[libvirt] virsh migrate: sometimes command line cannot exit until manually press "ENTER" key

[Shivaprasad bhat]

On Thu, Aug 7, 2014 at 11:02 AM, Chun Yan Liu <cyliu at suse.com> wrote:
> Hi, List,
>
> Do you meet the same problem? Host is kvm, doing: (e.g.)
> #virsh migrate sles11 qemu+ssh://147.2.207.55/system --live --unsafe
> password:
> Sometimes, VM is already running on the target host and disappears
> from source host, but the command line still hangs there, if pressing
> "ENTER", it will exit.
>
> I debugged the code, but found the result is weird. The code hangs at
> tools/virsh-domain.c -> cmdMigrate ->vshWatchJob->poll():
> poll() is trying to select pipe_fd, which is used to receive message from
> doMigrate thread. In debugging, found that doMigrate finishes and at
> the end it  does call safewrite() to write the retval ('0' or '1') to pipe_fd,
> and the write is completed. But cmdMigrate poll() cannot get the event.
> Then after pressing "ENTER" key, poll() can get the event and select
> pipe_fd, then command line can exit.
>
> Any ideas about the possible reason?

It is because, the authentication thread is independently waiting for the
password on virsh. I see that the virWatchJob interferes with authentication
thread and the password is never taken successfully. The virWatchJob
probably needs to wait till the authentication thread completes taking the
password after which it should start watching the job. Moreover, I see
that --p2p
migration doesnt work at all when auto login is not configured.

>
> Thanks,
> Chunyan
>
>
> --
> libvir-list mailing list
> libvir-list at redhat.com
> https://www.redhat.com/mailman/listinfo/libvir-list

Thanks,
Shiva