Auto Scaling can notify you whenever a scaling event occurs in your scaling group — so you can monitor group activity and automate operations without polling. Notifications are delivered to CloudMonitor, a Message Service (MNS) topic, or an MNS queue.
This topic covers how to create, modify, delete, and view event notification rules.
Prerequisites
If you want to send messages to an MNS topic or queue, you must first create the MNS topic and MNS queue. Ensure that they are in the same region as the scaling group.
Before you begin, make sure that you have:
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An Auto Scaling group
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(For MNS targets) An MNS topic or queue in the same region as the scaling group. See Create a topic or Create a queue
Usage notes
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Each scaling group supports a maximum of 6 event notification rules.
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Each rule must use a unique notification target. Two rules in the same scaling group cannot share the same CloudMonitor resource, MNS topic, or MNS queue.
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After a rule is created, its Notification Method cannot be changed.
Choose a notification method
| Notification method | What it does |
|---|---|
| CloudMonitor | Sends Auto Scaling events to CloudMonitor as system events |
| MNS Topic | Publishes event messages to an MNS topic, which fan-outs to subscribers |
| MNS Queue | Sends event messages to an MNS queue for pull-based consumption |
For more information, see Overview.
Create an event notification rule
Each scaling group supports a maximum of 6 event notification rules.
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Log on to the Auto Scaling console.
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In the left-side navigation pane, click Scaling Groups.
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In the top navigation bar, select the region where Auto Scaling is activated.
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Find the target scaling group and go to its details page:
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Click the scaling group ID in the Scaling Group Name/ID column, or
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Click Details in the Actions column.
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Click the Notification Rules tab.
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Click Create Advanced Rule.
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Configure the following parameters:
Parameter Description Notification Method Select a notification target: CloudMonitor, MNS Topic, or MNS Queue. For details on each option, see Choose a notification method. Event Select the event types that trigger a notification. See Supported event types for descriptions of each event. -
Click OK.
Supported event types
| Event | Description |
|---|---|
| Successful Scale-out | All Elastic Compute Service (ECS) instances or elastic container instances (ECI) were added to the scaling group. |
| Successful Scale-in | All ECS instances or elastic container instances were removed from the scaling group. |
| Scale-out Failed | A scale-out was triggered, but ECS instances or elastic container instances were not added to the scaling group. |
| Scale-in Failed | A scale-in was triggered, but ECS instances or elastic container instances were not removed from the scaling group. |
| Scaling Request Rejected | Auto Scaling received a scaling request but rejected it because trigger conditions were not met. |
| Scale-out Started | A scale-out was triggered, and ECS instances or elastic container instances have started being added to the scaling group. |
| Scale-in Started | A scale-in was triggered, and ECS instances or elastic container instances have started being removed from the scaling group. |
| Scheduled Task Expired | A scheduled task is about to expire. Auto Scaling sends daily notifications starting 7 days before expiration. If a recurrence is configured, the expiration time is the last time when the task is executed. |
| Scaling Group Diagnosis | Auto Scaling has diagnosed the scaling group's health. Diagnosed items include: critical resource status, resource quota usage, resource billing status, and resource inventory status. |
| Partially Successful Scale-out | A scale-out was triggered, but not all ECS instances or elastic container instances were added to the scaling group. |
| Partially Successful Scale-in | A scale-in was triggered, but not all ECS instances or elastic container instances were removed from the scaling group. |
Modify an event notification rule
After a rule is created, only the Event parameter can be changed. The Notification Method is fixed.
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Log on to the Auto Scaling console.
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In the left-side navigation pane, click Scaling Groups.
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In the top navigation bar, select the region where Auto Scaling is activated.
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Find the target scaling group and go to its details page.
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Click the Notification Rules tab.
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Find the rule and click Edit in the Actions column.
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In the Edit Notification dialog box, update the Event parameter.
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Click OK.
Delete an event notification rule
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Log on to the Auto Scaling console.
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In the left-side navigation pane, click Scaling Groups.
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In the top navigation bar, select the region where Auto Scaling is activated.
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Find the target scaling group and go to its details page.
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Click the Notification Rules tab.
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Find the rule and click Delete in the Actions column.
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In the Delete Event Notification dialog box, click OK.
View event notifications
Click the link in the Notification Method column to navigate to the corresponding console and check whether notifications are being received.
CloudMonitor: In the CloudMonitor console, go to Event Monitoring, select System Event, and filter by Auto Scaling. All Auto Scaling system events appear on the page.
MNS Topic: On the Topic List page of the MNS console, find the topic and check whether the Message Count column is increasing. If it is, new messages are being received. View message details on a subscription client of the topic.
MNS Queue: On the Queue List page of the MNS console, find the queue and check whether the Active Messages column is increasing. Click Receive Message in the Actions column to view message details.
What's next
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Overview — learn how the event notification feature works and review the full list of supported event types