I've configured the jclouds plugin to launch VM's on EC2. The instances simply get the name I've specified, and don't get any random suffix as I've been told it should.
I don't know if it's related, but even though I allowed two instances to be started, only one was ever used. Occasionally, two would be started, but only one ever appeared in Jenkins. Maybe it's due to the names not being unique.
What information can I provide?