Hi, As the subject line indicates, when I'm calling virDomainCreate() to start a defined domain, and that command fails because the domain is already running at that point, virGetLastError() will return NULL, instead of a proper pointer to an error code. Libvirt will, however, print an error to the console: libvir: QEMU error : Requested operation is not valid: domain is already running

This looks like a bug to me, and I'm fairly certain that earlier version would return an error code of VIR_ERR_OPERATION_INVALID at that point. Or maybe that was just virDomainDestroy(), and I'm just blindly assuming that virDomainCreate() will work analogously... Anyway, no error code is bad, because I can't tell what happened.

On 02/22/2012 11:16 AM, Eric Blake wrote: > On 02/22/2012 07:06 AM, Guido Winkelmann wrote: >> Hi, >> >> As the subject line indicates, when I'm calling virDomainCreate() to >> start a defined domain, and that command fails because the domain is >> already running at that point, virGetLastError() will return NULL, >> instead of a proper pointer to an error code. >> Libvirt will, however, print an error to the console: >> >> libvir: QEMU error : Requested operation is not valid: domain is already >> running > > Any return of NULL without a last error set is a bug. I'm trying to > chase this down, and hope to have a patch soon. I can't reproduce this. I tested on libvirt 0.9.10, starting with an inactive domain 'dom' and using 'virsh dumpxml dom > dom.xml; virsh create dom.xml; virsh create dom.xml', and the second create gave me a proper error message of "Requested operation is not valid: domain is already active as 'dom'".

Can you post the code snippet you are using to get this situation?

Could it be that you have a different name and/or UUID in the xml from the domain already running (my test obviously reused the same name and uuid from what is already running).

Am Donnerstag, 23. Februar 2012, 13:40:03 I wrote: > Am Mittwoch, 22. Februar 2012, 11:26:50 schrieb Eric Blake: > > Can you post the code snippet you are using to get this situation? > > Unfortunately, the problem occurs inside a fairly large, and unfortunately > not Open-Source, C++ program. I will try to reduce it to a minimal > testcase > as soon as I get around to it. Okay, I wrote a minimal testcase that does just the operations that lead to the problem, only to find out that this won't reproduce the bug either :-\ That means either I'm inadvertently triggering some rare corner case here who knows where in my code, or the bug is really in my code. I don't think it's the latter, though, because the relevant part of my code looks like this: if(virDomainCreate(vserver.get_virdomain().get()) != 0) { // TODO clean up pointer virErrorPtr error = virGetLastError(); if(error != 0) { syslog(LOG_ERR, "Could not start vserver, error code: %d", error->code); // VIR_ERR_OPERATION_INVALID means the vm was already in a started state if(error->code != VIR_ERR_OPERATION_INVALID) throw std::runtime_error("Could not start vserver"); } else { syslog(LOG_ERR, "Could not start vserver, no error code from libvirt"); throw std::runtime_error("Could not start vserver, no error code from libvirt"); } } There's nothing in there between calling virDomainCreate() and virGetLastError(). There are no other threads, either. Anyway, I've fired up gdb now to see if I can find out where the error object gets lost.