Docker-Pi – Getting Started

Setup Raspberry Pi2 with HypriotOS

This gives us the basic docker platform to start from.. saves the agro of trying to work it all out for ourselves.  The guys over at Hypriot have put together a baseline OS for the ARM/Pi architecture that boots, DHCPs for network and then automatically starts the Docker components.
Download from here, and if you run a mac, follow these instructions.
The default SSH credentials for HypriotOS are pirate (username) / hypriot (password).

Assign static addressing

If you’re like me, you can’t remember half of the distribution variations for setting a static address.. HypriotOS is based on Debian – so the following would work fine: edit /etc/network/interfaces/eth0
auto eth0
iface eth0 inet static
 address 192.168.1.111/24
 gateway 192.168.1.1
 dns-nameservers 192.168.1.1
 dns-search jimleach.co.uk

Getting Persistance

Docker instances are non-persistant, but for most of the things I want to use them for, I need some consistent storage I can present to them.  Don’t do this if you want your containers to be portable! A better way would be to present some storage via NFS and map that instead.. something a bit less host-centric.

HypriotOS/armv7: pirate@black-pearl in /var/docker_data
$ pwd
/var/docker_data

Create directories for:

  • dockerui
  • influxdb
  • telegraf
  • grafana

We’ll need these later as we build up our stack of containers..

Docker-UI

Docker itself doesn’t have a web-frontend, it’s all CLI driven – but Docker-UI is a container-made app that allows you to see all the images and containers in your docker engine and view the connectivity between them.  Hypriot have pre-compiled the UI for their OS, and you can grab directly from the docker hub and manually run or, or by the power of docker, just run it (without downloading first) and let docker do the hard work:
HypriotOS/armv7: pirate@black-pearl in ~
$ docker run -d -p 9000:9000 -v /var/run/docker.sock:/var/run/docker.sock -v /var/docker_data/dockerui:/data --name dockerui hypriot/rpi-dockerui
Unable to find image 'hypriot/rpi-dockerui:latest' locally
latest: Pulling from hypriot/rpi-dockerui
f550508d4a51: Pull complete
a3ed95caeb02: Pull complete
Digest:sha256:6e245629d222e15e648bfc054b9eb24ac253b1f607d3dd513491dd9d5d272cfb
Status: Downloaded newer image for hypriot/rpi-dockerui:latest
34d0b3f00a25e847743fd04b59952d7870f2bebbd3b7524e009afd6d5fd0404c

By trying to run the image without first downloading, you prompt docker into pulling it automatically from the Docker Hub and then starting it.

  • -d – Puts the instance into daemon mode
  • -p 9000:9000 – maps port 9000 on the localhost (the RiPi) to port 9000 on the instance
  • -v – Maps our local storage to a volume/directory in the container (local:container)
  • –name – gives us a recognisable name to reference the container with

Now if you browse to the Pi’s address on port 9000 – you should get the Docker UI:

screen-shot-2016-09-18-at-16-33-44