How Leap Year Brought Down Windows Azure Cloud Services
So finally, its the Leap year that brought down the Windows Azure Cloud services. The root cause behind the Windows Azure Outage was found to be a simple Leap day bug. Read more on Windows Azure blog here.
When the GA creates the transfer certificate, it gives it a one year validity range. It uses midnight UST of the current day as the valid-from date and one year from that date as thevalid-to date. The leap day bug is that the GA calculated the valid-to date by simply taking the current date and adding one to its year. That meant that any GA that tried to create a transfer certificate on leap day set a valid-to date of February 29, 2013, an invalid date that caused the certificate creation to fail.
Source : Windows Azure Blog
Isn't it a brighter spot of the whole issue that Microsoft got 4 years to fix the root cause of the issue :-))