Auto Scaling:Automatically add and remove ECS instances from a PolarDB cluster whitelist

Procedure

In this example, a public OOS template named ACS-ESS-LifeCycleModifyPolarDBIPWhitelist is used to show how to automate the addition of instance IP addresses to the IP address whitelist of a PolarDB cluster during a scale-out event. Perform the following steps:

Step 1: Grant a RAM role the permissions on OOS

You must have the permissions to execute OOS templates. The ACS-ESS-LifeCycleModifyPolarDBIPWhitelist template includes ECS, Auto Scaling, and PolarDB resources that are required to perform O&M tasks.

1. Log on to the Resource Access Management (RAM) console.

2. Create a policy.

   1. In the navigation pane on the left, click Permission Management > Access Policies.

   2. Click Create Access Policy.

   3. On the Create Policy page, click the JSON tab, configure the parameters, and then click OK.

      The following table describes the settings that are used in this example. Any parameters not covered in the following table default to their predefined settings.

      Parameter	Description
      Name	Enter ESSHookPolicyForPolarDBWhitelist.
      Policy Document	Enter the following content: { "Version": "1", "Statement": [ { "Action": [ "ecs:DescribeInstances" ], "Resource": "*", "Effect": "Allow" }, { "Action": [ "polardb:DescribeDBClusterAccessWhitelist", "polardb:ModifyDBClusterAccessWhitelist" ], "Resource": "*", "Effect": "Allow" }, { "Action": [ "ess:CompleteLifecycleAction" ], "Resource": "*", "Effect": "Allow" } ] }

3. Attach the policy to the OOSServiceRole RAM role.

   1. In the navigation pane on the left, click Identity Management > Roles.

   2. Find OOSServiceRole and click Add Permissions in the Actions column.

      Grant the required permissions to the OOSServiceRole RAM role.

   3. On the Grant Permission page, configure the resource scope and policy, and then click Grant Permission.

      The following table describes the settings that are used in this example. Any parameters not covered in the following table default to their predefined settings.

      Parameter	Description
      Resource Scope	Set the value to Account.
      Policies	Select the following custom policy: ESSHookPolicyForPolarDBWhitelist.

Step 2: Create a lifecycle hook for scale-out purposes and trigger a scale-out event

1. Log on to the Auto Scaling console.

2. In the navigation pane on the left, click Scaling Groups.

3. In the top navigation bar, select a region.

4. Find the scaling group that you want to manage and open its details page in one of the following ways:

   • In the Scaling Group Name/ID column, click the ID of the scaling group.

   • In the Actions column, click Details.

5. Create a lifecycle hook.

   1. At the top of the page, click the Event and adhesive hook tab.

   2. Click Create Lifecycle Hook.

   3. Configure the lifecycle hook parameters and click OK.

      The following table describes the settings that are used in this example. Any parameters not covered in the following table default to their predefined settings.

      Parameter	Description
      Name	Enter ESSHookForAddPolarDBWhitelist.
      Scaling Activity Type	Select Scale-Out.
      Timeout Period	Configure Timeout Period based on your business requirements. In this example, set the value to 300. Unit: seconds. Note The timeout period is the period of time during which you can perform custom operations on instances. If the timeout period is shorter than the period of time that is required to perform custom operations, the operations may fail. We recommend that you estimate the period of time that is required to perform custom operations on instances and configure Timeout Period based on your estimations.
      Default Execution Policy	Select Continue.
      Send Notification When Lifecycle Hook Takes Effect	Configure the following parameters for the template: Notification Method: Select OOS Template. OOS Template Type: Select Public Templates. Select ACS-ESS-LifeCycleModifyPolarDBIPWhitelist. In the ACS-ESS-LifeCycleModifyPolarDBIPWhitelist public template, you must also configure the following parameters: dbClusterId: Enter the ID of the PolarDB cluster. modifyMode: Select Append. This value applies to the scale-out event during which Auto Scaling adds the private IP addresses of your ECS instances to the IP address whitelist of the PolarDB cluster. OOSAssumeRole: Select OOSServiceRole. In Step 1, OOSServiceRole is granted the permissions on the ECS, Auto Scaling, and PolarDB resources. OOS obtains the preceding permissions after it assumes the RAM role.

6. Trigger a scale-out event.

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

   Note

   If scaling events 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. Click the Scaling Rules and Event-triggered Tasks tab.

   2. On the Scaling Rules tab, click Create Scaling Rule.

   3. Set the properties for the scaling rule and click OK.

      The following table describes the settings that are used in this example. Any parameters not covered in the following table default to their predefined settings.

      Parameter	Description
      Rule Name	Enter Add1.
      Rule Type	Select Simple Scaling Rule.
      Operation	Set the value to Add 1 Instances.

   4. In the list of scaling rules, find the Add1 rule that you created and click Recurrently in the Actions column.

   5. Click OK.

   After the scaling rule is executed, Auto Scaling adds one ECS instance to the scaling group. However, the ECS instance enters the Pending Add state because of the ESSHookForAddPolarDBWhitelist lifecycle hook that is in effect. During the timeout period of the lifecycle hook, Auto Scaling notifies OOS to execute the O&M tasks that are defined in the ACS-ESS-LifeCycleModifyPolarDBIPWhitelist public template.

Step 3: Check the IP address whitelist of the PolarDB cluster

1. Log on to the PolarDB console.

2. In the navigation pane on the left, click Clusters.

3. Find the PolarDB cluster and click its ID in the Cluster ID/Name column.

4. In the navigation pane on the left, click Settings and Management > Cluster Whitelist.

   • If the private IP address of the ECS instance is added to the IP address whitelist of the PolarDB cluster, the ACS-ESS-LifeCycleModifyPolarDBIPWhitelist public template takes effect.

   • If the ECS instance is created but its private IP address is not added to the IP address whitelist of the PolarDB cluster, go to the OOS console to view the execution of the O&M tasks. For more information, see Step 4: (Optional) View the OOS execution.

Step 4: (Optional) View the OOS execution

1. Log on to the OOS console.

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

3. Find the execution based on the start time and click Details in the Actions column.

4. On the execution details page that appears, view the related information.

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

   Note

   If the execution fails, an error message is displayed on the execution details page.

FAQ