Cloud-Init Support

Preparing Cloud-Init Templates

The first step is to prepare your VM. You can use any VM. Simply install the Cloud-Init packages inside the VM that you want to prepare. On Debian/Ubuntu-based systems this is as simple as:

apt-get install cloud-init

Already many distributions provide ready-to-use Cloud-Init images (provided as .qcow2 files), so alternatively you can simply download and import such images. For the following example, we will use the cloud image provided by Ubuntu at https://cloud-images.ubuntu.com

download the image

wget https://cloud-images.ubuntu.com/bionic/current/bionic-server-cloudimg-amd64.img

Create a new VM using Proxmox:

qm create 9000 --memory 2048 --net0 virtio,bridge=vmbr0

Import the downloaded disk to local-lvm storage:

qm importdisk 9000 bionic-server-cloudimg-amd64.img local-lvm

Attach the new disk to the VM as a SCSI drive:

qm set 9000 --scsihw virtio-scsi-pci --scsi0 local-lvm:vm-9000-disk-1

Note: Ubuntu Cloud-Init images require the virtio-scsi-pci controller type for SCSI drives.

The next step is to configure a CD-ROM drive, which will be used to pass the Cloud-Init data to the VM.

qm set 9000 --ide2 local-lvm:cloudinit

To enable direct boot from the Cloud-Init image and improve booting speed, set the bootdisk parameter to scsi0 and restrict the BIOS to boot from the disk only:

qm set 9000 --boot c --bootdisk scsi0

Configure a serial console as a display, which is often required for many Cloud-Init images:

qm set 9000 --serial0 socket --vga serial0

Convert the VM into a template for faster deployment of linked clones:

qm template 9000

Image Cleaning with virt-sysprep

To clean the VM image before cloning, you can use the virt-sysprep command on the VM host
root@pve:~# locate –i *base-9001*

Run virt-sysprep on the VM disk to clean it:

 virt-sysprep -a /dev/pve/vm-9004-disk-0 \
  --update \
  --delete '/var/log' \
  --delete '/var/cache/apt/archives' \
  --delete '/tmp' \
  --delete '/root/.bash_history' \
  --delete '/etc/netplan/50-cloud-init.yaml'
  --delete '/var/lib/dbus/machine-id'
  --delete-ssh-hostkeys \
  --run-command 'truncate -s 0 /etc/hostname' \
  --run-command 'hostnamectl set-hostname localhost' \
  --run-command 'truncate -s 0 /etc/machine-id' \
  --run-command 'ln -s /etc/machine-id /var/lib/dbus/machine-id' \
  --run-command 'passwd -d root' \
  --run-command 'truncate -s 0 ~/.bash_history' \
  --run-command 'history -c'
  --run-command 'sudo apt clean'
  --run-command 'sudo apt autoremove'

with success!

root@pve:~# virt-sysprep -a /dev/pve/vm-103-disk-0
[   0.0] Examining the guest ...
[   7.7] Performing "abrt-data" ...
[   7.8] Performing "backup-files" ...
[   9.0] Performing "bash-history" ...
[   9.0] Performing "blkid-tab" ...
[   9.1] Performing "crash-data" ...
[   9.2] Performing "cron-spool" ...
[   9.3] Performing "dhcp-client-state" ...
[   9.3] Performing "dhcp-server-state" ...
[   9.3] Performing "dovecot-data" ...
[   9.3] Performing "ipa-client" ...
[   9.4] Performing "kerberos-hostkeytab" ...
[   9.4] Performing "logfiles" ...
[   9.9] Performing "machine-id" ...
[   9.9] Performing "mail-spool" ...
[   9.9] Performing "net-hostname" ...
[  10.0] Performing "net-hwaddr" ...
[  10.1] Performing "pacct-log" ...
[  10.1] Performing "package-manager-cache" ...
[  10.2] Performing "pam-data" ...
[  10.3] Performing "passwd-backups" ...
[  10.3] Performing "puppet-data-log" ...
[  10.3] Performing "rh-subscription-manager" ...
[  10.4] Performing "rhn-systemid" ...
[  10.5] Performing "rpm-db" ...
[  10.5] Performing "samba-db-log" ...
[  10.5] Performing "script" ...
[  10.5] Performing "smolt-uuid" ...
[  10.6] Performing "ssh-hostkeys" ...
[  10.6] Performing "ssh-userdir" ...
[  10.6] Performing "sssd-db-log" ...
[  10.7] Performing "tmp-files" ...
[  10.8] Performing "udev-persistent-net" ...
[  10.8] Performing "utmp" ...
[  10.8] Performing "yum-uuid" ...
[  10.9] Performing "customize" ...
[  10.9] Setting a random seed
[  11.0] Setting the machine ID in /etc/machine-id
[  11.1] Performing "lvm-uuids" ...
root@pve:~# 

root@pve:~# locate –i *vm-9001*
/dev/pve/vm-9001-cloudinit
/dev/pve/vm-9001-disk-0
/run/udev/links/\x2fpve\x2fvm-9001-cloudinit
/run/udev/links/\x2fpve\x2fvm-9001-cloudinit/b253:14
/run/udev/links/\x2fpve\x2fvm-9001-disk-0
/run/udev/links/\x2fpve\x2fvm-9001-disk-0/b253:13
root@pve:~#

[virto-sysprep-ubuntu][https://manpages.ubuntu.com/manpages/jammy/man1/virt-sysprep.1.html]

Cloud-Init_Support

you can install it, it shouldn’t break your install.

I’d install it with apt install –no-install-recommends –no-install-suggests libguestfs-tools.

just be aware that you can’t manage proxmox guests with libvirt.