We’ve sometimes referred to the Netflix software architecture in AWS as our Rambo Architecture. Each system has to be able to succeed, no matter what, even all on its own. We’re designing each distributed system to expect and tolerate failure from other systems on which it depends.
If our recommendations system is down, we degrade the quality of our responses to our customers, but we still respond. We’ll show popular titles instead of personalized picks. If our search system is intolerably slow, streaming should still work perfectly fine.
One of the first systems our engineers built in AWS is called the Chaos Monkey. The Chaos Monkey’s job is to randomly kill instances and services within our architecture. If we aren’t constantly testing our ability to succeed despite failure, then it isn’t likely to work when it matters most – in the event of an unexpected outage.
Which, let’s face it, seems like insane advice at first glance. I’m not sure many companies even understand why this would be a good idea, much less have the guts to attempt it. Raise your hand if where you work, someone deployed a daemon or service that randomly kills servers and processes in your server farm.
Now raise your other hand if that person is still employed by your company.
Who in their right mind would willingly choose to work with a Chaos Monkey?