When you are using Kubernetes, you won't have to deal with this yourself. The Cluster will move pods from nodes that are stopped because the spot price is exceeded. Ideally place nodes at different bids. So there will be a performance hit but no outage. With the new AWS start/stop feature [1] nodes will come up again when the spot price sinks.
1) https://aws.amazon.com/about-aws/whats-new/2017/09/amazon-ec...