Auto Scaling - removing instances

There are times when you need to scale down and auto scaling group. To find out the current configuration of your auto scaling group, issue this command:
aws autoscaling describe-auto-scaling-groups
            "AutoScalingGroupName": "reachforce-as-grp",

To scale down your configuration you can issue the commands to decrease the min and max size:
aws autoscaling update-auto-scaling-group --auto-scaling-group-name reachforce-as-grp --min-size 2
aws autoscaling update-auto-scaling-group --auto-scaling-group-name reachforce-as-grp --max-size 3

You will then see the instance go away on your AWS console.

AWS Auto Scaling for batch processing

Can I use Auto Scaling for scaling out a set of servers that run periodically (auto scaling of zero) ?  This is not the typical auto scaling use case but it is possible.  This would most likely be used for use cases such as batch processing where instances would be spun up to support processing that happens periodically.  Here are some ways to solve this use case:

• Auto Scaling, SQS and CloudWatch : You can but it would require to use AWS SQS with Auto Scaling and you would set up an alarm that uses SQS instead of CloudWatch or a custom metrics.  See more here:
  http://docs.aws.amazon.com/AutoScaling/latest/DeveloperGuide/as-using-sqs-queue.html
  It is possible to set up an auto scaling group with min EC2 size of ):
  http://docs.aws.amazon.com/AutoScaling/latest/DeveloperGuide/US_BasicSetup.html. You can issue this command: as-create-auto-scaling-group my-test-asg --launch-configuration my-test-lc --availability-zones us-east-1a --min-size 0 --max-size 10 --desired-capacity 1
• OpsWorks : OpsWorks provides a graphical tool for scheduling time-based auto scaling (e.g. “start an instance every Monday at 8:00am and shut it down at 5:00p.m.”).
• Auto Scaling and Cron : The auto scaling API supports a cron-style "recurrence" attribute for scheduled actions:
  
  
  http://docs.aws.amazon.com/AutoScaling/latest/APIReference/API_PutScheduledUpdateGroupAction.html