If you're running the Hudson continuous integration server, you may want to run/build/test on multiple slave servers.
To do this, log into the Hudson web interface and go to Hudson > nodes. Configure your new slave server by adding the name, description, remote file system root for Hudson (ex. /var/hudson), and the job launch method.
For job launch method, ssh is fine for Linux based systems. Click the 'Advanced' button to enter ssh details (ex. keys).
Now, when you start up the slave, you may see this in your slave ssh log under the Hudson console output :
* Could not copy slave.jar to slave
The solution to this problem is to ensure the remote file system root (ex. /var/hudson) is writable by the ssh user you entered to make the ssh connection.