piku

The tiniest Heroku/CloudFoundry-like PaaS you've ever seen, inspired by dokku.

Motivation

I kept finding myself wanting an Heroku/CloudFoundry-like way to deploy stuff on a few remote ARM boards and my Raspberry Pi cluster, but since dokku didn't work on ARM at the time and even docker can be overkill sometimes, I decided to roll my own.

Project Status/To Do:

This is currently being used for production deployments of my website and a few other projects of mine that run on Azure and other IaaS providers. Regardless, there is still room for improvement:

From the bottom up:

• Prebuilt Raspbian image with everything baked in
• chroot/namespace isolation (tentative)
• Relay commands to other nodes
• Proxy deployments to other nodes (build on one box, deploy to many)
• Support Clojure/Java deployments through boot or lein
• Support Node deployments
• Sample Go app
• Support Go deployments (in progress)
• nginx SSL optimization/cypher suites, own certificates
• Let's Encrypt support
• Review deployment messages
• WIP: Review docs/CLI command documentation (short descriptions done, need help <cmd> and better descriptions)
• Allow setting nginx IP bindings in ENV file (NGINX_IPV4_ADDRESS and NGINX_IPV6_ADDRESS)
• Cleanups to remove 2.7 syntax internally
• Change to Python 3 runtime as default, with PYTHON_VERSION = 2 as fallback
• Run in Python 3 only
• (experimental) REPL in feature/repl
• Python 3 support through PYTHON_VERSION = 3
• static URL mapping to arbitrary paths (hat tip to @carlosefr for nginx tuning)
• remote CLI (requires ssh -t)
• saner uWSGI logging
• gevent activated when UWSGI_GEVENT = <integer>
• enable CloudFlare ACL when NGINX_CLOUDFLARE_ACL = True
• Autodetect SPDY/HTTPv2 support and activate it
• Basic nginx SSL config with self-signed certificates and UNIX domain socket connection
• nginx support - creates an nginx config file if NGINX_SERVER_NAME is defined
• Testing with pre-packaged uWSGI versions on Debian Jessie (yes, it was painful)
• Support barebones binary deployments
• Complete installation instructions (see INSTALL.md, which also has a draft of Go installation steps)
• Installation helper/SSH key setup
• Worker scaling
• Remote CLI commands for changing/viewing applied/live settings
• Remote tailing of all logfiles for a single application
• HTTP port selection (and per-app environment variables)
• Sample Python app
• Procfile support (wsgi and worker processes for now, web processes being tested)
• Basic CLI commands to manage apps
• virtualenv isolation
• Support Python deployments
• Repo creation upon first push
• Basic understanding of how dokku works

Using piku

piku supports a Heroku-like workflow, like so:

• Create a git SSH remote pointing to piku with the app name as repo name (git remote add paas piku@server:app1)
• git push paas master your code
• piku determines the runtime and installs the dependencies for your app (building whatever's required)
  • For Python, it segregates each app's dependencies into a virtualenv
  • For Go, it defines a separate GOPATH for each app
• It then looks at a Procfile and starts the relevant workers using uWSGI as a generic process manager
• You can then remotely change application settings (config:set) or scale up/down worker processes (ps:scale) at will.

Internals

This is an illustrated example of how piku works for a Python deployment:

Supported Platforms

piku is intended to work in any POSIX-like environment where you have Python, uWSGI and SSH, i.e.: Linux, FreeBSD, Cygwin and the Windows Subsystem for Linux.

As a baseline, it began its development on an original, 256MB Rasbperry Pi Model B, and still runs reliably on it.

Since I have an ODROID-U2, a bunch of Pi 2s and a few more ARM boards on the way, it is often tested on a number of places where running x64 binaries is unfeasible.

But there are already a few folk using piku on vanilla x64 Linux without any issues whatsoever, so yes, you can use it as a micro-PaaS for 'real' stuff. Your mileage may vary.

Supported Runtimes

piku currently supports deploying apps (and dependencies) written in Python, with Go, Clojure (Java) and Node (see above) in the works. But if it can be invoked from a shell, it can be run inside piku.

FAQ

Q: Why piku?

A: Partly because it's supposed to run on a Pi, because it's Japanese onomatopeia for 'twitch' or 'jolt', and because I know the name will annoy some of my friends.

Q: Why Python/why not Go?

A: I actually thought about doing this in Go right off the bat, but click is so cool and I needed to have uWSGI running anyway, so I caved in. But I'm very likely to take something like suture and port this across, doing away with uWSGI altogether.

Go also (at the time) did not have a way to vendor dependencies that I was comfortable with, and that is also why Go support fell behind. Hopefully that will change soon.

Q: Does it run under Python 3?

A: Right now, it only runs on Python 3, even though it can deploy apps written in both major versions. It began its development using 2.7 and usingclick for abstracting the simpler stuff, and I eventually switched over to 3.5 once it was supported in Debian Stretch and Raspbian since I wanted to make installing it on the Raspberry Pi as simple as possible.

Q: Why not just use dokku?

A: I used dokku daily for most of my personal stuff for a good while. But it relied on a number of x64 containers that needed to be completely rebuilt for ARM, and when I decided I needed something like this (March 2016) that was barely possible - docker itself was not fully baked for ARM yet, and people were at the time trying to get herokuish and buildstep to build on ARM.