Comment 2 for bug 1439855

Bug 1432490 is related and sounds like it's a user/config error. Nova could parse stderr though and raise a more useful error in this case. I can't find any docs on the max name length for cryptsetup which leads me to believe it's kernel-specific so nova would just have to catch the ProcessExecutionError and parse stderr to see if that's the issue to give a more useful nova exception back.