Amazon autoscaling scale-down instance

Question

I am learning and setting up auoscale configuration for our production application. I want to know while setting scale-down which instance id to use. e.g. my configuration uses maximum number of instances as 3. I can put scale-up policy on instance id 1, but how can I put scale down policy for instance 2 and instance 3 which are still to be started. PS: I understand for 2 instances, I can put policy on instance 1 and it will go down if load subsides.

Answer 1

you need to specify ami id for template ami only. all will be scaled up and down based on this single ami id. PLEASE NOTE: it is an ami id or image id that will be utilized and not an instance id.

The scale will be a range from 1 to 3 and will be configured in your autoscaling group with these tags: --min-size 1 --max-size 3 based on the metrics that you supply in the autoscaling policy.

With a minimum size of 1 instance, 1 instance will always be running. With a maximum size of 3 instances, 3 can run. There is not a need to scale non running instances.

Here is a complete tutorial: http://www.cardinalpath.com/autoscaling-your-website-with-amazon-web-services-part-2/