistence. Brokers will be restarted in sequence during an instance change, which depends on the number of brokers. The change duration per single broker is 5–10 minutes. The total change duration = Single change duration × Number of brokers.

The following example shows how to configure message retry on a Java client.

ConnectionFactory connectionFactory = new ConnectionFactory();
//Set a service address.
connectionFactory.setHost("localhost");
//Set a port.
connectionFactory.setPort(5672);
//Auto retry:
connectionFactory.setAutomaticRecoveryEnabled(true);
connectionFactory.setNetworkRecoveryInterval(5);
connectionFactory.setTopologyRecoveryEnabled(true);

Notes and Constraints

To ensure that the instance runs properly, do not perform other operations on the instance during the modification.
The price may change after the modification.

Prerequisites

A RabbitMQ instance has been created and is in the Running state.

Increasing the Storage Space (for 3.x.x)

Log in to the console.
In the upper left corner, click and select a region.
Click in the upper left corner and choose Application > Distributed Message Service for RabbitMQ to open the RabbitMQ instance list.
Modify the instance specifications using either of the following methods:
- In the row containing the desired instance, click Modify Specifications.
- Click the desired RabbitMQ instance to view its details. In the upper right corner, click Modify Specifications.
Specify the required storage space.
1. For Change By, select Storage. For Storage Space per Broker, specify a new storage space. The storage space varies by instance specifications. For details, see Specifications. Click Next.
2. Confirm the configurations and click Submit.
3. Return to the instance list and check whether the change succeeded.
  - If the instance status has changed from Changing to Running, the change succeeded. View the new storage space (Storage space per broker × Number of brokers) in the Used/Available Storage Space (GB) column in the instance list.
  - If the instance status has changed from Changing to Change failed, the change failed. Move the cursor over Change failed to check the failure cause.
    Instances in the Change failed state cannot be modified, or deleted. After the instance status automatically changes from Change failed to Running, you can continue to perform operations. If the status does not change to Running, contact customer service.

Increasing the Broker Quantity (V3.x.x)

Log in to the console.
In the upper left corner, click and select a region.
Click in the upper left corner and choose Application > Distributed Message Service for RabbitMQ to open the RabbitMQ instance list.
Modify the instance specifications using either of the following methods:
- In the row containing the desired instance, click Modify Specifications.
- Click the desired RabbitMQ instance to view its details. In the upper right corner, click Modify Specifications.
Specify the required number of brokers.
1. For Modify By, select Brokers. Then, enter the number of brokers. The broker quantity range varies by instance specifications. For details, see Specifications. If public access has been enabled, configure EIPs for the new brokers. Then click Next.
2. Confirm the configurations and click Submit.
3. Return to the instance list and check whether the change succeeded.
  - If the instance status has changed from Changing to Running, the change succeeded. You can check the new broker quantity in the Flavor column.
  - If the instance status has changed from Changing to Change failed, the change failed. Move the cursor over Change failed to check the failure cause.
    Instances in the Change failed state cannot be modified, or deleted. After the instance status automatically changes from Change failed to Running, you can continue to perform operations. If the status does not change to Running, contact customer service.

Increasing/Decreasing a Broker Flavor (V3.x.x)

Log in to the console.
In the upper left corner, click and select a region.
Click in the upper left corner and choose Application > Distributed Message Service for RabbitMQ to open the RabbitMQ instance list.
Modify the instance specifications in either of the following ways:
- In the row containing the desired instance, click Modify Specifications.
- Click the desired RabbitMQ instance to view its details. In the upper right corner, click Modify Specifications.
Specify the required broker flavor.
1. For Modify By, select Broker Flavor. Then, select a new flavor and click Next.
2. Confirm the configurations and click Submit.
3. Return to the instance list and check whether the change succeeded.
  - If the instance status has changed from Changing to Running, the change succeeded. You can check the new broker flavor in the Flavor column.
  - If the instance status has changed from Changing to Change failed, the change failed. Move the cursor over Change failed to check the failure cause.
    Instances in the Change failed state cannot be modified, or deleted. After the instance status automatically changes from Change failed to Running, you can continue to perform operations. If the status does not change to Running, contact customer service.