I’m working on this project of mine, freckles, for a while now, and this is sort of a ‘tangential use-case’ I though some of you might be interested in.
Basically, freckles tries to provide a way to generically describe provisioning-type tasks, and then execute those tasks in all sorts of environments (physical machines, virtual ones, remote servers, Docker build processes, etc.). Its design allows for different backends to do the provisioning/orchestration, but currently only Ansible is properly implemented. A shell-script one, as well as one that uses Terraform are in the works though.
There exist already some good strategies to provision LXD containers, or build images (cloud-init, config management tools like Ansible, Puppet, Chef, other things like Packer), but none of them are as easy and immediate as using Dockerfiles for Docker is, IMHO. Now, granted, often that is not necessary, since LXD is used for different type of environments than Docker, in a lot of cases. Plus, it’s easier to re-use tools like Ansible, Chef, etc. with LXD, since an LXD container is much more similar to a ‘normal’ machine than a Docker container is. Still, I think there is some space where LXD would profit from having a quick and easy way to provision new containers or create images, and share the ‘recipes’ for that in a single file.
Long story, longer, I wrote about how to use freckles to that effect here:
This is the tldr; from that post:
On a system that has freckles and LXD installed and working, put the following content into a file 'example-lxd.frecklet':
- nginx-service
- nginx-vhost-from-folder:
document_root: /var/www/html
default_server: true
use_https: false
- file-with-content:
owner: www-data
path: /var/www/html/index.html
content: |
<h1><i>freckles</i> says "Hello World", from {{:: from ::}}!</h1>
This will act as our ‘Dockerfile’, and describes how to install and configure Nginx to serve a static webpage. To create an LXD image from it, execute:
$ frecklecute lxd-image-from-frecklet-file \
--install-packer \
--source-image images:debian/10 \
--image-name freckles-image \
--frecklet-path $(pwd)/example-lxd.frecklet \
--frecklet-vars '{"from": "my first image"}'
Once that has finished, create a container from the new ‘freckles-image’ image:
$ lxc launch freckles-image freckles-test
To test whether the Nginx service that runs in the container works, issue:
$ curl http://<container_ip>
<h1><i>freckles</i> says "Hello World", from my first image!</h1>
Happy to answer any questions, or hear your thoughs, concerns and suggestions.
EDIT: explicitely mentioning alternatives