Debian 11 Template

Creating a VMware Virtual Machine (VM) template using Debian 11 “Bullseye”

You can use a standalone ESXi host, or vCenter server to complete this guide. We will be using vCenter for our example screenshots. This guide is written based on ESXi/vCenter 7.0, but should work on all other supported releases (6.5/6.7). You could also use the popular Windows/MacOS based VMware Workstation/VMware Player to follow these instructions with some adaptation, but this guide will focus on ESXi/vCenter.

Prerequisites

• VMware ESXi Host (with or without vCenter) with at least 2 GB RAM and 35 GB storage free
• Debian 11 NetInst CD ISO* (https://www.debian.org/distrib/netinst)
• SCP client such as WinSCP (https://winscp.net/eng/download.php)

*NetInst CD ISO should be used over DVD. DVD ISO self-installs as a package source and must be re-mounted or manually removed from sources to update OS.

Create the Virtual Machine (VM)

• Log in to your vCenter or ESXi host
• Upload the Debian 11 ISO to a datastore on your host
• Create a new VM with the following specifications:
  • Virtual machine name: Debian11-Template
  • Guest OS Family: Linux
  • Guest OS Version: Debian GNU/Linux 11 (64-bit)
  • 1 CPU
  • 2 GB Memory
  • 30 GB Hard Disk (Thin Provision)*
  • SCSI Controller: VMware Paravirtual**
  • Network: Any port group with internet connectivity (preferably DHCP enabled)
  • Video card: Reduce Video Memory to 4 MB***
  • CD/DVD drive: Select “Datastore ISO File” – browse to Debian Netinst ISO uploaded previously and tick box for “Connected”

Note: The above CPU/Memory/Hard Disk are a recommended minimum. You may choose to increase (or decrease) these as you see fit in your template based on your environment’s needs/resource constraints.

* Thin provisioning is not the default (Except in NFS storage) and must be selected manually by expanding “Hard Disk 1” and using the dropdown menu
** This should be the default setting but included as a double-check
*** 4 MB video memory allows for resolutions up to 1360×768 which is enough for most use cases. If you want to use a GUI with high resolution you can increase this to 8 MB (resolutions up to 1600×1200), 16 MB (resolutions up to 2560×1600) or higher.

Configure the VM

Step-By-Step Screenshots of Install Process

• Power on the VM and connect to Console
• Select Graphical Install and press Enter
• Select English (or your language)
• Select United States (or your region)
• Select American English (or your keyboard layout)
• If DHCP not available:
  • Select “Configure Network Manually”
  • Enter desired IP address
  • Enter netmask
  • Enter gateway
  • Enter DNS servers (separated by space)
• Enter Hostname: localhost
• Leave Domain name blank
• Leave Root password blank (we will be using sudo for root)
• Enter Full name: debian
• Enter Username: debian
• Enter Password: debian
• Select your Time Zone
• Select “Guided – user entire disk and set up LVM”
• Select your disk (sda)
• Select “All files in one partition”
• Select “Yes” under “Write the changes to disks and configure LVM”
• Accept the default size (should be the entire drive) or enter “max”
• Select “Yes” under “Write the changes to disk”
• Select “No” under “Scan extra installation media”
• Select United States (or your country)
• Select default mirror (or mirror of your choice)
• Leave proxy blank
• Choose the Package Survey option which works for you:
  • “No” if privacy is a concern or for production
  • “Yes” to provide feedback to developers in non-production/home lab environments
• Software selection screen:
  • Remove: Debian Desktop Environment, GNOME
  • Select: SSH server (standard system utilities should be selected by default)
• Select “Yes” under “Install the GRUB boot loader to your primary drive?””
• Select your primary drive (/dev/sda)
• Once you reach the “Installation Complete” screen, return to ESXi/vCenter and revert the Virtual Machine’s CD/DVD drive to “Client Device”
• Return to the Virtual Machine console and click “Continue”

Update and Generalize the VM

Debian 11 is now installed on your Virtual Machine.

After a few moments the system will start up and prompt you for a username and password – use the credentials we set up during install (user: debian / pass: debian)

Run this command to get your server’s IP address:

ip address

Open your SCP client (I am using WinSCP) and enter the following:

• Host name: IP Address obtained above
• User name: debian
• Password: debian

Select “Yes” when prompted to accept the host key

Download and unzip the “scripts” folder to your computer from the following link:

Disclaimer: These scripts are not meant to be run on existing Linux installations and may have unpredictable or undesirable behavior in those environments. Scripts are provided as-is with no implied warranty. As with any script or automation, it is recommended you review the contents and familiarize yourself with what each script does. There is also an outline of the functions of each script included in the “Extras” section below.

Use SCP to transfer the “scripts” folder to the home directory on your VM (/home/debian)

The scripts folder contains 4 files:

• readme.txt
• debian-prep.sh
• gui-debian-prep.sh
• updates.sh

readme.txt (cat ~/scripts/readme.txt) provides descriptions and instructions for updates.sh and gui-debian-prep.sh

debian-prep.sh is the first script we will run and prepares the VM to be used as a template.

gui-debian-prep.sh is an optional script which installs a Desktop Environment/GUI (Graphical User Interface) it should only be run *after* deployment, not as part of templating

updates.sh updates the server operating system and installed packages

Return to the VM console and run the following commands:

chmod +x ~/scripts/debian-prep.sh
sudo ~/scripts/debian-prep.sh

Once the process completes, the VM will be shut down to complete the templating process.

Finalize the Template

In vCenter – right-click the VM and select Template > Convert to Template to mark the VM as a template

Use the template to deploy new Virtual Machines by right-clicking and selecting “New VM from this Template…”

Post-Deployment

Once deployed, you may update the server by using the following commands (chmod is only necessary first time):

chmod +x ~/scripts/updates.sh
sudo ~/scripts/updates.sh

If you wish to add a Desktop Environment/GUI to the server:

chmod +x ~/scripts/gui-debian-prep.sh
sudo ~/scripts/gui-debian-prep.sh

Extras:

What does debian-prep.sh do?

• Creates basic network config(/etc/network/interfaces)
• Installs updates and basic packages
• Clears Machine-ID to be regenerated at next boot*
• Clears DHCP info
• Sets default user (debian) password to expired**
• Clears command history
• Shuts down VM to complete templating process

* Machine-ID is generated if missing at boot. This should be unique for each VM, and must be cleared again (Re-Generalize instructions below) if template is booted up for future updates
** At first boot, user “debian” will need to set a new password. This is forced for security purposes

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What does gui-debian-prep.sh do?

• Updates the operating system and packages
• Installs Xfce4 desktop environment and additional plugins
• Installs graphical text editor (Geany) and web browser (Firefox)
• Removes unnecessary packages
• Reduces default workspaces (virtual desktops) from 4 to 1
• Sets up Greeter (login screen) to mimic look and feel of Xubuntu (official Ubuntu Xfce4 distribution)
• Removes unnecessary icons from panel (taskbar) and mimics look and feel of Xubuntu
• Self-deletes and reboots server to complete install

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How to Re-Generalize the Template

If you need to boot the template to perform updates or make other changes, you will need to Re-Generalize to prevent Machine-ID overlaps and remove any sensitive command history. Once you are finished with your changes run the following commands before converting back to template:

sudo -i
truncate -s0 /etc/resolv.conf
truncate -s0 /etc/machine-id
rm /var/lib/dbus/machine-id
ln -s /etc/machine-id /var/lib/dbus/machine-id
truncate -s0 ~/.bash_history
truncate -s0 /home/debian/.bash_history
shutdown -h now