I heard (perhaps wrongly) that using an Amazon Elastic IP "EIP" on a network interface and attaching that to an EC2 instance might be a quicker way of bringing up (or switching to) a new machine.
However I am little confused how to handle the networking once the new
eth1 is attached. Do people have a eth1 systemd networkd rule with a low
RouteMetric or do they remove eth0, or they just alter the route or am I missing a trick?
Ultimately since ELB can't have a static IP address, I am looking for ways of making sure EC2 can be quickly provisioned to avoid down time.