timstaley.comet

An Ansible role that provides an installation of the Comet VOEvent broker.

Outline

This role will install the bare minimum to get a Comet instance up and running, and won't actually do anything with the VOEvents they receive. The Comet-invocation script can be supplied as a role-argument, so you can easily change that to set up passing of VOEvents to your own custom code.

Deployment details

The scripts create a pair of non-sudo users, defined by default as cometdeploy and cometserve. VOEvent handling code and virtualenvs are dropped into /home/cometdeploy, then run in read-only mode as the cometserve user (this provides extra security in the worse-case scenario that Comet has some serious security exploit hole, e.g. to malformed packets). Logs etc are dumped into /home/cometserve/working_dir.

Usage

Setup

Note that building the LXML package (which is a dependency) usually requires significantly more than 512MB of RAM. For the test-VM setup we make use of a swapfile, via a ready-made role from kamaln7. You'll need to install the role using the ansible-galaxy command line tool before running the tests.

Vagrant VM for testing

To pull up a working VM with Comet installed:

cd vagrant
ansible-galaxy install -r requirements.txt
vagrant up

Ansible on a pre-existing Ubuntu installation

Running against a pre-existing machine is a bit more complicated because there are more possible variables, and you may want to familiarize yourself with the Ansible docs first. In short, you'll need to:

• Configure your ansible inventory to reach the desired machines. Test with e.g. ansible -m ping all.
• Modify test-comet-role.yml as required. You probably don't want/need swapfile configuration, and you will need to set the hosts to match your inventory.
• Run your new playbook file using the ansible-playbook command.