[libvirt] [vdsm] non-TLS spice connections

Dan Kenigsberg danken at redhat.com
Tue Feb 21 16:09:06 UTC 2012

On Tue, Feb 21, 2012 at 04:53:24PM +0100, Christophe Fergeau wrote:
> Hey,
> I recently setup ovirt/vdsm on one of my boxes. For some reason spice TLS
> was disabled through spice_tls = no in /etc/libvirt/qemu.conf.
> Then I created a VM, started it, and had troubles connecting to it with
> spicec. After investigating (thanks djasa), I realized that qemu was
> started with some encrypted SPICE channels but with no TLS port configured,
> which explained why I couldn't connect.
> https://bugzilla.redhat.com/show_bug.cgi?id=790436 was filed against
> libvirt about this, but now we are wondering how to best fix things in
> libvirt.
> What is currently happening is that libvirt doesn't warn when a domain has
> <channel name='main' mode='secure'/> with spice_tls = no in qemu.conf, and
> it adds the corresponding tls-channel=main to qemu command-line, but
> doesn't set a TLS port (if one is set it's silently ignored).
> There are at least two ways of solving this problem in libvirt:
> * either the current behaviour is kept, but "tls-channel=main" is not
>   added to qemu command line when spice-tls is disabled. The drawback of
>   this is that some security options that have been explicitly set in the
>   domain XML are silently ignored
> * or the current behaviour is changed, and in this situation (SPICE secure
>   channels in the XML, but TLS disabled in qemu.conf), libvirt errors out,
>   which would change the current behaviour.
> This has been discussed on the libvirt mailing list (cc'ed) in this thread:
> https://www.redhat.com/archives/libvir-list/2012-February/msg00656.html
> Before making a decision, we were wondering what behaviour oVirt
> would expect in this case (error or silently ignoring the secure channels),
> and if a setup with spice_tls = no in /etc/libvirt/qemu.conf is something
> widely deployed that you have to support, or if it's more of an
> experimental feature at this point.
> Thanks for any input you can give on this matter,
> Christophe

Please note Bug 788092 - VDSM: Disable vdsm's ssl'ability influence
spice ssl'ability and prevent VM from starting

Could it be that you have ssl=false in your vdsm.conf?

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