Auto Scaling:Apply an automatic snapshot policy to ECS instances

Step 1: Grant a RAM role the permissions on OOS

You must have the permissions to execute OOS templates. The ACS-ESS-LifeCycleApplyAutoSnapshotPolicy public OOS template defines the ECS and Auto Scaling resources required to perform O&M operations.

1. Log on to the RAM console.

2. Create a policy.

   1. In the left-side navigation pane, choose Permissions > Policies.

   2. Click Create Policy.

   3. On the Create Policy page, click the JSON tab, enter the policy content, and then click Next to edit policy information.

      Sample policy:

      {
          "Version": "1",
          "Statement": [
              {
                  "Action": [
                      "ecs:DescribeDisks",
                      "ecs:ApplyAutoSnapshotPolicy",
                      "ecs:DescribeInstances"
                  ],
                  "Resource": "*",
                  "Effect": "Allow"
              },
              {
                  "Action": [
                      "ess:CompleteLifecycleAction"
                  ],
                  "Resource": "*",
                  "Effect": "Allow"
              }
          ]
      }

   4. In the Basic Information section, enter a policy name and check whether the policy content is valid.

      In this example, set the Name parameter to ESSHookPolicyForApplyAutoSnapshotPolicy.

      Note

      If you want to modify the policy content, click Back to edit policy document.

   5. Click OK.

3. Attach the policy to the OOSServiceRole RAM role.

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

   2. Find OOSServiceRole and click Grant Permission in the Actions column.

      Add the required permissions for the OOSServiceRole RAM role that is assumed by OOS to complete the authorization.

   3. In the Grant Permission panel, select the policy that you want to assign and click OK.

      The following table describes the parameters 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 ESSHookPolicyForApplyAutoSnapshotPolicy policy.

   4. After the authorization is complete, click OK.

Step 2: Create a lifecycle hook of the scale-out type and trigger a scale-out

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 of the scale-out type.

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

   2. Click Create Lifecycle Hook.

   3. Configure parameters based on your business requirements 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 ESSHookForApplyAutoSnapshotPolicy.
      Scaling Activity	Select Scale-out Event.
      Timeout Period	Configure the Timeout Period parameter based on your business requirements. In this example, set the Timeout Period parameter to 300. 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 the Timeout Period parameter based on your estimations.
      Default Execution Policy	Select Continue.
      Send Notification When Lifecycle Hook Takes Effect	In this example, perform the following operations: Select OOS Template. Select Public Templates. Select ACS-ESS-LifeCycleApplyAutoSnapshotPolicy. Configure the following parameters in the ACS-ESS-LifeCycleApplyAutoSnapshotPolicy public OOS template: AutoSnapshotPolicyId: Enter the ID of the automatic snapshot policy. OOSAssumeRole: Select OOSServiceRole. In Step 1, permissions on ECS and Auto Scaling resources are granted to the OOSServiceRole RAM role. OOS can obtain these permissions after it assumes the RAM role.

6. Trigger a scale-out.

   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 page that appears, click the Scaling Rules and Event-triggered Tasks tab.

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

   3. In the Create Scaling Rule dialog box, configure parameters based on your business requirements 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 Add1.
      Rule Type	Select Simple Scaling Rule.
      Operation	Set the value to Add 1 Instances.

   4. On the Scaling Rules tab, find the Add1 scaling rule and click Execute in the Actions column.

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

   After Add1 is executed, the system attempts to add one ECS instance to the scaling group. Due to the ESSHookForApplyAutoSnapshotPolicy lifecycle hook, the ECS instance enters the Pending Add state before it is added to the scaling group. During this period, Auto Scaling notifies OOS to execute the ACS-ESS-LifeCycleApplyAutoSnapshotPolicy template and complete the defined O&M operations.

7. Check whether the automatically created ECS instance meets your expectations.

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

   2. Find the automatically created ECS instance and click its ID in the ECS Instance ID/Name column.

   3. On the Instance Details page, click the Cloud Disk tab.

   4. Find the desired cloud disk and click Configure Automatic Snapshot Policy in the Actions column.

      • In the following figure, the Automatic Snapshot Policy switch is turned on. The applied snapshot policy is the policy specified in the ACS-ESS-LifeCycleApplyAutoSnapshotPolicy OOS public template when you created the lifecycle hook. This proves that the automatically created ECS instance meets your expectations.

      • If the ECS instance is created but has no automatic snapshot policy, go to the OOS console to check the execution of the O&M operations defined in the public template.

(Optional) Step 3: View the execution status of an OOS template

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 that appears, view the related information.

   For example, you can view the execution ID and status in the Basic Information section. You can also click a task node in the Execution Steps and Results section to view the execution 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.