Yesterday, websites such as Amazon, Reddit, Spotify, PayPal, Ebay, Twitch and Pinterest went offline due to a major outage of a service called Fastly. 503 errors were sprouting up all over the web, revealing an unsuspected reliance on this largely misunderstood cloud computing service.
In the middle of the day in Spain, Fastly's status update page reported an error, stating, "we are currently investigating the potential impact to the performance of our CDN [content delivery network] services." Soon after, alerts appeared on Twitter that major news outlets including Le Monde, the BBC, CNN and The New York Times were offline. Twitter itself was still working, but the server hosting its emojis went down.
It turned out to be a massive outage that brought much of the internet to its knees. People around the world were getting "Error: 503" messages when trying to access sites, including vital services.
Nearly an hour later, Fastly said the issue has been identified and a fix is being rolled out.
What is Fastly?
Fastly is a cloud computing service provider that has been around since 2011 and is headquartered in San Francisco (USA). In 2017, it launched an edge cloud computing platform designed to bring websites closer to the people who use them. Concretely, this means that if you access a website hosted in another country, it will store part of that website closer to you, so there is no need to waste bandwidth fetching all content of this website away. This makes web pages load faster and optimizes images, videos, and other resource-intensive content to display quickly.
This intermediate position of the Fastly infrastructure between the back-end web servers and the front-end Internet means that any failure on its part can lead to the unavailability of entire websites. It also means that errors do not affect all regions in the same way and at the same time.
When a website shows a 503 error, it means that the server hosting it is not ready to process the request. This type of error usually occurs when a server is down for maintenance or when a website is overloaded, for example if too many people try to access it at the same time.
What happened at Fastly?
We just know that yesterday's outage was caused by a "service configuration", but nothing more. Until Fastly conducts a thorough investigation, it will be difficult to determine the cause of this failure. It is important to emphasize that this is not necessarily a malicious attack. There are many technical reasons why a CDN can go down and cyberattacks are just one of them.
Image : quapan CC BY 2.0
