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

Fri Jul 10 21:12:23 UTC 2015

I would love to ssh into it.  Running “virsh list –all” says that my VM is running, but is the VM name the hostname?  I tried sshing to that, but it says it can’t resolve the hostname.

From: Jeff Tchang [mailto:jeff.tchang at gmail.com]
Sent: Friday, July 10, 2015 2:03 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

Try some of these combinations:
http://www.howtogeek.com/119293/4-ways-to-recover-from-a-crashed-or-frozen-x-server-on-linux/

The good thing is your vm is up and running. You should try SSHing into it if that works.

On Fri, Jul 10, 2015 at 1:37 PM, KARR, DAVID <dk068x at att.com<mailto:dk068x at att.com>> wrote:
I’m confused. You’re asking if I’m able to connect with VNC in response to my comment that I’m unable to connect with VNC?

What I see when I open the viewer on the port is a window titled “<username> X desktop”, with a grey background, an “X” cursor, and an error dialog (with an “okay” prompt) saying what I described before.

Ctrl-Alt-F1 and similar keys do nothing.

From: Jeff Tchang [mailto:jeff.tchang at gmail.com<mailto:jeff.tchang at gmail.com>]
Sent: Friday, July 10, 2015 1:15 PM

To: KARR, DAVID
Cc: libvirt-users at redhat.com<mailto:libvirt-users at redhat.com>
Subject: Re: [libvirt-users] libvirt beginner needs to create and start VMs entirely on command line

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<mailto: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<mailto:jeff.tchang at gmail.com>]
Sent: Thursday, July 09, 2015 1:53 PM

To: KARR, DAVID
Cc: libvirt-users at redhat.com<mailto: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<mailto: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<mailto:jeff.tchang at gmail.com>]
Sent: Thursday, July 09, 2015 11:21 AM
To: KARR, DAVID
Cc: libvirt-users at redhat.com<mailto: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<http://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<mailto: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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