Comment 2 for bug 2056195

The error message is caused by the users doing something wrongly. This is not a bug in Nova.

But I think the users should get the message that they are doing something wrongly, and therefore Nova should throw the users a 409 client error (conflict) instead of a 500 server error (internal server error). This I regard as a bug in Nova.

The way it is implemented currently is that because the users get the 500 error, so they think that something is wrong on the server side. The users need to know that they are doing something wrong.