ApsaraMQ for Kafka:Elasticity policies

Elasticity

Serverless ApsaraMQ for Kafka Standard Edition and Professional Edition instances provide the elasticity capability to meet different traffic needs in the production environment. You can change the reserved capacity for message production and consumption for your ApsaraMQ for Kafka instance based on your business requirements.

Scheduled elasticity policies

Change object

• A scheduled elasticity policy is used to change the reserved capacity for message production or consumption. If the peak short-term traffic exceeds the maximum elastic traffic allowed, we recommend that you configure a scheduled elasticity policy to change the reserved capacity for message production or consumption to respond to requests that have ultra-large amounts of traffic within seconds.

• You can configure scheduled policies for Standard Edition and Professional Edition instances. For information about elastic traffic thresholds, see Elasticity.

Change impact

• During the configuration upgrade or downgrade of an instance, clients temporarily disconnect from brokers and then reconnect to the brokers for load balancing due to the increase or decrease in the number of brokers in the cluster. This may cause a few errors. We recommend that you configure the retry mechanism on the clients to resend messages that failed to be sent during the configuration upgrade or downgrade.

• The configuration upgrade or downgrade does not affect the overall service.

Effective period

• To ensure the successful upgrade or downgrade of the reserved capacity to the preset capacity during the effective period, the broker runs a configuration upgrade or downgrade task before the effective period. We recommend that you configure scheduled elasticity tasks in advance to provide sufficient time for the execution of configuration upgrade or downgrade tasks.

• The broker executes the configuration downgrade task after the effective period ends.

• To prevent the broker from repeatedly executing configuration upgrade and downgrade tasks during the effective period, make sure that the interval between two consecutive scheduled elasticity tasks is greater than 60 minutes.

• If the estimated execution time is earlier than the current point in time, a task that does not require repeated execution is not executed and a task that requires repeated execution is executed in the next execution cycle.

• You can upgrade an instance to a reserved capacity that is higher than the reserved capacity specified in the enabled scheduled elasticity policy. After the upgrade is complete, all scheduled elasticity policies with a reserved capacity lower than the upgraded reserved capacity are disabled.

Add a scheduled elasticity policy

1. Log on to the ApsaraMQ for Kafka console. In the Resource Distribution section of the Overview page, select the region where the ApsaraMQ for Kafka instance that you want to manage resides.

2. On the Instances page, click the name of the instance that you want to manage.

3. On the Instance Details page, click the Elasticity Policy tab.

4. In the Scheduled Elasticity Policy section, click Create Scheduled Elasticity Policy. In the Create Scheduled Elasticity Policy panel, configure the following parameters and click OK.

   • Policy Name: Enter a policy name.

   • Reserved Capacity for Message Production: Specify the reserved capacity for message production during the scheduled period of time.

   • Reserved Capacity for Message Consumption: Specify the reserved capacity for message consumption during the scheduled period of time.

   • Repeated Execution Rule

     • Exactly-once Execution: The elasticity task is executed only once. If you select this value, specify the period of time during which the elasticity task is executed in the yyyy-MM-dd HH:mm format. The start time must range from 1 hour to 7 days from the current point in time. The interval between the start time and end time of the elasticity task must range from 30 minutes to 7 days.

     • Every Day: The elasticity task is executed every day. If you select this value, specify the time during which the elasticity task is executed in the HH:mm format. The interval between the start time and end time of the elasticity task must range from 30 minutes to 12 hours.

     • Every Week: The elasticity task is executed during a specific period of time on specific days of each week. If you select this value, select the days on which the elasticity task is executed and specify the period of time during which the elasticity task is executed in the HH:mm format. The interval between the start time and end time of the elasticity task must range from 30 minutes to 12 hours.

   • Effective Period: Specify the start time and end time of the elasticity task based on the repeated execution rule.

     Important

     To ensure the successful upgrade or downgrade of the reserved capacity to the preset capacity during the effective period, the interval between two consecutive scheduled elasticity tasks must be greater than 60 minutes.

   • Effective or Not: specifies whether the policy takes effect immediately.

   After you create a scheduled elasticity policy, you can view the details of the policy in the Elasticity Policy tab of the Instance Details page. The details include the reserved capacity for message production, reserved capacity for message consumption, effective period, and estimated upgrade time.

Start a scheduled elasticity policy

1. In the Scheduled Elasticity Policy section, find the scheduled elasticity policy that you want to manage.

2. In the Effective or Not column, turn on the button.

   After the scheduled elasticity task takes effect, you can view the reserved capacities for message production and consumption in a future period (1 day, 2 days, 3 days, or 7 days) in the Policy Preview section.

Stop or delete a scheduled elasticity policy

In the Scheduled Elasticity Policy section, find the scheduled elasticity policy that you want to manage.