Configuring a libvirt domain with a static IP address via cloud-init local datasource

README libvirt cloud-init with static networking.md

Here is how to create a cloud-init disk image and OS disk image suitable for configuring into a libvirt domain file.

In my case I am naming my domain (a.k.a. virtual machine or VM) xenial with a static IP address of 192.168.0.101. The filenames "network-config" and "user-data" files are arbitrary, so they can be named with a prefix for the domain, etc.

First, get the cloud image and convert into QCOW2 format:

qemu-img convert -O qcow2 xenial-server-cloudimg-amd64-disk1.img xenial-server-cloudimg-amd64-disk1.qcow2

and extend the image size, which will become the root volume:

qemu-img resize xenial-server-cloudimg-amd64-disk1.qcow2 +8G

QCOW is a copy-on-write, differential image structure, so create an image relative to the base distribution image:

qemu-img create -f qcow2 -b xenial-server-cloudimg-amd64-disk1.qcow2 xenial.qcow2

Create the cloud-init datasource (DS) image:

cloud-localds -N network-config.yml xenial-user-data.img user-data.yml

Place all of those images in /var/lib/libvirt/images and create the domain:

virsh create domain.xml

Now you can attach to the console of the domain and log in with the pass configured in user-data:

virsh console xenial

domain.xml

<domain type='kvm'>
    <name>xenial</name>
    <memory>1048576</memory>
    <os>
        <type>hvm</type>
        <boot dev="hd" />
    </os>
    <features>
        <acpi/>
    </features>
    <vcpu>1</vcpu>
    <devices>
        <interface type='bridge'>
            <source bridge='br0'/>
            <model type='virtio'/>
        </interface>
        <disk type='file' device='disk'>
            <driver type='qcow2' cache='none'/>
            <source file='/var/lib/libvirt/images/xenial.qcow2'/>
            <target dev='vda' bus='virtio'/>
        </disk>
        <disk type='file' device='disk'>
            <source file='/var/lib/libvirt/images/xenial-user-data.img'/>
            <target dev='vdb' bus='virtio'/>
        </disk>
        <console type="pty">
           <target type="serial" port="1"/>
        </console>
    </devices>
</domain>

etc-network-interfaces

# This section needs to go into the /etc/network/interfaces on the
# host machine. This section replaces what you would have had for eno1
# or whatever your primary physical ethernet device is named.

auto br0
iface br0 inet static
  address 192.168.0.100/24
  gateway 192.168.0.1
  dns-nameservers x.x.x.x x.x.x.x
  bridge_ports eno1
  bridge_maxwait 0

network-config.yml

version: 1
config:
  - type: nameserver
    address:
      - x.x.x.x
      - x.x.x.x
  - type: physical
    name: ens2
    subnets:
     - control: auto
       type: static
       address: 192.168.0.101/24
       gateway: 192.168.0.1

user-data.yml

#cloud-config

password: passw0rd
chpasswd:
  expire: false
ssh_pwauth: no
ssh_authorized_keys:
  - ssh-rsa ...yours goes here...

Thank you very much!