Proxmox: Run Docker on Linux Containers (LXC)

In this post, I show you how to run Docker in your Linux Containers (LXC), allowing you to save on resource requirements typically required by a VM.

19 days ago   •   3 min read

By 0xBEN
Table of contents

Why Docker on a Linux Container?

Simply put – saving resources. Proxmox official support would always recommend that you run Docker in VMs, but the disadvantage to that is that VMs require more resources from the hypervisor. Running Docker in a Linux Container (LXC) will allow you to run Docker at a fraction of the resource requirements with much faster boot speeds.

Please Note: Any time you want to run Docker on a Linux Container, simply repeat the steps as documented here.

Using ZFS? These steps were tested on a Proxmox node configured with ZFS and no observable issues could be detected.





Preparing Proxmox

Ensure FUSE OverlayFS is Installed on the Hypervisor

apt clean && apt update
apt install -y fuse-overlayfs





Create a Linux Container and Test Functionality

Create the Linux Container

Right click your node and click 'Create CT'
Ensure the container is unprivileged and nesting is enabled
Choose your container template
Add a disk, size according to your needs
Allocate cores according to your needs
Allocate RAM according to your needs
Set your NIC parameters according to your environment
I am using my internal domain and DNS server for this VLAN
Click finish to create the container



Change a Few Container Options

Click on your container
Click 'Options'
Double-click 'Features'
Enable 'keyctl', 'Nesting', and 'FUSE'

You may now start the container.





Configure and Test Docker

Install and Configure FUSE OverlayFS on the Linux Container

apt clean && apt update
apt install -y fuse-overlayfs
ln -s /usr/bin/fuse-overlayfs /usr/local/bin/fuse-overlayfs



Install Docker Engine on the Linux Container

Since the image I am using is Debian 11, we can follow the official Docker Engine installation instructions for Debian.

Install Docker Engine on Debian
Instructions for installing Docker Engine on Debian

# Ensure pre-requisites are installed
apt install -y ca-certificates curl gnupg lsb-release

# Add Docker GPG key
mkdir -p /etc/apt/keyrings
curl -fsSL https://download.docker.com/linux/debian/gpg | gpg --dearmor -o /etc/apt/keyrings/docker.gpg

# Add Docker apt repository
echo "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/debian $(lsb_release -cs) stable" | tee /etc/apt/sources.list.d/docker.list > /dev/null

# Update sources and install Docker Engine
apt update
apt install -y docker-ce docker-ce-cli containerd.io docker-compose-plugin

# Test for successful installation
docker run hello-world





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