Auto Scaling:Apply an automatic snapshot policy to ECS instances

Create the policy

1. Log on to the RAM console.

2. In the left-side navigation pane, choose Grant Permission > Policies.

3. Click Create Policy.

4. On the Create Policy page, click the JSON tab and enter the following policy content:

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

5. Click OK.

6. In the Create Policy dialog box, enter a policy name and description, then click OK.

   This tutorial uses ESSHookPolicyForApplyAutoSnapshotPolicy as the policy name.

   To modify the policy content, click Cancel to return to the JSON tab.

Attach the policy to the RAM role

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

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

3. In the Grant Permission panel, configure the following parameters and click Grant Permission:

   Parameter	Setting
   Resource scope	Account
   Policies	ESSHookPolicyForApplyAutoSnapshotPolicy

Create the lifecycle hook

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 a region.

4. Find the scaling group and open its details page by clicking its ID in the Scaling Group Name/ID column or by clicking Details in the Actions column.

5. Click the Lifecycle Hook tab, then click Create Lifecycle Hook.

6. Configure the following parameters and click OK:

   Parameter	Setting
   Name	ESSHookForApplyAutoSnapshotPolicy
   Scaling activity	Scale-out Event
   Timeout period	300 (adjust based on how long the OOS template takes to run)
   Default execution policy	Continue
   Send notification when lifecycle hook takes effect	Select OOS Template > Public Templates > ACS-ESS-LifeCycleApplyAutoSnapshotPolicy

   In the ACS-ESS-LifeCycleApplyAutoSnapshotPolicy template parameters:

   • AutoSnapshotPolicyId: Enter the ID of your automatic snapshot policy.

   • OOSAssumeRole: Select OOSServiceRole.

   Set the timeout period long enough to cover the full OOS template execution. If the timeout is too short, OOS may not finish applying the snapshot policy before the hook expires.

Trigger a scale-out event

This tutorial triggers a scale-out event by manually executing a scaling rule. You can also use scheduled tasks or event-triggered tasks.

Lifecycle hooks take effect when scaling rules are executed. They do not take effect when you manually add ECS instances to a scaling group.

1. On the scaling group details page, click the Scaling Rules and Event-triggered Tasks tab.

2. Click the Scaling Rules tab, then click Create Scaling Rule.

3. Configure the following parameters and click OK:

   Parameter	Setting
   Rule name	Add1
   Rule type	Simple Scaling Rule
   Operation	Add 1 Instances

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

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

   Auto Scaling adds one ECS instance to the scaling group. The ESSHookForApplyAutoSnapshotPolicy lifecycle hook puts the instance in the Pending Add state. Auto Scaling then signals OOS to run the ACS-ESS-LifeCycleApplyAutoSnapshotPolicy template and apply the snapshot policy.

Verify the result

1. On the scaling group details page, click the Instances tab.

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

3. On the instance details page, click the Block Storage (Disks) tab.

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

Success: The Automatic Snapshot Policy toggle is on and shows the policy you specified in the OOS template.

Failure: The toggle is off. Check the OOS execution to find out why — see (Optional) Step 3: View OOS execution status below.