The last time a leap second was added, it caused issues with a number of servers running Linux due to a livelock. [0] This had an effect on EC2 [1] and apparently other pieces of software [2] as well.
Nice to see Amazon being proactive about the forthcoming change. Time is just a prime example of one of those things that seems superficially simple, but turns out to be deviously complicated. (If you ever want to bore non-technical types to death at a party, just start talking about the history of time. Bonus points for mentioning the proleptic Gregorian calendar in context.)
I don't think the leap second bug had any effect on EC2 itself; the only reason EC2 was ever blamed is that many of the sites which had issues happened to be hosted on EC2.
Nice to see Amazon being proactive about the forthcoming change. Time is just a prime example of one of those things that seems superficially simple, but turns out to be deviously complicated. (If you ever want to bore non-technical types to death at a party, just start talking about the history of time. Bonus points for mentioning the proleptic Gregorian calendar in context.)
0. http://serverfault.com/questions/403732/anyone-else-experien...
1. http://www.techspot.com/news/49229-leap-second-bug-amazon-ec...
2. http://www.wired.com/2012/07/leap-second-bug-wreaks-havoc-wi...