# State change events for Amazon EC2 instances
<a name="monitoring-instance-state-changes"></a>

Amazon EC2 sends an `EC2 Instance State-change Notification` event to Amazon EventBridge when the state of an instance changes.

The following is example data for this event. In this example, the instance entered the `pending` state.

```
{
   "id":"7bf73129-1428-4cd3-a780-95db273d1602",
   "detail-type":"EC2 Instance State-change Notification",
   "source":"aws.ec2",
   "account":"123456789012",
   "time":"2021-11-11T21:29:54Z",
   "region":"us-east-1",
   "resources":[
      "arn:aws:ec2:us-east-1:123456789012:instance/i-1234567890abcdef0"
   ],
   "detail":{
      "instance-id":"i-1234567890abcdef0",
      "state":"pending"
   }
}
```

The possible values for `state` are:
+ `pending`
+ `running`
+ `stopping`
+ `stopped`
+ `shutting-down`
+ `terminated`

When you launch or start an instance, it enters the `pending` state and then the `running` state. When you stop an instance, it enters the `stopping` state and then the `stopped` state. When you terminate an instance, it enters the `shutting-down` state and then the `terminated` state. For more information, see [Amazon EC2 instance state changes](ec2-instance-lifecycle.md).

# Create an alarm that sends an email when an Amazon EC2 instance changes state
<a name="ec2-events-eventbridge-example"></a>

To receive email notifications when your instance changes state, create an Amazon SNS topic and then create an EventBridge rule for the `EC2 Instance State-change Notification` event.

**To create an SNS topic**

1. Open the Amazon SNS console at [https://console.aws.amazon.com/sns/v3/home](https://console.aws.amazon.com/sns/v3/home).

1. In the navigation pane, choose **Topics**.

1. Choose **Create topic**.

1. For **Type**, choose **Standard**.

1. For **Name**, enter a name for your topic.

1. Choose **Create topic**.

1. Choose **Create subscription**.

1. For **Protocol**, choose **Email**.

1. For **Endpoint**, enter the email address that receives the notifications.

1. Choose **Create subscription**.

1. You'll receive an email message with the following subject line: AWS Notification - Subscription Confirmation. Follow the directions to confirm your subscription.

**To create an EventBridge rule**

1. Open the Amazon EventBridge console at [https://console.aws.amazon.com/events/](https://console.aws.amazon.com/events/).

1. Choose **Create rule**.

1. For **Name**, enter a name for your rule.

1. For **Rule type**, choose **Rule with an event pattern**.

1. Choose **Next**.

1. For **Event pattern**, do the following:

   1. For **Event source**, choose **AWS services**.

   1. For **AWS service**, choose **EC2**.

   1. For **Event type**, choose **EC2 Instance State-change Notification**.

   1. By default, we send notifications for any state change for any instance. If you prefer, you can select specific states or specific instances.

1. Choose **Next**.

1. Specify a target as follows:

   1. For **Target types**, choose **AWS service**.

   1. For **Select a target**, choose **SNS topic**.

   1. For **Topic**, choose the SNS topic that you created in the previous procedure.

1. Choose **Next**.

1. (Optional) Add tags to your rule.

1. Choose **Next**.

1. Choose **Create rule**.

1. To test your rule, initiate a state change. For example, start a stopped instance, stop a running instance, or launch an instance. You'll receive email messages with the following subject line: AWS Notification Message. The body of the email contains the event data.