Hi,
We're in the planning phases of implementing an Amazon cluster for a particular workflow. We think volume will be such that it will make sense to have at least a the manager and a worker node running working all of the time and will be albe to reduce costs by using the reserved instance pricing. However, we have some questions about how auto scaling works with regards to stopping vs. terminating worker nodes. In my brief experience working with CloudMan I've been able to determine that allocating instances that use EBS volumes accrues charges. With the 15GB EBS volume currently allocated by the CloudMan AMI, starting a new worker node costs $1.50. So if I start a worker node, terminate it and start another one I get charged $3.00. However, if I start an instance, stop it and restart it I only get charged $1.50 for the initial allocation and I do not get charged for restarting it. Also, to my understanding (help me if I'm wrong here because my experience is limited) I don't get charged for the time where the volume is still mounted on EBS, but the instance is not running. I have a few questions regarding this.
1) For those with more experience with Amazon's pricing, is my scenario correct? 2) Will the autoscaling of nodes terminate unused nodes or simply stop them? 3) If autoscaling terminates nodes, is it possible to stop and restart nodes within the cluster and not terminate them and still have CloudMan utilize them in the cluster appropriately?
Thanks!