pdo allows users to run SSH commands on multiple remote hosts in parallel, or run commands (such as rsync etc.) locally against multiple remote hosts in parallel.
N-stage worm propagated via SSH. It executes commands in a given list of hosts and copies files to them with rsync. The paths for its propagation to the cluster are configurable. It offers a scalable/reliable transport API thanks to its adaptive algorithm
PFARS For Automatic Replication System is mainly used to sync servers in LVS clusters but also has many other uses. It is based on rsync over ssh and has native support for the Debian package system.