CentOS/Rocky/Ubuntu Packer Builder for Proxmox

This project provides Packer files to build a basic image of either CentOS 7 or CentOS 8 for use on a Proxmox system. Use it as is or as a starting point for a more fully customized image.

This has been tested on Proxmox 7.x and 8.x.

Getting started

To use this you will need:

• This repo git clone https://github.com/dustinrue/proxmox-packer.git
• ISO files for the OS you want to build an image for uploaded to Proxmox:
  • CentOS Downloads
  • Rocky Linux
  • Ubuntu
• A working Proxmox system
• Packer. This project is tested with Packer version 1.9.2
• The builder machine must be accessible to Proxmox or you must host the ks.cfg or inst.ks files somewhere publicly accessible and modify the packer.pkr.hcl file for the version you wish to build.

The OS ISO file will need to be uploaded to your Proxmox system.

The simplest way to get the ISO file on your Proxmox system is to use the "Download from URL" option on the disk/share that you configured for ISO files.

Building an Image

You will first want to determine if your host running Packer can be accessed by the Proxmox host. This is because Packer will briefly run an http server so that the installer can download the kickstart file. If Proxmox is on the same network as your builder host and there are no other firewall restrictions on your builder host this should work fine. If not, you will need to copy/host the ks.cfg files on a publicly accessible server.

Next, you will need to know the URL to your Proxmox system, the name of the node to build on as well as a username and password of a user with sufficient privileges to create VMs and templates. If you have customized your install or are using a storage pool other than the default you will need to specify that as well.

With all of the information at hand, edit the variables.pkrvars.hcl file and update the variables. For a full set of variables you can override look at any packer.pkr.hcl file for a list of variables.

In addition to using the packer.pkr.hcl file you can also set some variables using environment variables. For example, I set my Proxmox password using the following variable:

PROXMOX_PASSWORD=<scrubbed>

Using the Makefile

You can build the following templates by running:

• make centos7
• make centos8
• make rocky8
• make rocky9
• make ubuntu2004
• make ubuntu2204
• make ubuntu2404

Building manually

If you do not want to use the Makefile then the following commands will work:

CentOS 7

packer build -var-file variables.pkrvars.hcl centos7/packer.pkr.hcl

CentOS 8

packer build -var-file variables.pkrvars.hcl centos8/packer.pkr.hcl

Rocky Linux 8

packer build -var-file variables.pkrvars.hcl rocky8/packer.pkr.hcl

Rocky Linux 9

packer build -var-file variables.pkrvars.hcl rocky9/packer.pkr.hcl

Ubuntu 20.04

packer build -var-file variables.pkrvars.hcl ubuntu2004/packer.pkr.hcl

Ubuntu 22.04

packer build -var-file variables.pkrvars.hcl ubuntu2204/packer.pkr.hcl

Ubuntu 24.04

packer build -var-file variables.pkrvars.hcl ubuntu2404/packer.pkr.hcl

Note that RL9 now requires at least an Intel Nehalem processor or equivalent. You can read more at https://www.phoronix.com/scan.php?page=news_item&px=RHEL-9-x86-64-v2-Plans

There are a number of other variables you can set. You will notice these closely match the available options for the Proxmox builder. The full list of variables you can customize is:

• proxmox_username - username to log into Proxmox as
• proxmox_password - password to log into Proxmox as
• proxmox_url - URL of your Proxmox system
• proxmox_node - name of the Proxmox node to build on
• proxmox_storage_pool - name of the storage pool the image should be built on
• proxmox_storage_pool_type - type of storage pool, lvm-thin (default), lvm , zfspool or directory
• proxmox_storage_format - storage format, raw (default), cow, qcow, qed, qcow2, vmdk or cloop
• centos_image or ubuntu_image - The OS image.
• template_name - Name of the template. Defaults to CentOS7-Template or CentOS8-Template depending on version
• template_description - Template description. Defaults to CentOS 7 Template or CentOS 8 Template depending on image being built.

After the image is built

Once the image is built you will want to adjust any remaining settings in the template including creating a cloud-init drive. A cloud-init drive must be created for you to ssh into any new VMs you create. For details on how to do so visit https://blog.dustinrue.com/proxmox-cloud-init/.