openHAB on Ubuntu Snappy

Ubuntu snappy is a package manager for the minimalistic Ubuntu server variant Ubuntu Core, previously called JeOS. snappy supports transactional updates and rollbacks. It's designed to run on low power devices and virtual machines.

With snappy, you can install so called snaps, which can contain Frameworks or Apps, like openHAB.

This is all about openHAB 1. For version 2, instructions will be added later.

Hint: At the moment, snappy is changed very rapidly. We depend on some changes, so we wait for a bit stabilization there.

Installation

The further steps are tested on an ODROID C1. See other supported hardware on Ubuntu Core website.

ssh ubuntu@<ip-of-your-snappy-core-device>
sudo snappy update && sudo reboot
sudo snappy install openhab

Hint: Currently (March, 2nd 2015), the snappy repo does not contain openHAB. Please follow the Create the openHAB snap instructions to build a snap.

Create the openHAB snap

On a development machine, running ubuntu:

sudo add-apt-repository ppa:snappy-dev/beta
sudo apt-get update && sudo apt-get upgrade
sudo apt-get install snappy-tools git-core
git clone https://github.com/sja/openhab-snappy.git
cd openhab-snappy
# make changes, extract jdk and openhab to its folders
snappy build .
snappy-remote --url=ssh://<ip-of-your-snappy-core-device> install ./*.snap

The previous steps add the snappy ppa to your repositories, install the snappy tools and clone the install files to build a snap. Now you can make changes to the configuration or startup scripts or whatever you want.

Keep in mind, that AppArmor will prevent you from accessing files or folders, you create on "unusual" paths. Have a look in meta/openhab.profile, where the process spawned by calling bin/startup.sh is restricted and see, what "unusual" means. Maybe you have to extend the profile. The man page of AppArmor will help you with the right flags.

The .snap file is just an ar archive, which you can extract with ar x *.snap if you're curious what you have packaged before.

The command snappy-remote will install or update the snap on your snappy core host. Depending on the hardware, that step can take some time. At the moment, an openHAB 1.6 with demo files and JDK 1.8 will result in a 180MB snap. But that will be optimized in future.

Debug a snap

If something does not work, then maybe check the following steps:

• Can you reach your snappy core host from the dev machine? ping <ip-of-your-snappy-core-device> should give you an answer.
• Is there enough disk space? df -h
• Does your snappy core device work as intended? Use a serial console (if available) or call dmesg after some minutes of operation and search for CRC errors. Some devices are sensitive for some memory cards. dmesg | grep -i crc
• Delete the snap and recreate it with snappy build.
• Maybe you have any AppArmor violations. Open a second console or ssh session and call journalctl -f -k. Then install your snap or, if it is already installed, call aa-exec -p openhab_openhab_1.x.x -- /apps/openhab/1.x.x/bin/start.sh on the other console. Have a look at the output of the first Terminal. A bad example would be something like that: type=1400 audit(1425307113.805:9): apparmor="DENIED" operation="exec" profile="openhab_openhab_1.6.2" name="/apps/openhab/1.x.x/jdk/bin/java" pid=1194 comm="start.sh" requested_mask="x" denied_mask="x" fsuid=0 ouid=0. This was, because start.sh tried to execute /apps/openhab/1.x.x/jdk/bin/java, which was not allowed by the profile.