Creating Your Own ProxCP KVM Templates

This tutorial covers how to create a custom KVM template for use with ProxCP and Proxmox.

Required: at least 1 Proxmox node

Assumption: The desired operating system ISO is already downloaded onto your Proxmox node.

The commands covered here are relevant to Debian and RHEL-based operating systems however the process can be applied to any other operating system.

Create VM

• Create a new VM in Proxmox with the following settings:
  • VMID: anything
  • Name: operating system description (i.e. centos-8-amd64)
  • OS: your chosen ISO image
  • Hard Disk: use VirtIO SCSI (scsi0) with 10GB storage and no caching
  • CPU & Memory: 1 kvm64 CPU core, 1GB memory
  • Network: VirtIO (virtio0), vmbr0 bridge, no firewall
• After creation, go to the Hardware tab and delete the CDROM ISO. Add a cloud-init drive on ide2. Add the CDROM ISO back as ide0.

Base OS

• Boot the new VM and complete the base operating system installation. Generally, templates should use most default settings and minimal packages. There are a few things to keep in mind during installation:
  • Partitions: create 1 ext4 root "/" partition (no LVM, no SWAP)
  • Networking: use a generic hostname (i.e. localhost or centos-8-amd64)
  • Packages: use minimal packages, however the OpenSSH server is required

OS Setup Stage 1

• Once the base OS installation is complete, shutdown the VM
• In Proxmox, go to Options and set the boot order to scsi0 only (1 option)
• Go to the Hardware tab and remove the ide0 CDROM. Verify the network device is net0 using vmbr0 bridge
• Power on the VM
• Login as root
• If you created a user during installation, remove that user with deluser [username] && rm -rf /home/[username]
• Complete updates apt update && apt upgrade && apt install setserial or yum update && yum install setserial

Serial Console Setup

KVM templates have to be configured to use a serial console for noVNC access.

• Edit the /etc/default/grub file:
  • Add or replace

GRUB_CMDLINE_LINUX='quiet console=tty0 console=ttyS0,115200'
GRUB_TERMINAL=serial
GRUB_SERIAL_COMMAND="serial --speed=115200 --unit=0 --word=8 --parity=no --stop=1"

• Save the file
• Run update-grub (debian/ubuntu) or grub2-mkconfig -o /boot/grub2/grub.cfg (centos/rhel)
• Run cat /etc/securetty | grep ttyS0 and ensure ttyS0 is in /etc/securetty. This file may not exist which is okay.

If you are creating a template for a newer operating system using "systemd":

• Run systemctl enable serial-getty@ttyS0.service && systemctl start serial-getty@ttyS0.service

Next:

• Shutdown the VM shutdown -h now
• In Proxmox go to the Hardware tab and add a Serial Port (serial0) then set the Display to Serial Terminal 0 (serial0)
• Start the VM

OS Setup Stage 2

• Login as root
• Edit /etc/ssh/sshd_config and ensure Port is 22 and PermitRootLogin is yes
  • It is best to uncomment these lines to explicitly declare these settings
• Install any other software you want to include in this template
  • Some good examples to include: htop bmon zip unzip wget nano curl ethtool net-tools
• Confirm with fdisk -l that there are no other disk partitions after root "/"

Cloud-init

• Install cloud-init:
  • Debian/Ubuntu: apt install cloud-init cloud-initramfs-growroot cloud-guest-utils xfsprogs gdisk
  • CentOS/RHEL: yum install cloud-init cloud-utils-growpart cloud-guest-utils xfsprogs libicu gdisk
• Proxmox requires cloud-init 18.2 or newer cloud-init --version