What is Fastly? Why the CDN outage caused Reddit, Amazon and other websites to go down with 503 errors
2 min read
Many of the world’s largest websites went down on Tuesday morning, including Amazon, Reddit and many major news outlets.
The outage was due to a problem with edge cloud platform Fastly, which supports some of the internet’s biggest sites.
DownDetector reported the likes of Spotify, Twitter, PayPal, Etsy, eBay, Twitch, Pinterest, Shopify, Vimeo, GitHub, Squarespace, Imgur, Tidal, Weightwatchers, Kickstarter and the Government website going down.
The issue started shortly before 11am UK time, and lasted for around an hour. Users were getting 503 “service unavailable” errors when trying to visit these websites, or being presented with largely blank screens.
What is Fastly?
Fastly is a cloud computing services provider that runs a content delivery network (CDN).
A CDN is a geographically distributed network of proxy servers and their data centres designed to speed up loading times for websites, protect them from attacks, and help them deal with increased traffic.
It caches some data from websites as close to the end user as possible – improving performance for the user and limiting the toll on the website’s server. However, if it suffers an issue it can mean the entire website – or in this case several huge sites – going down.
This is a negative of internet infrastructure becoming centralised – a company like Fastly suffering a problem can cause mass outages across some of the world’s most important websites.
What caused today’s outage?
Fastly posted an update to its website at 10.58am, saying it was investigating “potential impact to performance with our CDN services”.
By 11.44am it had identified the issue, and it was fixed shortly before midday.
“Customers may experience increased origin load as global services return,” it said.
Fastly posted on Twitter: “We identified a service configuration that triggered disruptions across our POPs globally and have disabled that configuration.”
The outage was localised to Europe, with the whole of the UK affected.
Similar mass outages have happened in the past. Last year an issue with Cloudflare affected major sites in many US and European cities, while in 2017 Amazon’s AWS went down, causing problems on the East Coast of the US.
