What has caused AWS outage today – and why did it make the internet fall apart?

Amazon Web Services (AWS) has had a bad day.

That’s how the boss of another big US tech firm Cloudflare put it – probably feeling very relieved that today’s outage, hitting over 1,000 companies and affecting millions of internet users, had nothing to do with him.

The places hit by the outage vary significantly. It took out major social media platforms like Snapchat and Reddit, banks like Lloyds and Halifax, and games like Roblox and Fortnite.

AWS is a US giant with a large global footprint, having positioned itself as the backbone of the internet.

It provides tools and computers which enable around a third of the internet to work, it offers storage space and database management, it saves firms from having to maintain their own costly set-ups, and it also connects traffic to those platforms.

That’s how it sells its services: let us look after your business’s computing needs for you.

But today something very mundane went very wrong: a common kind of outage known as a Domain Name System (DNS) error.

People who work in the tech industry will be rolling their eyes right now.

This common error can cause a lot of havoc.

“It’s always DNS!” is something I hear a lot.

When someone taps an app or clicks a link, their device is essentially sending a request to be connected to that service.

DNS is supposed to act like a map, and today AWS lost its bearings – platforms like Snapchat, Canva and HMRC were all still there but it couldn’t see where they were to direct traffic to them.

These errors happen for a number of reasons.

Usually it’s a maintenance issue or a server failure. Sometimes that’s human error, someone misconfiguring something somewhere, or in extreme cases a cyber attack – although there’s no evidence of this so far.

AWS said it occurred at its vast data centre plant in North Virginia, its oldest and biggest site.

A chorus of experts have said today is a textbook illustration of the risks of putting all of your eggs in one basket in terms of a service provider – AWS is a giant and millions of businesses rely on it.

And they are right, but the issue is there aren’t many alternatives at the sheer scale provided by AWS.

There are only two main contenders in fact, and they’re both other US giants: Microsoft’s Azure and Google’s Cloud Platform.

Smaller rivals include IBM and the Chinese firm Alibaba. The parent company of the supermarket Lidl launched a European rival called Stackit last year, in direct competition with Amazon.

But AWS remains the dominant player by some margin.

Some argue the UK and Europe urgently needs to build up its own infrastructure and be less reliant on the US for cloud services – while others say it’s too late.

Someone working in government once told me an MP informally proposed creating a UK version of AWS.

“But what’s the point?” came the reply. “We already have AWS, over there.”

Perhaps incidents like today’s highlight why it’s not quite that simple.