An interesting read, if you are curious about arm systems as linux clusters. Apache-Mesos running on Raspberry Pi.
http://ispyker.blogspot.com/2016/05/services-with-netflix-titus-and.html I find this sort of post, very encouraging, as my goals are for clusters on embedded arm boards that run gentoo. Very similar, inexpensive and attractive for the entire Gentoo community. enjoy, James