There is some information about how to use John the Ripper with a MOSIX cluster, but unfortunately all of them seem to describe its usage with wordlists.
The basic-idea is to split John in 2 parts: 'word-generator' and 'comparer' (this is the de-facto standard for using John with MOSIX).
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./john -session:test.rec -incremental:all -stdout > wooord
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'wooord' is a FIFO pipe (#: mknod wooord p) which will be read by the comparer-processes.
Read more about this at http://itsecurity.mq.edu.au/chaos/howto/