Case: we have a IPv6-only network in the openstack.

When launching VM in that network openstack gives only IPv6 address, but JClouds ignores that due to a lack of support – see https://issues.apache.org/jira/browse/JCLOUDS-748.

This makes NodeMetadata have 0 (zero) adresses and causes following error:
%%
java.util.concurrent.ExecutionException: java.lang.ArrayIndexOutOfBoundsException: 0
at java.util.concurrent.FutureTask.report(FutureTask.java:122)
at java.util.concurrent.FutureTask.get(FutureTask.java:188)
at jenkins.plugins.jclouds.compute.JCloudsCloud$2.call(JCloudsCloud.java:221)
at jenkins.plugins.jclouds.compute.JCloudsCloud$2.call(JCloudsCloud.java:201)
at jenkins.util.ContextResettingExecutorService$2.call(ContextResettingExecutorService.java:46)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:744)
Caused by: java.lang.ArrayIndexOutOfBoundsException: 0
at jenkins.plugins.jclouds.compute.JCloudsLauncher.connectToSsh(JCloudsLauncher.java:178)
at jenkins.plugins.jclouds.compute.JCloudsLauncher.launch(JCloudsLauncher.java:53)
at hudson.slaves.SlaveComputer$1.call(SlaveComputer.java:232)
... 5 more
%%

That ignores plugin's cleanup mechanisms (if any) and causes bloating of the cloud with ill-functional slaves.