I am excited to experiment more with https://resin.io/ I started playing around with it last night and it is pretty slick for getting up and running developing a standard maintainable fleet of devices out in the field. It lets you enter a wifi network and password in the web ui when generating the OS image (which is only 147mb). Then when you boot the pi for the first time it connects to wifi and to the Resin.io dashboard.
Key features
- Simple web-based networking setup
- Docker-based
- Remote ssh access
- Remote system
- Designed to manage multiple identical devices
Take a look at https://docs.resin.io/learn/getting-started/raspberrypi3/nodejs/ to try it out.
They are doing a lot of open source but not fully yet https://resin.io/blog/the-status-and-future-of-open-source-resin-io/