Jenkins and Maven SCP Error: reject HostKey

We lost one of our internal build machines recently (that was a sad day), and so we've been rebuilding our Jenkins environment from the ground up. We use scp access for our distributionManagement control in Maven. Because of this, Jenkins broke on our first build with a whole lot of output saying "The host was not known and was not accepted by the configuration", which narrowed down to this exception:

Caused by: com.jcraft.jsch.JSchException: reject HostKey

Grails Infinitely Prompts During Jenkins Build

I've mentioned before how I'm using CloudBees RUN@cloud as my hosting solution for Scripty Note... well right alongside that I'm using their DEV@cloud Jenkins CI environment. I have a decent amount of experience with Continuous Integration environments (Hudson, Jenkins... even Cruise Control way back when). I even use and maintain a Jenkins build machine every day at MagnetStreet. So I definitely know my way around Jenkins.

That said, I was recently at a loss when I added the MySQL Connector/J grails plugin to the Scripty Note project. Everything worked great on my own machine, but when Jenkins picked it up, I was in for some excitement. The build started at about 10pm that night (which I was not monitoring) and when I checked build status the next morning, lo and behold, all of my DEV@cloud build minutes had been used up and I had received an email from someone at CloudBees saying they had stopped my build when they noticed my EBS volume had filled up because of my build log. The build had been running in an infinite loop, prompting in the log:

"Overwrite existing DataSource.groovy? (y, Y, n, N)"