Linux Piter 2016

Building a PaaS with Docker, Consul and Pyth

I'm currently single-handedly building a Database-As-A-Service platform. And the problem of where and how to run database instances has been successfully solved in favor of Docker. But there still remain 2 problems: how to link containers on different hosts across the network and how to orchestrate a large pool of running instances.

You may find lots of different IaaS offerings and schedulers like Mesos and Kubernetes on the market, but all of them have a steep learning curve. Plus they don't handle stateful and non-SOA services very well.

In this talk I'll be walking you over how one can build a simple PaaS based on Docker, consul and a custom orchestration service in Python. My experience in building such system shows that it can be reproduced by the effort of one developer.

A list of topics I will cover:
- Consul as a reliable distributed storage
- Connecting containers between hosts without an overlay network
- Allocating IP addresses and maintaining their pool in Consul KV
- Correctly registering services and health checks
- How to approach writing basic orchestrator based on gevent + writing trivial admin UI for it
- Adding failover, scaling and service reallocation to the orchestrator
- Delayed tasks (backup, analytics, etc...)
- Monitoring the system (Consul + Prometheus)

Almost all code of the system, including ansible playbooks, is available on GitHub.

Konstantin Nazarov
Russia. Moscow
SRE
Tarantool

Konstantin Nazarov is an infrastructure engineer in Tarantool team. In the past was a system programmer and a fan of Common Lisp. Minimalist and adept of iterative approach to everything.