onedocker

ONE Docker project - an attempt to dockerize OpenNebula

DISCLAIMERS (read them or do not complain)

• This is Work-In-Progress and Proof-of-Concept kind of thing - so it does not strive to be the definitive answer how to tackle this problem. This PoC also does not try to follow best-practices, patterns or guidelines how to create proper docker/microservice/container focused deployment. So do not draw much inspiration from this... (It may resemble more of a system containers rather than microservice containers...) Also due to the limitations in both the docker and the podman the current state is just a working set of workarounds.
• For the time being only podman and podman-compose is supported because of systemd which cannot run inside the docker (while OpenNebula uses systemd services). Also due to the limits in the podman (podman-in-podman functionality and problematic support of docker.sock) the opennebula-frontend container must be run under the root user if Docker Hub marketplace should work (otherwise it is fine).
• I tried to support more than one distro but CentOS is the recommended for now. The problem is that currently systemd is needed inside the images (until I port OpenNebula systemd services to some other init system) and unfortunately Debian flavoured images keep crashing my host system for some reason (podman/systemd version messing with my cgroup?).
• Both containers (opennebula-frontend and opennebula-node) are running as privileged - bear that in mind...
• There is already a rewrite of systemctl services to supervisord in OpenNebula project (for the official ONE Docker image) - I plan to base runit rewrite on them once they are published and proper support for docker thanks to it...

Usage

IMPORTANT 1:

You must have installed podman (some later version 2+ preferably) and podman-compose. The podman-compose is in early stages of development and not all docker-compose features are supported - therefore I recommend to use the devel version which may support more attributes found in my docker-compose.yml rather than a version of podman-compose installed via distro packages:

$ curl -o /usr/local/bin/podman-compose https://raw.githubusercontent.com/containers/podman-compose/devel/podman_compose.py
$ chmod +x /usr/local/bin/podman-compose

IMPORTANT 2:

While not mandatory I recommend to install docker on the host anyway and it IS mandatory (as of now) if you wish to use OpenNebula's Docker Hub marketplace. Podman in podman is a buggy mess and has too many issues to make it work (as of now).

Check your versions:

$ podman version
Version:      2.0.6
API Version:  1
Go Version:   go1.14.6
Built:        Tue Sep  1 21:26:51 2020
OS/Arch:      linux/amd64
$ podman-compose version
using podman version: podman version 2.0.6
podman-composer version  0.1.7dev
podman --version
podman version 2.0.6
0

Build and start ONE Docker

NOTE:

Without sudo the Docker Hub marketplace will not work (and possibly other things).

$ git clone https://github.com/ospalax/onedocker.git
$ cd onedocker
$ podman-compose up --build -d

or for Debian flavour (not recommended - it randomly crashes):

$ ONEDOCKER_OS=debian podman-compose up --build -d

If you wish to use Docker Hub marketplace then you must uncomment docker.sock volume in the docker-compose.yml for opennebula-frontend container (service) and run with sudo:

$ sudo podman-compose up --build -d

By default the OpenNebula's frontend (Sunstone web UI) will be accessible at http://localhost:9869. You can login there with oneadmin/changeme123 credentials.

Inside this repo is the file .env where are defined default values used by docker-compose/podman-compose to start this application/service deployment.

You are encouraged to change these values.

Stop ONE Docker

$ cd onedocker
$ sudo podman-compose down

Description

This project is trying to create full-featured OpenNebula installation/deployment implemented via application containers. The advantages are clear:

• simple and reproducible deployment
• easy switch to different OpenNebula version
• support for multiple instances running simultaneously
• overall ease-of-use for prototyping and testing of different OpenNebula versions

ONE Docker is reusing the OpenNebula's service files which are systemd's units - for that reason the systemd is needed to be running inside the container. The problem is that systemd inside a docker container fails to start and it is supported only by podman family of tools.

NOTE:

There is a plan to create an alternative - more docker friendly - version which will not be relying on systemd but it will utilize some other init system more suited for container environment (runit?).