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Auto Scaling:Use a balanced distribution policy to deploy high-availability computing clusters

Last Updated:Oct 18, 2024

Auto Scaling can quickly provision a computing cluster that contains Elastic Compute Service (ECS) instances that are evenly distributed across multiple zones and monitor the status of the instances in real time to ensure high availability of the cluster. This topic describes how to use Auto Scaling to deploy a high-availability computing cluster that contains ECS instances that are evenly distributed across multiple zones and use preemptible instances to reduce resource costs.

Scenarios

Description

In scenarios such as distributed big data computing and AI training, a large amount of computing power is required during peak hours. In this case, you must quickly provision a high-availability computing cluster to address business demands.

For example, if you operate an online advertising company that utilizes machine learning to effectively deliver advertisements, your company requires substantial computing resources during times of high demand. When you create a computing cluster that contains multiple ECS instances, issues, such as creation failure due to lengthy manual processes and inadequate resources and temporary downtime of ECS instances due to failures in a zone, may occur. The preceding issues may pose risks to your business operations.

Solutions

You can use Auto Scaling to automatically create ECS instances and implement a balanced distribution policy to ensure that the instances are evenly distributed across multiple zones. You can also use preemptible instances to reduce resource costs.

image

Benefits

If you use Auto Scaling to deploy a high-availability computing cluster, you can obtain the following benefits:

  • Zero O&M costs

    You can use Auto Scaling to automatically change the number of ECS instances without the need for manual intervention.

  • High availability

    The balanced distribution policy of Auto Scaling ensures that ECS instances are evenly distributed across multiple zones, which prevents scaling failures due to insufficient resources in a zone. By default, the instance health check feature is enabled, which ensures that all ECS instances that belong to your scaling group are always available.

  • Ultra-high cost performance

    If you use preemptible instances as compute nodes, you can effectively reduce resource costs.

Procedure

Note
  • You must evaluate your business modules based on your business architecture and create a scaling group for the business modules that require a high-availability computing cluster.

  • You must prepare a custom image based on your application. Specify the custom image when you set up a scaling configuration to ensure that the ECS instances created based on the scaling configuration meet your business requirements. For more information, see Create a custom image from an instance.

  1. Log on to the Auto Scaling console.

  2. Create a scaling group.

    1. In the left-side navigation pane, click Scaling Groups.

    2. In the top navigation bar, select the region in which you activated Auto Scaling.

    3. In the upper-left corner of the Scaling Groups page, click Create.

    4. On the Create by Form tab, configure the scaling group and click Create.

      The following table describes the parameter settings used in this example. Use the default settings for parameters that are not included in the table. For information about how to create a scaling group, see Create scaling groups.

      均衡分布.png

      Parameter

      Example

      Description

      Scaling Group Name

      test

      Enter a name for the scaling group. The name must follow the format requirements displayed on the UI.

      Type

      ECS

      Select ECS, which specifies that the scaling group contains ECS instances.

      Instance Configuration Source

      Create from Scratch

      Do not specify a template used to automatically create ECS instances. After the scaling group is created, you can proceed to create a scaling configuration.

      Minimum Number of Instances

      100

      Specify the minimum instance limit. If the number of instances in the scaling group is smaller than the value of this parameter, Auto Scaling adds ECS instances to the scaling group until the number of ECS instances in the scaling group reaches the lower limit.

      Maximum Number of Instances

      120

      Specify the maximum instance limit. If the number of instances in the scaling group is greater than the value of this parameter, Auto Scaling removes ECS instances from the scaling group until the number of ECS instances in the scaling group does not exceed the upper limit.

      Show Advanced Settings > Scaling Policy

      Balanced Distribution Policy

      In this example, set this parameter to Balanced Distribution Policy. You must select multiple vSwitches to allow the policy to take effect.

      VPC

      vpc-2zeghwzptn5zii0w7****

      Select a VPC for the ECS instances in the scaling group.

      vSwitch

      vsw-2ze23nqzig8inprou****

      vsw-2zeet2ksvw7f14ryz****

      vsw-2ze94pjtfuj9vaymf****

      Select one or more vSwitches for the ECS instances in the scaling group.

      We recommend that you select multiple vSwitches. This way, the balanced distribution policy can ensure that ECS instances in the scaling group are evenly distributed across multiple zones, which improves the success rate of scale-out operations.

  3. Create a scaling configuration.

    1. On the Scaling Groups page, find the desired scaling group and click its ID.

    2. In the upper part of the scaling group details page, click the Instance Configuration Sources tab.

    3. On the Scaling Configurations tab, click Create Scaling Configuration.

    4. On the Create Scaling Configuration page, configure parameters to complete the process for creating a scaling configuration and click Create.

      The following table describes the parameter settings used in this example. Use the default settings for parameters that are not included in the table. For more information about how to create a scaling configuration, see Create a scaling configuration of the ECS type.

      Section

      Parameter

      Example

      Description

      Basic Information

      Scaling Configuration Name

      test

      Enter a name for the scaling configuration. The name must follow the format requirements displayed on the UI.

      Billing Method

      Preemptible Instance

      You can use Auto Scaling free of charge. However, you are charged for the ECS instances that are created during scale-out events. In this example, set the Billing Method parameter to Preemptible Instance. For more information, see Billing overview.

      Instance and Image

      Instance Configuration Mode

      Specify Instance Pattern

      Select Specify Instance Pattern to configure the specifications of ECS instances.

      Instance Attribute Combination

      2 vCPUs, 4 GiB of Memory, Enterprise Level

      Specify the number of vCPUs and the memory size of ECS instances based on your business requirements.

      Select Image

      test

      Select an image to deploy ECS instances.

      In actual business scenarios, we recommend that you select the custom image created based on your application.

      Storage

      System Disk

      Enterprise SSD (ESSD), 40 GiB, PL0

      Select a system disk for ECS instances. We recommend that you configure parameters in this section based on your business requirements.

      Network and Security Group

      Security Group

      sg-bp18kz60mefsicfg****

      Select an existing security group. For information about how to create a security group, see Create a security group.

      Management Settings

      Logon Credentials

      Set Later

      Select Set Later, which specifies that you must manually configure passwords for ECS instances after you create the ECS instances.

  4. Follow the on-screen instructions to enable the scaling group and scaling configuration.

Results

If you set the Minimum Number of Instances parameter to 100 when you create the scaling group, Auto Scaling evenly distributes 100 ECS instances across the specified zones to deliver a computing cluster and ensures the high availability of the cluster in the following aspects to reduce resource costs:

  • When issues occur as a result of insufficient resources in a single zone, Auto Scaling attempts to deploy ECS instances in alternative zones, thereby minimizing the impacts on your business application.

  • When preemptible instances are reclaimed, Auto Scaling creates new preemptible instances and replaces unhealthy ECS instances with new instances.

What to do next

If ECS instances are unevenly distributed across multiple zones due to insufficient resources, you can rebalance the distribution of the ECS instances across the zones. For more information, see Rebalance the distribution of ECS instances.