LXC Fresh Container Construction From Scratch for Proxmox

nospam@example.com (Raymond P. Burkholder) — Fri, 27 Feb 2026 21:03:19 +0000

There are many articles available which discuss customizing a pre-existing Proxmox Container Template. Few, if any, discuss constructing an LXC container from scratch. Maybe because, fundamentally, a container template is just the rootfs as tarball, so building it is quite easy:

Build a linux based virtual machine, I use Debian's recent release
Install LXC and its template package
Construct and initialize an LXC container
Shut it down and and zip it up
Copy it over to the ProxMox template directory

The details:

# build the linux vm - details not relevant here
# ssh into the vm, or start a command line
# install basic packages

sudo apt install --no-install-recommends lxc lxc-templates xz-utils bridge-utils wget debootstrap rsync

# basic container templates are in:
#   /usr/share/lxc/templates/ 
# for debian as well as other distributions

# create an lxc container, provide a list any additional packages

lxc-create --template debian --name trixie-template -- --release trixie --packages iputils-ping,vim-tiny

# start and attach to the container
lxc-start trixie-template
lxc-attach trixie-template

# prepare for generating template
apt clean
apt purge

# Remove SSH host keys to ensure unique keys for each clone:
rm /etc/ssh/ssh_host_*

# Empty the machine ID file:
truncate -s 0 /etc/machine-id

# clear history
unset HISTFILE
# truncate history
history -c
> ~/.bash_history
# the following has a space in front to prevent inclusion in the history
 shutdown -h now

# the shutdown returns to the virtual machine's prompt
# compress the directory structure

cd /var/lib/lxc/trixie-template/

# remove /dev files as they can't be created in an unprivileged container
# an example error message if not removed:
#   tar: ./rootfs/dev/urandom: Cannot mknod: Operation not permitted
# construction of a new container will re-create the directory and files

rm ./rootfs/dev/ptmx
rm ./rootfs/dev/zero
rm ./rootfs/dev/tty3
rm ./rootfs/dev/urandom
rm ./rootfs/dev/null
rm ./rootfs/dev/tty
rm ./rootfs/dev/console
rm ./rootfs/dev/tty4
rm ./rootfs/dev/tty2
rm ./rootfs/dev/random
rm ./rootfs/dev/tty1
rm ./rootfs/dev/full

# cd into rootfs and zip the container

cd rootfs
tar --xz --acls --numeric-owner -cf /var/local/trixie-13-3-template.tar.xz ./

# the xz file can be copied over to proxmox and placed into
# /var/lib/pve/local-btrfs/template/cache/
# for use as a template for container creation

During the first use of lxc-create to create the original container, packages are downloaded and installed to build the container. The packages and installation is cached for faster subsequent builds of the same container type.

If the cache becomes stale, it can be rebuilt by using --flush-cache in a manner similar to:

lxc-create --template debian --name trixie-template -- --release trixie --flush-cache --packages iputils-ping,vim-tiny,less,python-minimal

An existing cache can be updated with something like:

sudo chroot /var/cache/lxc/debian/rootfs-trixie-amd64
apt-get update
apt-get dist-upgrade
apt-get clean
exit

courtesy of Updating lxc image/container caches

One other note, there are two package candidates for installing the ping utility:

iputils-ping - native Linux ping, preferred for Debian/Linux
inetutils-ping - general gnu version, used on a variety of posix sytstems, less preferred

Some fix-ups in the process:

apt-get install less
dpkg-reconfigure locales
useradd user

Image Building Notes - debootstrap

nospam@example.com (Raymond P. Burkholder) — Sun, 05 Apr 2026 17:31:32 +0000

APT based distributions like Debian can be containerized with a tool called debootstrap. It is part of the image build process of lxc-create. It is also referenced in Docker Base Images for building an image from scratch.

When looking at the build scripts included in the package installation, repositories for the following distributions can be found in /usr/share/debootstrap/scripts:

debian - universal operating system
trisquel - a distribution of the GNU operating system, with the kernel GNU Linux-libre
ubuntu - modern enterprise open source
pardus - Turkish
kali - open-source, Debian-based Linux distribution geared towards various information security tasks, such as Penetration Testing, Security Research, Computer Forensics and Reverse Engineering
elxr - Enterprise-Grade Linux for Edge-to-Cloud Deployments
pureos - fully-convergent, user friendly, secure and freedom respecting OS for your daily usage

The wiki shows a simple two liner to get the basics of the distribution in place (as root):

mkdir trixie-chroot
debootstrap stable trixie-chroot http://deb.debian.org/debian/

Enter the chroot and note new root:

root@test:~# pwd
/root
root@test:~# chroot trixie/
root@test:/# pwd
/
root@test:/# exit
exit
root@test:~# pwd
/root

After the debootstrap, create the base for docker, and give it a try:

tar -C trixie-chroot -c . | docker import - trixie
docker run trixie cat /etc/debian_version
docker run --rm -i -t trixie /bin/bash

Although debootstrap can be used to build an image for a version subsequent, it is generally recommended to use debootstrap from at least the desired version to ensure it has the proper updates and dependencies.

Command line to summarize the referenced repositories:

grep -h default_mirror /usr/share/debootstrap/scripts/* \
  | sed 's/default_mirror//' \
  | sed 's/[ \t]//g' \
  | sort \
  | uniq

Raymond P. Burkholder - Things I Do - Containers

LXC Fresh Container Construction From Scratch for Proxmox

Image Building Notes - debootstrap