====== libvirt ======

===== Creating a VM =====

==== Creating an KVM VM ====

  virt-install
  --name=<VM name>
  --ram=<memory in MB>
  --location=http://ftp.nz.debian.org/debian/dists/<version>/main/installer-amd64/
  --os-type=linux
  --os-variant=debiansqueeze
  --disk=/img/<vm name>.img,device=disk,bus=virtio,size=<disk size GB>,sparse=true,format=raw

==== Creating an LXC VM ====

  * Capped resources at 512mb of ram and 2 cpus

  cd /img
  mkdir <vmname>
  sudo debootstrap wheezy <vmname> http://mirror.byte.net.nz/debian/
  sudo virt-install --connect lxc:/// --name cubert --ram 512 --vcpu 2 --filesystem /img/cubert/,/ --noautoconsole -w network=vm

  virt-install \
  --connect lxc:///
  --name httpd_guest
  --ram 512
  --vcpus 2
==== Existing KVM image ====

  virt-install
  --name <VM name>
  --ram <memory>
  --disk path=/img/<VM name>.img
  --import --noautoconsole --force

==== Other Useful Options ====

  * Create VM with a bridge attached to eth0 
<code>--network=bridge=eth0,model=virtio</code>

  * Run install over console

<code>--extra-args=console=ttyS0,115200</code>

  * Installing to an LVM Pool instead. Replace disk line with this one. You'll end up with a volume called <vmname>.img

<code>--disk pool=<pool name>,size=<size in GB>,bus=virtio,cache=none</code>

  * If you want a specific name you'll need to create the volume manually first.

<code>virsh vol-create-as <pool name> <volume name> <size></code>

And then use this line to specify it.

<code>--disk vol=<poolname>/<volume name>,bus=virtio,cache=none</code>

===== Open Serial Console to VM =====

  virsh console <VM name>

===== Enable Kernel output over serial =====

On the VM edit /etc/default/grub and update  GRUB_CMDLINE_LINUX

  GRUB_CMDLINE_LINUX="text console=tty0 console=ttyS0,115200n8"
  
Finally run update-grub as root.