I'd love to recommend pingdom, or a service like it. I'm in no way affiliated with them, just a very happy customer and one of those products where I'm jelly I didn't come up with the idea. It integrates very nicely with pagerduty and slack/sms, etc.
It's just extra redundancy in case something like cloudwatch (which you should use -- with ELBs) also goes down.
It's just extra redundancy in case something like cloudwatch (which you should use -- with ELBs) also goes down.