This document has been moved to the Hawk source tree, so you can read it at https://github.com/ClusterLabs/hawk/blob/master/doc/design-old.txt

Note that as of 2013-08-15 it is rather outdated (e.g.: it still refers to rails 2, and claims that "explore failure scenarios" isn't implemented yet, but that functionality went into hawk 0.5.x).

For a more general overview, please see Hawk.