Auto Scaling:Manually manage instances in a scaling group

Manually add instances to a scaling group

The procedure varies by instance type.

1. Log on to the Auto Scaling console.

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

3. Find the scaling group 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 View Details.

4. At the top of the page, click the Instance Management tab.

5. ECS and ECI instances

   Considerations

   Before you manually add an ECS or ECI instance, note the following:

   • You can add ECI instances only to ECI-type scaling groups, and ECS instances only to ECS-type scaling groups.

   • The configuration of a manually added instance, such as its instance type and image, is independent of the scaling group's scaling configuration and does not need to match.

   • Manually adding an ECS or ECI instance to a scaling group triggers a scaling activity. This activity is not subject to a cooldown period. For more information about cooldown periods, see Cooldown period.

   • Manually adding instances affects the instance count of the scaling group based on the following rules:

     • The minimum and maximum instance counts of the scaling group do not change.

     • Expected instance count (after adding) = Expected instance count (before adding) + Number of manually added instances.

     • Number of instances in group (before adding) + Number of manually added instances ≤ Maximum instance count.

       Important

       The operation fails if adding the instances causes either the total instance count or the expected instance count to exceed the group's maximum instance count.

       For example:

       Before adding instances	After adding instances
       Current scaling group scenario: Minimum instance count: 1 Maximum instance count: 6 Expected instance count: 3 Number of instances in group: 2	You can add a maximum of three instances. If you add three instances, the changes are as follows: Minimum instance count: 1 Maximum instance count: 6 Expected instance count: 6 Number of instances in group: 5

   Procedure

   The following steps use an ECS instance as an example. The procedure for adding an ECI instance is similar.

   1. Navigate to the Manually Added list.

   2. Click Add Existing Instance.

   3. In the Add Existing Instance dialog box, select the ECS instances that you want to add, and then click Add.

      If you select You can hand over the management of the lifecycle for the ECS instance to the scaling group., removing the instance from the scaling group during a scale-in also releases it. You can manually add subscription instances to a scaling group, but the scaling group cannot manage the lifecycle of subscription instances.

      Warning

      Ensure your account has a sufficient balance. If you have an overdue payment, all pay-as-you-go and preemptible instances are stopped or released. To learn how an overdue payment affects ECS instances in the scaling group, see Overdue payments.

      In the list of available instances on the left, select the target ECS instance, click the > button to move it to the list of selected instances on the right, and then click ADD.

      After the instances are added, you can view their information, such as progress and health status, on the Instances > Manually Added list.

   Managed instances

   You can use Cloud Assistant to register non-Alibaba Cloud servers as managed instances. Once registered, these servers can use various Alibaba Cloud services, such as Cloud Assistant, Auto Scaling, CloudOps Orchestration Service, and Alibaba Cloud DevOps. For more information, see Alibaba Cloud managed instances.

   1. Navigate to the Managed Instance list.

   2. Click Add Instance.

   3. In the Add Managed Instances dialog box, select the target ECS instance from the list of available instances on the left, click the > button to move it to the list of selected instances on the right, and then click Confirm

      After the instances are added, you can view their information, such as ID, name, status, and join time, in the Managed Instance list.

View instances in a scaling group

After adding instances, you can view them in the scaling group.

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, in the Actions column, click View Details.

5. At the top of the page, click the Instance Management tab.

6. View the ECS, ECI, or managed instances within the scaling group.

   Instances are displayed on different lists based on how they were created:

   Auto-created instances

   The Auto Created list displays the ECS or ECI instances that were automatically created by the scaling group. If an automatically created instance is deemed unhealthy, it is automatically removed from the scaling group and released.

   You can manually change the status of a created ECS instance or ECI instance. For example, you can set it to the standby state, set it to the protection state, remove it from the protection state, remove it from the scaling group, or release it. For more information, see Manually adjust instance status and Manually remove or delete an instance.

   Manually added instances

   The Manually Added list displays the ECS or ECI instances that you manually added to the scaling group. If a manually added instance is not in the Running state, Auto Scaling considers it unhealthy and automatically removes it from the scaling group. Whether the instance is released upon removal depends on its lifecycle management setting:

   • If the scaling group does not manage the instance's lifecycle, the instance is removed from the group but not released.

   • If the scaling group manages the instance's lifecycle, the instance is removed from the group and released.

   You can manually change the status of a created ECS instance or ECI instance. For example, you can set it to the standby state, set it to the protection state, remove it from the protection state, remove it from the scaling group, or release it. For more information, see Manually adjust instance status and Manually remove or delete an instance.

   Managed instances

   The Managed Instance list displays the managed instances that have been added to an ECS-type scaling group. Managed instance IDs start with mi-. Unlike Alibaba Cloud instances, managed instances do not support lifecycle hooks, load balancer association, or health checks.

   A scaling group does not manage the lifecycle of managed instances added to it. You can only manually remove the managed instance from the scaling group. The instance is not released when it is removed.

   Note

   For more information about how to manage managed instances by using Auto Scaling, see Monitor and automatically scale ECS instances and non-Alibaba Cloud instances.

Manually remove or delete instances

Considerations

You can manually remove or delete instances that you no longer need from a scaling group if the group is in the Enable state and has no ongoing scaling activities. Before you proceed, note the following:

• Manually removing or deleting an ECS or ECI instance triggers a scale-in activity. This activity is not subject to a cooldown period. For more information about cooldown periods, see Cooldown period.

• The operation fails if removing or deleting the instances would cause the total number of instances in the scaling group to fall below the minimum instance count.

• Managed instances can only be manually removed from a scaling group. They are not released when they are removed.

• Triggering a scaling activity does not guarantee its success. Check the scaling activity details to verify the outcome. For more information, see View the details of a scaling activity.

Procedure

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, in the Actions column, click View Details.

5. At the top of the page, click the Instance Management tab.

6. Navigate to the list that contains the instance you want to remove:

   • To select an automatically created ECS or ECI instance, navigate to the Auto Created list.

   • To select a manually added ECS or ECI instance, navigate to the Manually Added list.

   • To select a manually added managed instance, navigate to the Managed Instance list.

7. Manually remove or delete the instance.

   Actions	Steps
   Remove an ECS or ECI instance	For a single instance: Find the instance that you want to manage. In the Actions column, click >Remove from Scaling Group. For multiple instances: Select the instances that you want to manage. At the bottom of the instance list, click Remove from Scaling Group.
   Remove a managed instance	For a single instance: Find the instance that you want to manage. In the Actions column, click Remove from Scaling Group. For multiple instances: Select the instances that you want to manage. At the bottom of the managed instance list, click Remove from Scaling Group.
   Delete an ECS or ECI instance	For a single instance: Find the instance that you want to manage. In the Actions column, click >Delete Instance. For multiple instances: Select the instances that you want to manage. At the bottom of the instance list, click Delete Instance. Note Deleting an instance removes the ECS instance or ECI instance from the scaling group: pay-as-you-go ECS instances and ECI instances are released at the same time, while subscription ECS instances and ECI instances are only removed from the scaling group and are not automatically released. Whether you can delete a manually added ECS instance or ECI instance depends on its management status. For more information, see Auto-created instances.

8. Choose whether to select Modify Expected Number of Instances (selected by default), and then click OK.

   • If Modify Expected Number of Instances is selected, the expected instance count is reduced by the number of removed instances.

   • If Modify Expected Number of Instances is cleared, the expected instance count remains unchanged after the instance is removed.

   Note

   When you remove or delete an ECS or ECI instance, you can also select the Automatically disassociate the instance from CLB (formerly SLB) and ApsaraDB RDS instances option. If you select this option, Auto Scaling automatically removes the instance from the vServer groups or default server groups associated with the scaling group. It also removes the instance from the access whitelist of the ApsaraDB RDS instance.

Related documents

• You can manually adjust the status of instances in a scaling group, such as ECS instances, ECI instances, or managed instances, based on your business requirements. For example, you can change the status of an ECS instance in a scaling group to Stopped. During a scale-out, Auto Scaling prioritizes starting Stopped instances. For more information, see Manually adjust instance status.

• You can associate a scaling group with CLB instances. The CLB instances distribute incoming traffic across multiple instances in the scaling group to enhance service availability. For more information, see Add CLB instances to or remove CLB instances from a scaling group.

• After you associate a scaling group with an ApsaraDB RDS instance, the private IP addresses of ECS instances that are added to the scaling group are automatically added to the access whitelist of the ApsaraDB RDS instance. This allows for internal network communication between the ECS instances and the ApsaraDB RDS instance. For more information, see Add or remove ApsaraDB RDS instances for a scaling group.

• If an instance fails to be removed or deleted, you can identify the cause based on the error message and handle it accordingly. For more information, see Troubleshoot scaling activity exceptions.