[libvirt-users] libvirt beginner needs to create and start VMs entirely on command line

Jeff Tchang jeff.tchang at gmail.com
Fri Jul 10 20:15:06 UTC 2015


That's kind of weird. I don't think VNC has anything to do with X really.
Are you able to connect with VNC?
If you are able to establish a connection the first thing you should see is
a login prompt on most distributions (unless the distribution is configure
to start X windows). Maybe there is some key you can press to get a console
window.
Like CTRL-ALT-F1 or F2 or F3.


On Fri, Jul 10, 2015 at 11:37 AM, KARR, DAVID <dk068x at att.com> wrote:

>   This is offtopic, but related to what you’ve told me so far.  I’m
> having some trouble getting the VNC connection to work.  Technically, the
> “connection” is working fine, but the Windows TightVNC Viewer comes up with
> an error dialog saying this:
>
> Xsession: unable to start X session --- no "/home/.../.xsession" file, no
>
> "/home/.../.Xsession" file, no session managers, no window managers, and
> no
>
> terminal emulators found; aborting.
>
>
>
> The ~/.xsession-errors file on the remote box says the same thing (so that
> confirms my port forwarding is working), and I definitely do NOT have a
> ~/.xsession file, so the error message is definitely accurate.  I obviously
> need to get a .xsession file, but I’m not sure if the absence of that file
> implies something more “high-level”.  I’m vaguely familiar with what goes
> into .xsession, although I haven’t worked with X11 for ~25 years or so.
>
>
>
> *From:* Jeff Tchang [mailto:jeff.tchang at gmail.com]
> *Sent:* Thursday, July 09, 2015 1:53 PM
>
> *To:* KARR, DAVID
> *Cc:* libvirt-users at redhat.com
> *Subject:* Re: [libvirt-users] libvirt beginner needs to create and start
> VMs entirely on command line
>
>
>
> To see the boot console you need to have a VNC client and connect to it
> once it is up.
>
>
>
> For Mac OS I use the "Screen Sharing" application which can connect to VNC
> natively.
>
> For Windows you can use something like tightvnc.
>
>
>
> For SSH you need to make sure it is listening on the port.
>
>
>
> --network is used to specify a libvirt network I believe.
>
>
>
> On my example box it is in /var/lib/libvirt/network/default.xml
>
>
>
> <!--
>
> WARNING: THIS IS AN AUTO-GENERATED FILE. CHANGES TO IT ARE LIKELY TO BE
>
> OVERWRITTEN AND LOST. Changes to this xml configuration should be made
> using:
>
>   virsh net-edit default
>
> or other application using the libvirt API.
>
> -->
>
>
>
> <networkstatus>
>
>   <class_id bitmap='0-2'/>
>
>   <floor sum='0'/>
>
>   <network>
>
>     <name>default</name>
>
>     <uuid>*****</uuid>
>
>     <forward mode='nat'>
>
>       <nat>
>
>         <port start='1024' end='65535'/>
>
>       </nat>
>
>     </forward>
>
>     <bridge name='virbr0' stp='on' delay='0'/>
>
>     <mac address='****'/>
>
>     <ip address='192.168.5.1' netmask='255.255.255.0'>
>
>       <dhcp>
>
>         <range start='192.168.5.100' end='192.168.5.254'/>
>
>         <host mac='aa:bb:cc:dd:dd:dd' name='example-reserved'
> ip='192.168.5.10'/>
>
>       </dhcp>
>
>     </ip>
>
>   </network>
>
> </networkstatus>
>
>
>
> So basically you do --network default and then make sure the VM is
> configured to do a DHCP out and it will get an address.
>
>
>
> virsh net-edit default is the command you want to run.
>
> There is also a command to view the networks that libvirt has.
>
>
>
> On Thu, Jul 9, 2015 at 11:48 AM, KARR, DAVID <dk068x at att.com> wrote:
>
>  Thanks for replying.  Good info so far.
>
>
>
> After I start the VM, I’m going to need to see the boot console, and I’ll
> need to ssh into it with a hostname or IP.  What are some required steps
> for those needs?
>
>
>
> This VM is going to need to access a few associated networks.  I can see
> that the “—networks” option is part of the interface for configuring
> this.  What are some things I’ll have to do for this?
>
>
>
> *From:* Jeff Tchang [mailto:jeff.tchang at gmail.com]
> *Sent:* Thursday, July 09, 2015 11:21 AM
> *To:* KARR, DAVID
> *Cc:* libvirt-users at redhat.com
> *Subject:* Re: [libvirt-users] libvirt beginner needs to create and start
> VMs entirely on command line
>
>
>
> I actually find I do almost all my VM management inside the virsh command.
>
> If the VM appears to exist inside virsh but is in a shut off state then
> you should try to start it.
>
>
>
> VNC can also be SSH port forwarded (which I have done before).
>
>
>
> Not sure if this will help but this is the command I use to create VMs:
>
>
>
> virt-install \
>
>   --name example \
>
>   --vcpus=4 \
>
>   --disk /data/example,size=80 \
>
>   --ram 2048 \
>
>   --graphics vnc,password=**********,listen=0.0.0.0,port=15916 \
>
>   --accelerate \
>
>   --cdrom /var/kvm/ubuntu-14.04.1-server-amd64-autoinstall.iso \
>
>   --os-type=linux \
>
>   --noautoconsole \
>
>   --network network=default \
>
>   --boot cdrom,fd,hd,network,menu=off
>
>
>
> I also edit the XML file sometimes. Notice I have the autoinstall iso.
> Basically I went through and created a ks.cfg file after extracting the ISO
> file to a directory. Then I ran a command like this:
>
> mkisofs -D -r -V "auto install" -cache-inodes -J -l -b
> isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size
> 4 -boot-info-table -o /var/kvm/ubuntu-14.04.1-server-amd64-autoinstall.iso
> /root/serveriso
>
>
>
>
>
> On Thu, Jul 9, 2015 at 10:57 AM, KARR, DAVID <dk068x at att.com> wrote:
>
> I'm a beginner to libvirt and creating VMs, for that matter.  I have a set
> of specifications for VMs I need to create and log into, but I have to
> create them on an Ubuntu box that I only have ssh access to.  I won't have
> desktop GUI access, although I do have dynamic port forwarding, so I can
> access a browser GUI from my desktop.
>
> Reading through the libvirt info, I see numerous mentions about using VNC
> to do additional work, but I won't be able to use VNC (not allowed within
> our firewall).
>
> I could use some advice on how to move forward with this.  I've started at
> https://help.ubuntu.com/lts/serverguide/libvirt.html for initial
> information.
>
> I managed to create a disk image for my first VM, and I believe I created
> the first VM using an ISO (based on CentOS, I believe), but I'll probably
> have to rebuild that, because I think I have to configure networks on the
> VM, which I didn't do on initial creation.  I was confused by the initial
> results from "virt-install", because it seemed to hang after a second or
> two (I posted this SO question about this:
> http://stackoverflow.com/questions/31302871/trouble-using-virt-install-on-ubuntu-to-create-vm-just-hangs-after-displaying
> ).  The reply from this makes it seem like it was trying to present a GUI
> for next steps, but I of course never saw that.  The VM appears to exist,
> but in a "shut off" state.
>
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