As we struggle with installs we wonder if docker might help in the long run. It certainly has advantages in the short run.
# Transporters
We've had some trouble keeping the image transporter running when ruby, sinatra and graphviz install dependencies compound. We're not sure how docker makes this easier but it does. github 
We modeled our build on one simple example. github
Only our newest droplet was running the sufficiently recent Ubuntu 16.04 for the DigitalOcean Docker install instructions to work. post
We build on the platform rather than registering our image in any repository. We've yet to psych out the various repository policies.
We need something like upstart or systemd to keep our container working. Ubuntu versions vary in what they provide.