Bookies are individual BookKeeper servers. You can run an ensemble of bookies locally on a single machine using the localbookie command of the bookkeeper CLI tool and specifying the number of bookies you’d like to include in the ensemble.

This would start up an ensemble with 10 bookies:

\$ bin/bookkeeper localbookie 10

When you start up an ensemble using localbookie, all bookies run in a single JVM process.