Eucalyptus: running a private cloud on Ubuntu

Posted May 2, 2009 0:11 UTC (Sat) by giraffedata (guest, #1954)
Parent article: Eucalyptus: running a private cloud on Ubuntu

They are charged for each hour the virtual machine runs

I always find this description misleading. It's really, "charged for each hour the virtual machine exists." There's no such thing in EC2 as a virtual machine that is not running. If you don't want to pay the full time charge, you have to destroy your virtual machine when you don't need it and build another one like it later on. Also, because it's meant for applications that can work that way, various system glitches can cause your virtual machine to vaporize, and you're expected to build a replacement when that happens. This is in contrast with other cloud architectures where the virtual machine is expected to be perpetual.

Incidentally, Amazon literature often describes the pricing scheme as "you pay for only what you use," which is similarly misleading. You pay for every hour a virtual machine exists, regardless of how much real CPU time and memory it uses.