I got a custom image for a server in Rackspace, it takes more than 10 minutes (600 seconds) to build because it's compression (I guess), so JClouds Plugin deletes it after 10 minutes and tries to build another server, making that the job never completes properly (it just sits on the queue), here is what I get from the Jenkins' logs

may 09, 2014 11:43:40 PM Grave org.jclouds.logging.jdk.JDKLogger logError
<< problem customizing node(DFW/4acc0220-af9e-4e23-bd16-5cafcc669ed8):
java.lang.IllegalStateException: node(DFW/4acc0220-af9e-4e23-bd16-5cafcc669ed8) didn't achieve the status running; aborting after 600 seconds with final status: PENDING
at org.jclouds.compute.functions.PollNodeRunning.apply(PollNodeRunning.java:72)
at org.jclouds.compute.functions.PollNodeRunning.apply(PollNodeRunning.java:45)
at org.jclouds.compute.strategy.CustomizeNodeAndAddToGoodMapOrPutExceptionIntoBadMap.call(CustomizeNodeAndAddToGoodMapOrPutExceptionIntoBadMap.java:121)
at org.jclouds.compute.strategy.CustomizeNodeAndAddToGoodMapOrPutExceptionIntoBadMap.apply(CustomizeNodeAndAddToGoodMapOrPutExceptionIntoBadMap.java:146)
at org.jclouds.compute.strategy.CustomizeNodeAndAddToGoodMapOrPutExceptionIntoBadMap.apply(CustomizeNodeAndAddToGoodMapOrPutExceptionIntoBadMap.java:53)
at shaded.com.google.common.util.concurrent.Futures$1.apply(Futures.java:711)
at shaded.com.google.common.util.concurrent.Futures$ChainingListenableFuture.run(Futures.java:849)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:744)

(please see the attached file for details)

I suggest adding a button in the configuration that starts building a server with the objective of making an approximate timing of how much time it takes to build a server slave before using it for the image being added, to avoid hard coding the timeout times and making it more flexible.