[[qm_cloud_init]]
Cloud-Init Support
------------------
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:pve-toplevel:
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http://cloudinit.readthedocs.io[Cloud-Init] is the defacto
multi-distribution package that handles early initialization of a
virtual machine instance. Using Cloud-Init, one can configure network
devices and ssh keys on the hypervisor side. When the VM starts the
first time, the Cloud-Init software inside the VM applies those
settings.

Many Linux distributions provides ready-to-use Cloud-Init images,
mostly designed for 'OpenStack'. Those images also works with
{pve}. While it may be convenient to use such read-to-use images, we
usually recommend to prepare those images by yourself. That way you know
exactly what is installed, and you can easily customize the image for
your needs.

Once you created such image, it is best practice to convert it into a
VM template. It is really fast to create linked clones of VM
templates, so this is a very fast way to roll out new VM
instances. You just need to configure the network (any maybe ssh keys)
before you start the new VM.

We recommend the use of SSH key-based authentication to login to VMs
provisioned by Cloud-Init. It is also possible to set a password, but
{pve} needs to store an encrypted version of that password inside the
Cloud-Init data. So this is not as safe as using SSH key-based
authentication.

{pve} generates an ISO image to pass the Cloud-Init data to the VM. So
all Cloud-Init VMs needs to have an assigned CDROM drive for that
purpose. Also, many Cloud-Init Images assumes to have a serial
console, so it is best to add a serial console and use that as display
for those VMs.


Prepare Cloud-Init Templates
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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

----
apt-get install cloud-init
----

Many distributions provides ready-to-use Cloud-Init images (provided
as `.qcow2` files), so as alternative you can simply download and
import such image. For the following example, we will use the cloud
images 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
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

# finally attach the new disk to the VM as scsi drive
qm set 9000 --scsihw virtio-scsi-pci --scsi0 local-lvm:vm-9000-disk-1
----

NOTE: Ubuntu Cloud-Init images requires the `virtio-scsi-pci`
controller type for SCSI drives.


.Add Cloud-Init CDROM drive

[thumbnail="gui-cloudinit-hardware.png"]

The next step is to configure a CDROM drive, used to pass the
Cloud-Init data to the VM.

----
qm set 9000 --ide2 local-lvm:cloudinit
----

We want to boot directly from the Cloud-Init image, so we set the
`bootdisk` parameter to `scsi0` and restrict BIOS to boot from disk
only. This simply speeds up booting, because VM BIOS skips testing for
a bootable CDROM.

----
qm set 9000 --boot c --bootdisk scsi0
----

We also want to configure a serial console and use that as display. Many Cloud-Init images rely on that, because it is an requirement for OpenStack images. 

----
qm set 9000 --serial0 socket --vga serial0
----

Finally, it is usually a good idea to transform such VM into a template. You can create linked clones with them, so deployment from VM templates is much faster than creating a full clone (copy).

----
qm template 9000
----


Deploy Cloud-Init Templates
~~~~~~~~~~~~~~~~~~~~~~~~~~~

[thumbnail="gui-cloudinit-config.png"]

You can easily deploy such template by cloning:

----
qm clone 9000 123 --name ubuntu2
----

Then configure the SSH public key used for authentication, and the IP setup

----
qm set 123 --sshkey ~/.ssh/id_rsa.pub
qm set 123 --ipconfig0 ip=10.0.10.123/24,gw=10.0.10.1
----

You can configure all Cloud-Init options using a single command. I
just split above example to separate commands to reduce the line
length. Also make sure you adopt the IP setup for your environment.



Cloud-Init specific Options
~~~~~~~~~~~~~~~~~~~~~~~~~~~

include::qm-cloud-init-opts.adoc[]