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

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.

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

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.

      

      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.