use a change set to update a stack - Resource Orchestration Service

A change set can help you preview the impacts of a change operation on a stack before you update the stack. This topic describes how to use a change set to update a stack in Resource Orchestration Service (ROS).

Scenario

If you want to preview the impacts of changes to a stack before you update the stack resources, you can update the stack by using a change set. For example, you can preview whether key resources are deleted or replaced by a stack update. You can create a change set to update the stack. The change set helps you preview impacts of the update operation on the stack before the stack update takes effect. The stack update takes effect only after you successfully execute the change set on the stack. Before you execute a change set, you can check and modify the template of the stack that you want to update to meet your business requirements.

Prerequisites

A stack is created. For more information, see Create a stack.

Limits

You can create a change set only for a stack that is in one of the following states.

State	Description
CREATE_COMPLETE	The stack is created.
UPDATE_FAILED	The stack fails to be updated.
UPDATE_COMPLETE	The stack is updated.
ROLLBACK_COMPLETE	The resources of the stack are rolled back.
ROLLBACK_FAILED	The resources of the stack fail to be rolled back.
IMPORT_CREATE_COMPLETE	The stack is created by using imported resources.
IMPORT_UPDATE_COMPLETE	The stack is updated by using imported resources.
IMPORT_UPDATE_FAILED	The stack fails to be updated by using imported resources.
IMPORT_UPDATE_ROLLBACK_COMPLETE	The resources are rolled back after the stack fails to be updated by using imported resources.
IMPORT_UPDATE_ROLLBACK_FAILED	The resources fail to be rolled back after the stack fails to be updated by using imported resources.
CHECK_FAILED	The stack fails to be validated.
CHECK_COMPLETE	The stack is validated.

Supported methods

ROS console: You can use a change set to update a stack in the ROS console.
For more information, see the "Update a stack in the ROS console" section of this topic.
ROS API operation: You can use a change set to update a stack by calling a specific ROS API operation.
For more information, see CreateChangeSet.
Alibaba Cloud CLI: You can use a change set to update a stack by using Alibaba Cloud CLI.
For more information, see the "Update a stack by using Alibaba Cloud CLI" section of this topic.

Update a stack in the ROS console

Log on to the ROS console.
In the left-side navigation pane, click Stacks.
In the top navigation bar, select the region where the stack you want to manage resides from the region drop-down list. For example, select China (Hangzhou).
On the Stacks page, find the stack and click the stack ID.
On the stack details page, click the Change Sets tab.
On the Change Sets tab, click Create Change Set.
In the Select Template step, select an existing template or a sample template based on your business requirements, and click Next.
In the Configure Parameters step, configure the Change Set Name parameter and parameters in the Configure Template Parameters section.
Note
Parameters in the Configure Template Parameters section are parsed from the template. Follow the on-screen instructions to configure the template parameters.
In the Configure Change Set section, configure the Stack Policy, Rollback on Failure, Timeout Period, Maximum Concurrent Resources, RAM Role, and Whether to enable replacement update parameters. Then, click Next.
In the Check and Confirm step, click Create Change Set.

Update a stack by using Alibaba Cloud CLI

Install Alibaba Cloud CLI.
For more information, see Windows.
Configure an Alibaba Cloud credential.
For more information, see Configure a credential in interactive mode (fast).
Update a stack by creating a change set.
Run the aliyun ros CreateChangeSet command to update a stack by creating a change set.
You must set the type of the change set to UPDATE and specify the stack name, region ID, template, and change set name. For more information, see CreateChangeSet.
```
aliyun ros CreateChangeSet --ChangeSetType UPDATE --StackName <Stack name> --RegionId <Region ID of the change set> --TemplateBody <Structure that contains the template body> --ChangeSetName <Change set name> 
```
Run the aliyun ros ExecuteChangeSet command to execute the change set.
```
aliyun ros ExecuteChangeSet --ChangeSetId <Change set +ID>
```

What to do next

You can view the impacts of a change set on a stack and check the stack template. For more information, see View a change set and Data structures.
After you execute a change set on a stack, ROS automatically deletes other change sets that are associated with the stack. For more information, see Execute a change set.
If a change set cannot meet your business requirements on a stack update, you can delete the change set. For more information, see Delete a change set.