[CentOS] Secret incantations for virt-viewer?

[Bill Gee]

On Tuesday, December 30, 2014 13:01:57 SilverTip257 wrote:
> On Tue, Dec 30, 2014 at 9:58 AM, Marcelo Roccasalva <
> 
> marcelo-centos at irrigacion.gov.ar> wrote:
> > On Tue, Dec 30, 2014 at 11:46 AM, Bill Gee <bgee at campercaver.net> wrote:
> > > Hello everyone -
> > > 
> > > I am trying to use virt-viewer to connect to KVM virtual machines
> > > running
> > > on a
> > > CentOS7 host.  It works great when running directly on the host, but I
> > 
> > have
> > 
> > > not been able to figure out the magic connection string to make it work
> > > from
> > > another computer.
> > 
> > virt-viewer connects to a VNC console, which is listening only on
> > localhost. You need to modify the VNC console on the VM to access throu
> > the
> > network.
> 
> As Marcelo points out, by default QEMU listens on localhost for VNC
> consoles.
> If you grep vnc out of the qemu.conf, you'll get hints at a bunch of
> different options.
> More than likely you want the vnc_listen config parameter.
> 
> ~]# grep vnc /etc/libvirt/qemu.conf
> vnc_listen = "X.X.X.X"
> # over vnc_listen.
> #vnc_auto_unix_socket = 1
> #vnc_tls = 1
> # default it to keep them in /etc/pki/libvirt-vnc. This directory
> #vnc_tls_x509_cert_dir = "/etc/pki/libvirt-vnc"
> # certificate signed by the CA in /etc/pki/libvirt-vnc/ca-cert.pem
> #vnc_tls_x509_verify = 1
> #vnc_password = "XYZ12345"
> #vnc_sasl = 1
> #vnc_sasl_dir = "/some/directory/sasl2"
> #vnc_allow_host_audio = 0
> # result into negative vnc display number.
> 
> I suspect (although I have not tested it) that the method Patrick suggested
> tunnels through SSH.
> 
> [ Personally I don't use virt-viewer often and instead use virsh CLI along
> with a VNC client if necessary. ]

Hi Mike -

Thanks!  I changed the qemu.conf file to listen on 0.0.0.0.  That works - I can 
connect to the virtual machines using a VNC client.

The problem with VNC is that the port number assigned to a particular VM 
depends on the order in which it is started.  There is no command-line option 
for VNC that will attach to a VM by name ...  only by display number or port 
number.

With virt-viewer I can name the domain on the command line.  It is unambiguous 
- There is no doubt about which VM it will connect to.

I found where the VNC port can be fixed in the XML file that defines each VM.  
However, it is a manual process.  I have not found a way to set it using 
virsh.  

I found where virsh can report the VNC port number used by a domain.  However, 
the computers from where I am running VNC client do not have virsh installed.

Somewhere in all this experimenting I have managed to break virt-viewer again.  
It was working, but no more.  Argh!  Good thing this is all happening on test 
computers!

Bill Gee