Learn how to create a custom LXD Debian Image. Our LXC/LXD Support team is here to help you with your questions and concerns.

How to create Custom LXD Debian Image

Today, we are going to create a custom LXD image based on a basic Debian installation. This works for local use or publishing.

1. To begin with, we have to install debootstrap.

   sudo apt install debootstrap

   This will let us create a minimal Debian system in a specified directory.
2. If LXD is not already installed and configured, we have to install updates on Debian box as seen here:

   $ sudo apt update
$ sudo apt upgrade
3. Then, it is time to create a minimal Debian installation in a specified directory.

   For instance, to install Debian Sid (unstable) in a temporary directory:

   mkdir /tmp/sid-lxd
sudo debootstrap sid /tmp/sid-lxd

   At this point, we have to enter the created chroot environment to make changes. This will make our container different. For example, to preconfigure the repository for Node.js:

   sudo chroot /tmp/sid-lxd
wget -qO- https://deb.nodesource.com/gpgkey/nodesource.gpg.key | apt-key add -
echo 'deb https://deb.nodesource.com/node_8.x sid main' > /etc/apt/sources.list.d/nodesource.list
echo 'deb-src https://deb.nodesource.com/node_8.x sid main' >> /etc/apt/sources.list.d/nodesource.list
exit

4. Then, we have to create a compressed tarball of the root directory of our newly installed system:

   sudo tar -cvzf rootfs.tar.gz -C /tmp/sid-lxd
5. Now, it is time to create a metadata.yaml file. It contains information like image creation date, architecture, name, and description. In order to create an LXD image, we need a metadata.yaml file.

   For example:

   architecture: "x86_64"
creation_date: 1458040200
properties:
architecture: "x86_64"
description: "Debian Unstable (sid) with preconfigured Node.js repository (20171227)"
os: "debian"
release: "sid"

6. After the metadata file creation, we have to create a tarball with the metadata file:

   tar -cvzf metadata.tar.gz metadata.yaml
7. Then, import the two tarballs as LXD images:

   lxc image import metadata.tar.gz rootfs.tar.gz --alias sid-nodejs
8. Then, we can create a new container from this image:

   lxc launch sid-nodejs tutorial
lxc exec tutorial bash

9. Next, verify if the container uses the Node.js repository with this command:

   sudo apt update && apt-cache show nodejs
10. Then, configure the LXD daemon to listen to the network and tag the image as public:

    lxc config set core.https_address "[::]:8443"

    Other users can now add our server as a public image server and create containers from our image.
11. Additionally, we can make our LXD image available for server users, by modifying the public parameter:

    lxc image edit sid-nodejs

    Here, change `false` to `true` in the last line, save the file, and we have shared our LXD image!

    Furthermore, we can see all available Debian OS templates by running:

    lxc image list images: debian

    We can easily create a container with Debian 10 OS as seen here:

    lxc launch images:debian/10 my-debian

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Conclusion

In brief, our Support Experts demonstrated how to create a custom LXD Debian Image.