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Summary of the Amazon S3 Service Disruption

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Re: Summary of the Amazon S3 Service Disruption

#82
Something that wasn't addressed -- there seems to be an architectural issue with ELB where ELBs with S3 access logs enabled had instances fail ELB health checks, presumably while the S3 API was returning 5XX. My load balancers in us-east-1 without access logs enabled were fine throughout this event. Has there been any word on this?

Re: Summary of the Amazon S3 Service Disruption

#83
post #8

> At 9:37AM PST, an authorized S3 team member using an established playbook executed a command which was intended to remove a small number of servers for one of the S3 subsystems that is used by the S3 billing process. Unfortunately, one of the inputs to the command was entered incorrectly and a larger set of servers was removed than intended. It remains amazing to me that even with all the layers of automation, the…

Automation tends to make those kinds of errors worse rather than better. Perhaps more infrequent and of a different nature than before, but screwing up an automated action cascades much, much faster than a human initiated one. As a result, you have to watch things a good deal closer and build in more and tighter safe guards.

For instance: https://thenextweb.com/shareables/2014/05/16/emory-universit...

Note: Automation is great, you just can't be sloppy with it. EVER.

edit:fix minor typo

Re: Summary of the Amazon S3 Service Disruption

#85
post #8

> At 9:37AM PST, an authorized S3 team member using an established playbook executed a command which was intended to remove a small number of servers for one of the S3 subsystems that is used by the S3 billing process. Unfortunately, one of the inputs to the command was entered incorrectly and a larger set of servers was removed than intended. It remains amazing to me that even with all the layers of automation, the…

Or the root cause is a UI that allows mistakes like these.

Is it possible to build a UI that will not allow you to make a mistake?

If the computer knows exactly what actions would be a mistake, why can't it just do the correct actions (those that aren't a mistake) automatically?

Re: Summary of the Amazon S3 Service Disruption

#86
Really pleased to see this, it's good to see an organisation that's being transparent (and maybe given us a little peek under the hood of how S3 is architected) and most importantly they seem quite humbled.

It would be easy for an arrogant organisation to fire or negatively impact the person that made the mistake, I hope Amazon don't fall into that trap and focus instead on learning from what happened, closing the book and move on.

Re: Summary of the Amazon S3 Service Disruption

#87
post #25

Earlier quoted context omitted.

Wonder what happened to the poor slob who did that. He/She was unauthorized AND caused a pretty serious outage... EDIT: derp, my bad, I read as "unauthorized" which was "authorized".

One of the positive things about Amazon's culture is that they heavily emphasize blaming broken processes, not blaming people. I doubt the person involved will have any negative consequences beyond embarrassment.

Can you imagine the feeling? I once sent a debug email to our mailing list and felt terrible for days. Imagine bringing down the internet...

Re: Summary of the Amazon S3 Service Disruption

#88
post #68

TLDR; Someone on the team ran a command by mistake that took everything down. Good, detailed description. It happens. Out of all of Amazon's offerings, I still love S3 the most.

"It happens" is the only reasonable takeaway you can get from a postmortem like this. My worry is that people read it and go "I am aghast that such a command can be run!" without knowing that little commands like that are run numerous times a day without incident. The only thing I read in there and go "hmmm" is that it took quite that long for the S3 service to recover, and that the status page wasn't hosted on someo…

People need to realize when they go to the cloud it's not that 'it happens', it's that it will happen, and you have no ability to do anything about it. Fact of life and risk management.

Re: Summary of the Amazon S3 Service Disruption

#89
post #67

Not as interesting an explanation as I was hoping for. Someone accidentally typed "delete 100 nodes" instead of "delete 10 nodes" or something. It sounds like the weakness in the process is that the tool they were using permitted destructive operations like that. The passage that stuck out to me: "in this instance, the tool used allowed too much capacity to be removed too quickly. We have modified this tool to remove…

I always wonder about unintended consequences of this sort of thing. Like someday there will be a worm about to rampage through their servers and someone says, "take them all offline now!" and the answer is, "we can't because of the throttle safeguard we put in place after incident XYZ, it will be about 17 hours..."

Which is why there needs to be an override switch, but it needs to be very very explicit that you are going past the safeguards. And only a limited number of people who can use that override.

Re: Summary of the Amazon S3 Service Disruption

#90
post #21
post #17

This part is also interesting: > While this is an operation that we have relied on to maintain our systems since the launch of S3, we have not completely restarted the index subsystem or the placement subsystem in our larger regions for many years. These sorts of things make me understand why the Netflix "Chaos Gorilla" style of operating is so important. As they say in this post: > We build our systems with the assu…

I think you meant "Chaos Monkey" [1]. [1] https://github.com/Netflix/chaosmonkey

They have an entire simian army of chaos for the purposes of simulated destruction of their network.
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