Auto Scaling:Automatically unbind secondary ENIs from ECS instances

Procedure

Step 1: Grant OOS permissions to the RAM role

You must have the permissions to execute OOS templates. In this example, the ACS-ESS-LifeCycleDetachNetworkInterfaceAndDeleteEip public template is used. The template defines the ECS, Auto Scaling, and EIP resources that are required to perform O&M operations.

1. Log on to the RAM console.

2. In the left-side navigation pane, choose Identities > .

3. Find the RAM role OOSServiceRole and click Add Permissions in the Actions column.

   Grant the required permissions to OOSServiceRole.

4. In the Add Permissions panel, configure parameters as prompted and click OK.

   The following table describes the parameters that are used in this example. For parameters that are not described in the table, use the default settings.

   Parameter	Description
   Authorized Scope	Select Alibaba Cloud Account.
   Select Policy	Select the following system policies: AliyunECSFullAccess, AliyunESSFullAccess, and AliyunEIPFullAccess.

Step 2: Create a lifecycle hook and trigger a scale-in

1. Log on to the Auto Scaling console.

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

3. In the top navigation bar, select the region where Auto Scaling is activated.

4. Find a scaling group and use one of the following methods to go to the scaling group details page:

   • Click the ID of the scaling group in the Scaling Group Name/ID column.

   • Click Details in the Actions column.

5. Create a lifecycle hook.

   1. In the upper part of the scaling group details page, click the Lifecycle Hook tab.

   2. Click Create Lifecycle Hook.

   3. Configure parameters of the lifecycle hook and click OK.

      The following table describes the parameters that are used in this example. For parameters that are not described in the table, use the default settings.

      Parameter	Description
      Name	Enter ESSHookForDeleteNicAndEip.
      Scaling Activity	Select Scale-in Event.
      Timeout Period	Configure the Timeout Period parameter based on your business requirements. Unit: seconds. In this example, the Timeout Period parameter is set to 300. Note The timeout period is the period of time during which you can perform custom operations on ECS instances. If the timeout period is shorter than the period of time that is required to perform the custom operations, the operations may fail. We recommend that you estimate the period of time that is required to perform custom operations on ECS instances and configure the Timeout Period parameter based on your business requirements.
      Default Execution Policy	Select Continue.
      Send Notification When Lifecycle Hook Takes Effect	Specify a notification method or the action that you want Auto Scaling to perform after the lifecycle hook times out. In this example, perform the following operations: Select OOS Template. Select Public Templates. Select ACS-ESS-LifeCycleDetachNetworkInterfaceAndDeleteEip. In the ACS-ESS-LifeCycleDetachNetworkInterfaceAndDeleteEip public template, set OOSAssumeRole to OOSServiceRole. In Step 1: Grant OOS permissions to the RAM role, OOSServiceRole is granted the permissions on the ECS, Auto Scaling, and EIP resources. OOS obtains the preceding permissions after it assumes the RAM role.

6. Trigger a scale-in.

   In this example, a scale-out is manually triggered by executing a scaling rule. You can also trigger scale-outs by using scheduled or event-triggered tasks.

   Note

   If scaling activities are triggered when you manually execute scaling rules, lifecycle hooks take effect. However, lifecycle hooks do not take effect when you manually add or remove ECS instances to or from a scaling group.

   1. In the upper part of the scaling group details page, click the Scaling Rules and Event-triggered Tasks tab.

   2. Click the Scaling Rules tab, and then click Create Scaling Rule in the upper-right corner.

   3. In the Create Scaling Rule dialog box, configure parameters of the scaling rule and click OK.

      The following table describes the parameters that are used in this example. For parameters that are not described in the table, use the default settings.

      Parameter	Description
      Rule Name	Enter Delete1.
      Rule Type	Select Simple Scaling Rule.
      Operation	Set the value to Remove 1 Instances.

   4. Find the Delete1 scaling rule and click Execute in the Actions column.

   5. In the Execute Scaling Rule message, click OK.

   After the scaling rule is executed, Auto Scaling removes one ECS instance from the scaling group. However, the ECS instance enters the Pending Remove state because of the ESSHookForDeleteNicAndEip lifecycle hook that is in effect before the ECS instance is removed from the scaling group. During the timeout period of the lifecycle hook, Auto Scaling notifies OOS to execute the O&M operations that are defined in the ACS-ESS-LifeCycleDetachNetworkInterfaceAndDeleteEip public template.

7. Check whether the ENI is unbound from the ECS instance and the EIP of the ENI is released.

   You can go to the Network Interfaces page to check whether the ENI exists and the Elastic IP Addresses page to check whether the EIP exists. If the ENI and the EIP do not exist, the template takes effect.

   If the ECS instance is removed from the scaling group but the ENI or the EIP still exists, you can go to the OOS console to check the execution of the O&M operations. For more information, see Step 3: (Optional) View the OOS execution.

Step 3: (Optional) View the OOS execution

1. Log on to the OOS console.

2. In the left-side navigation pane, choose Automated Tasks > Task Execution Management.

3. Find the execution task by time and click Details in the Actions column.

4. On the execution details page, view information about the OOS execution.

   For example, in the Basic Information section, you can view the execution ID and status. In the Execution Result section, you can click a task node to view the execution details. For more information, see View the details of an execution.

   Note

   If an execution failed, the error message is displayed in the Execution Result section.

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