[virt-tools-list] SOLVED: Re: what is virt-viewer intended to be ?

Tue May 16 12:08:51 UTC 2017

> ----- On May 16, 2017, at 12:53 PM, Bernd Lentes
> bernd.lentes at helmholtz-muenchen.de wrote:
> 
> 
>> 
>> Hi guys,
>> 
>> thanks for your quick answer. I have some further questions. I will leave
>> windows and try to connect to libvirt or guest consoles from a linux box.
>> My scenario is that i have a few guests which are controlled by pacemaker in a
>> two node cluster.
>> I'd like to have the ability to connect to the consoles when the guests have
>> problems in booting. This way maybe i can identify the problems.
>> I don't want to open the libvirt port if possible but connect to libvirt/guest
>> consoles using ssh.
>> I managed to connect to the hypervisor using virsh and ssh from a remote linux
>> box.
>> My idea is that i configure in each guest a vnc display with increasing port
>> numbers, starting from 5900, so i can connect to each guest indepently,
>> and to several concurrently.
>> I'd like to bind the vnc display just to the localhost interface because of not
>> exposing this port.
>> I can connect to the hypervisor with the following: virt-viewer -vc
>> qemu+ssh://root@ha-idg-1/system
>> Then i get a list of the running guests (currently only one). I choose it, and
>> then ... nothing happens :-(
>> Virt-viewer says "waiting for display 1...", and i get the following message on
>> my terminal:
>> "(virt-viewer:810): Gtk-WARNING **: Allocating size to VncDisplay 0x10282f0
>> without calling gtk_widget_get_preferred_width/height(). How does the code know
>> the size to allocate? "
>> 
>> This is the output of my shell:
>> 
>> (virt-viewer:8414): virt-viewer-DEBUG: connecting ...
>> (virt-viewer:8414): virt-viewer-DEBUG: Opening connection to libvirt with URI
>> qemu+ssh://root@ha-idg-1/system
>> Opening connection to libvirt with URI qemu+ssh://root@ha-idg-1/system
>> Password:
>> (virt-viewer:8414): virt-viewer-DEBUG: initial connect
>> (virt-viewer:8414): virt-viewer-DEBUG: notebook show status 0x1950200
>> 
>> (virt-viewer:8414): Gtk-WARNING **: Theme directory base/ of theme oxygen has no
>> size field
>> 
>> (virt-viewer:8414): virt-viewer-DEBUG: virt_viewer_app_set_uuid_string: UUID
>> changed to f08c2f32-fe35-137a-0e9d-fa7485d57974
>> (virt-viewer:8414): virt-viewer-DEBUG: notebook show status 0x1950200
>> (virt-viewer:8414): virt-viewer-DEBUG: Guest mausdb_vm is running, determining
>> display
>> Guest mausdb_vm is running, determining display
>> (virt-viewer:8414): virt-viewer-DEBUG: Set connect info:
>> (null),(null),-1,-1,(null),(null),(null),0
>> (virt-viewer:8414): virt-viewer-DEBUG: Guest mausdb_vm has a vnc display
>> Guest mausdb_vm has a vnc display
>> (virt-viewer:8414): virt-viewer-DEBUG: Guest graphics address is 127.0.0.1:5900
>> (virt-viewer:8414): virt-viewer-DEBUG: Set connect info:
>> ha-idg-1,127.0.0.1,5900,-1,ssh,(null),root,0
>> (virt-viewer:8414): virt-viewer-DEBUG: Error operation forbidden: read only
>> access prevents virDomainOpenGraphicsFD
>> (virt-viewer:8414): virt-viewer-DEBUG: After open connection callback fd=-1
>> (virt-viewer:8414): virt-viewer-DEBUG: Opening indirect TCP connection to
>> display at 127.0.0.1:5900
>> Opening indirect TCP connection to display at 127.0.0.1:5900
>> (virt-viewer:8414): virt-viewer-DEBUG: Setting up SSH tunnel via root at ha-idg-1
>> Setting up SSH tunnel via root at ha-idg-1
>> (virt-viewer:8414): virt-viewer-DEBUG: notebook show status 0x1950200
>> (virt-viewer:8414): virt-viewer-DEBUG: reconnect_poll: 0
>> (virt-viewer:8414): virt-viewer-DEBUG: notebook show status 0x1950200
>> (virt-viewer:8414): virt-viewer-DEBUG: Insert display 0 0x1897c60
>> (virt-viewer:8414): virt-viewer-DEBUG: notebook show status 0x1950200
>> Password: (virt-viewer:8414): virt-viewer-DEBUG: Allocated 1024x740
>> (virt-viewer:8414): virt-viewer-DEBUG: Child allocate 1024x640
>> 
>> (virt-viewer:8414): Gtk-WARNING **: Allocating size to VncDisplay 0x1a2a2f0
>> without calling gtk_widget_get_preferred_width/height(). How does the code know
>> the size to allocate?
>> (virt-viewer:8414): virt-viewer-DEBUG: Window closed
>> (virt-viewer:8414): virt-viewer-DEBUG: close vnc=0x1a2a2f0
>> (virt-viewer:8414): virt-viewer-DEBUG: Not removing main window 0 0x187ec60
>> (virt-viewer:8414): virt-viewer-DEBUG: Disconnected
>> (virt-viewer:8414): virt-viewer-DEBUG: close vnc=0x1a2a520
>> (virt-viewer:8414): virt-viewer-DEBUG: notebook show status 0x1950200
>> (virt-viewer:8414): virt-viewer-DEBUG: Guest mausdb_vm display has disconnected,
>> shutting down
>> Guest mausdb_vm display has disconnected, shutting down
>> pc65518:~ #
>> Password:
>> Password:
>> Permission denied (publickey,keyboard-interactive).
>> pc65518:~ # pc65518:~ # pc65518:~ #
>> 
>> 
>> Do i have to provide the desired resolution ? How can i do that ?
>> I tried virt-viewer with -f, but that didn't help.
>> 
>> What means "(virt-viewer:8414): virt-viewer-DEBUG: Error operation forbidden:
>> read only access prevents virDomainOpenGraphicsFD
>> (virt-viewer:8414): virt-viewer-DEBUG: After open connection callback fd=-1" ?
>> 
>> Is my idea basically possible ? Or is it the problem that vnc is just listening
>> on localhost ?
> 
> I tested a bit. I'm able to tunnel with ssh a local port to 127.0.0.1 on a
> remote box.
> So i think that's not the problem.
> 

I found a solution which is fine for me:

- configure each guest with a vnc display listening on localhost, with increasing port numbers, beginning from 5900
- on a linux box with X (which is available for the respective users) creating a ssh tunnel to connect to the vcn display:
  pc65518:~ #  ssh -L 127.0.0.1:5900:127.0.0.1:5900 ha-idg-1
- on the linux box starting vncviewer:
  pc65518:~#  vncviewer 127.0.0.1:5900

- connection is encrypted
- vnc port is not exposed
- several vnc sessions concurrently possible

everything is fine for me.

Bernd

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