Provision a VM with Cloud Image and Cloud-init

Image by Mikes-Photography from Pixabay

The cloud image is a standard release for many of the Linux distributions. Thanks to cloud-init, we can uniformly provision and customize a VM quickly for different flavors of Linux in a standard way.

Take an example of a Ubuntu cloud image with KVM.

1. Get the latest cloud image

Download the current version of 20.04 LTS,

curl -LO http://cloud-images.ubuntu.com/focal/current/focal-server-cloudimg-amd64-disk-kvm.img

2. Create the image disk

Use the base image as a backing image, create a new disk of 100GB

qemu-img create -b focal-server-cloudimg-amd64-disk-kvm.img -F qcow2 -f qcow2 cl-ubuntu.qcow2 100G

Specify the backing image format with “-F” also.

3. Prepare Cloud-init disk

Create the following user data for cloud-init, named as userdata.yaml

#cloud-config
hostname: cl-ubuntu
fqdn: cl-ubuntu
manage_etc_hosts: false
ssh_pwauth: true
disable_root: false
users:
  - default
  - name: ubuntu
    shell: /bin/bash
    sudo: ALL=(ALL) NOPASSWD:ALL
    lock_passwd: false
    ssh-authorized-keys:
      - "content of ssh public key..."