Hi again,
I spent some time trying to debug this:
added some printouts and noticed that the virNetSocketDupFD() function is called with cloexec = True, hence triggering the call: fd = fcntl(sock->fd, F_DUPFD_CLOEXEC);
However, running on CentOS 5.5 our glibc version is glibc-2.5-49.el5_5.5, and it seems the F_DUPFD_CLOEXEC flag was not added until glibc2.7 [1]. I then tried to replace that code with:
if (cloexec) {
fd = fcntl(sock->fd, F_DUPFD);
if (fd >= 0)
fcntl(fd, F_SETFD, FD_CLOEXEC);
}
but the results are the same; Unable to copy socket file handle: Invalid argument
I also added some more printouts to find more about the fd:
2012-01-31 11:20:24.093+0000: 10445: error : virNetSocketDupFD:790 : sock->fd: 15, cloexec: 1: Invalid argument
and can at least see that fd 15 is the one complaining. Looking at lsof for the KVM process:
kvm 7456 root 13u 0000 0,8 0 852 anon_inode
kvm 7456 root 14u IPv4 167375 TCP localhost.localdomain:5900 (LISTEN)
kvm 7456 root 15r FIFO 0,7 167376 pipe
kvm 7456 root 16w FIFO 0,7 167376 pipe
kvm 7456 root 17u CHR 10,200 2986 /dev/net/tun
Seems like it fails duplicating a pipe leading back to the same process?
Regards,
Daniel
1) http://stackoverflow.com/questions/1643304/how-to-set-close-on-exec-by-default
On Jan 30, 2012, at 3:14 PM, Daniel Espling wrote:
> Dear all,
>
> we're having two different problems with migrations in libvirt, running as root user on host machines with CentOS release 5.5 (Final), kernel: Linux 2.6.32.24 #3 SMP Fri Oct 29 16:22:02 BST 2010 x86_64 x86_64 x86_64 GNU/Linux
>
> First case:
>
> virsh version
> Compiled against library: libvir 0.9.4
> Using library: libvir 0.9.4
> Using API: QEMU 0.9.4
> Running hypervisor: QEMU 1.0.50
>
> Migrations work well for a basic VM, but if we attach a disk to the usb bus migration is no longer possible and fails with the error message: "error: operation failed: migration job: is not active". This is regardless of if the device is mounted inside the VM or not (debian). Please find more information attached.
>
> If we attach the same (.iso based) disk to the scsi bus instead, migrations work as normal.
>
> ----
>
> To mitigate this problem, we tried upgrading to a more recent libvirt version:
>
> Compiled against library: libvir 0.9.9
> Using library: libvir 0.9.9
> Using API: QEMU 0.9.9
> Running hypervisor: QEMU 1.0.50
>
> When trying to migrate a normal (debian) instance from one host to another using the same domain as in the previous successful case without any devices attached, migration fails with the error message "error: Unable to copy socket file handle: Invalid argument". The libvirt.log only has a similar single-line of information: 2012-01-30 15:44:46.772+0000: 7546: error : virNetSocketDupFD:787 : Unable to copy socket file handle: Invalid argument.
>
> The network configuration used here is the same as we successfully used in the 0.9.4 test case, using static ip's.
>
> Thankful for assistance, not really sure what to try next. :)
>
> Regards,
> Daniel Espling
>
>
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