Troubleshoot issues in Amazon EC2 Auto Scaling

Amazon EC2 Auto Scaling provides specific and descriptive errors to help you troubleshoot issues. You can find the error messages in the description of the scaling activities.

Retrieve an error message from scaling activities

To retrieve an error message from the description of scaling activities, use the describe-scaling-activities command. You have a record of scaling activities that dates back 6 weeks. Scaling activities are ordered by start time, with the latest scaling activities listed first.

To see the scaling activities for a specific Auto Scaling group, use the following command.

aws autoscaling describe-scaling-activities --auto-scaling-group-name my-asg

The following is an example response, where StatusCode contains the current status of the activity and StatusMessage contains the error message.

{
    "Activities": [
        {
            "ActivityId": "3b05dbf6-037c-b92f-133f-38275269dc0f",
            "AutoScalingGroupName": "my-asg",
            "Description": "Launching a new EC2 instance: i-003a5b3ffe1e9358e.  Status Reason: Instance failed to complete user's Lifecycle Action: Lifecycle Action with token e85eb647-4fe0-4909-b341-a6c42d8aba1f was abandoned: Lifecycle Action Completed with ABANDON Result",
            "Cause": "At 2021-01-11T00:35:52Z a user request created an AutoScalingGroup changing the desired capacity from 0 to 1.  At 2021-01-11T00:35:53Z an instance was started in response to a difference between desired and actual capacity, increasing the capacity from 0 to 1.",
            "StartTime": "2021-01-11T00:35:55.542Z",
            "EndTime": "2021-01-11T01:06:31Z",
            "StatusCode": "Cancelled",
            "StatusMessage": "Instance failed to complete user's Lifecycle Action: Lifecycle Action with token e85eb647-4fe0-4909-b341-a6c42d8aba1f was abandoned: Lifecycle Action Completed with ABANDON Result",
            "Progress": 100,
            "Details": "{\"Subnet ID\":\"subnet-5ea0c127\",\"Availability Zone\":\"us-west-2b\"...}",
            "AutoScalingGroupARN": "arn:aws:autoscaling:us-west-2:123456789012:autoScalingGroup:283179a2-f3ce-423d-93f6-66bb518232f7:autoScalingGroupName/my-asg"
        },
     ...
    ]
}

For a description of the fields in the output, see Activity in the Amazon EC2 Auto Scaling API Reference.

To view scaling activities for a deleted group

To view scaling activities after the Auto Scaling group has been deleted, add the --include-deleted-groups option to the describe-scaling-activities command as follows.

aws autoscaling describe-scaling-activities --auto-scaling-group-name my-asg --include-deleted-groups

The following is an example response, with a scaling activity for a deleted group.

{
    "Activities": [
        {
            "ActivityId": "e1f5de0e-f93e-1417-34ac-092a76fba220",
            "AutoScalingGroupName": "my-asg",
            "Description": "Launching a new EC2 instance.  Status Reason: Your Spot request price of 0.001 is lower than the minimum required Spot request fulfillment price of 0.0031. Launching EC2 instance failed.",
            "Cause": "At 2021-01-13T20:47:24Z a user request update of AutoScalingGroup constraints to min: 1, max: 5, desired: 3 changing the desired capacity from 0 to 3.  At 2021-01-13T20:47:27Z an instance was started in response to a difference between desired and actual capacity, increasing the capacity from 0 to 3.",
            "StartTime": "2021-01-13T20:47:30.094Z",
            "EndTime": "2021-01-13T20:47:30Z",
            "StatusCode": "Failed",
            "StatusMessage": "Your Spot request price of 0.001 is lower than the minimum required Spot request fulfillment price of 0.0031. Launching EC2 instance failed.",
            "Progress": 100,
            "Details": "{\"Subnet ID\":\"subnet-5ea0c127\",\"Availability Zone\":\"us-west-2b\"...}",
            "AutoScalingGroupState": "Deleted",
            "AutoScalingGroupARN": "arn:aws:autoscaling:us-west-2:123456789012:autoScalingGroup:283179a2-f3ce-423d-93f6-66bb518232f7:autoScalingGroupName/my-asg"
        },
     ...
    ]
}

Turn off scaling activities

You have the following options if you need to investigate an issue without interference from scaling policies or scheduled actions:

Additional troubleshooting resources

The following pages provide additional information for troubleshooting issues with Amazon EC2 Auto Scaling.

The following AWS resources can also be of help:

Troubleshooting often requires iterative query and discovery by an expert or from a community of helpers. If you continue to experience issues after trying the suggestions in this section, contact AWS Support (in the AWS Management Console, click Support, Support Center) or ask a question on AWS re:Post using the Amazon EC2 Auto Scaling tag.