AWS - Autoscaling Troubleshooting

Exam Question Scenario :- 
EC2 instances fail to launch with Autoscaling configuration

Description :-
Autoscaling configuration requires the following :-

Autoscaling launch configuration which allows you to select an 

• AMI
• Instance type
• IAM role (optional)
• Security group
• Key pair file

Autoscaling group configuration allows you to select AZ to be used to launch the EC2 instances with the selected launch configuration

 Troubleshooting key points :-

1. AMI id does not exist or is still pending and cannot be used to launch instances
2. Security group provided in the launch configuration does not exist
3. Key pair associated with the EC2 instance does not exist
4. Autoscaling group not found or is incorrectly configured
5. AZ configured with the Autoscaling group is no longer supported cause it might not be available
6. Invalid EBS block device mappings
7. Instance type is not supported in the AZ
8. Capacity limits reached either cause of the restriction on the number of instance type that can be launched in a region or cause AWS is not able to provision the specified instance type in the AZ (for e.g. no more spot instances or On-demand instances availability)

More details @ AWS Autoscaling Developer Guide