On the one hand I am very impressed they managed this, but on the other, it does seem very sledgehammer/nut-esque. Even without virtual IPs, it seems a little silly that their customers weren't running N+1 redundant instances that could be taken out, upgraded and then swapped without disrupting normal operations.
Again, very impressive as an academic exercise, especially considering the given script isn't actually that complicated, but wow, they had some serious guts running this in production!
Again, very impressive as an academic exercise, especially considering the given script isn't actually that complicated, but wow, they had some serious guts running this in production!