David Ventura - resume

Summary

Problem solver that spent the last 9 years mainly focusing on linux, automation and tooling, but also had problems push me through full-stack web development, distributed systems, database administration, mobile, networking and embedded systems.

Work Projects

2018 - current Optiver Sysadmin - Tooling developer

Responsible for production systems' behavior as well as keeping the design of new systems within our standards.

Established operational commitments for development teams to bring down application errors to monitorable state.
Mentored colleagues, healping them transition from an old-school sysadmin position to a tooling development position
Overhaul compliance related backup system (300TB+)
Deployment system for production services (11k services, 860 servers)
Linux-on-windows initiative and platform deployment to standardize the production os-level API across the existing services
Analysis of logs and events, to quickly detect production related incidents
Redesigned and fully automated physical server deployment
Redesigned and implemented market data permissioning system

2014 - 2018 Especificos Buenos Aires Sysadmin - Tooling - Backend dev - Frontend dev - Embedded - Networking

Responsible for interfacing directly with end users and designing the video streaming and e-learning platforms end-to-end, encompassing a very broad set of technologies.

Live-streaming Platform

The objective of this project was to create a pipeline for live video streaming, all the way from the physical cameras in the classroom to the software used by the alumni. A few key points covered by the project:

Embedded linux systems for the video cameras (running on on-prem raspberry pi), audio mixer and slide system
Live audio conferences to allow local and remote speakers to presnet together
Time syncing across video sources to prevent frame drift, using PTP
Slide software that allows presenter to draw on slides and alumni to ask questions to the presenter

Online training platform

The objective of this project was to create a ‘forum’-like website to post the videos with the corresponding text material, allowing the students to communicate with each other.

Billing System

The scope of this project was to manage most of the company's finances:

Billing, invoices (AFIP), shipping labels, e-commerce, local stock and supplier stock
Document scanning and printing

2014-2018 Freelancing

Streamall (netflix 'clone') Sysadmin - Backend dev - Frontend dev - Tooling - Distributed systems

In this project I designed and implemented a system that allowed hundreds of users to access thousands of long-form videos on demand, deployed on a physical cluster in a colocation with high availability and a smart caching system designed to keep 'hot' items in an SSD cache, while a massive store was on tier-3 disks. The project included:

Distributed transcoding of the content to a multitude of formats supported by the customer's devices.
Web-ui for the administrator to handle users, API keys and content metadata

News parser (PYMNTS.com) Sysadmin - Backend dev - Frontend dev - Tooling

The main purpose of this project was the automatization of data scraping from multiple news sources.

The data is gathered by polling the sources in a parallelized manner every set amount of time, validated against a set of keywords (with associated per-source weights) and stored in a database.

The sources and keywords can be managed by the users via a web interface; they also decide which matching articles are not useful and tag them as such, every month the weights and keywords get reevaluated based on ‘useless’ articles.

We also have a dashboard displaying metrics, keywords, per-source matches and per-keyword matches.

Multi-language interpreter to extract embedded SQL queries

We had a lot of old applications that had embedded SQL queries and the company had to migrate from Oracle 8 to Oracle 11. To achieve that, we had to analyze ALL the embedded queries so we created an parser for VB6, VB.NET, C#, ASP.NET and Java.

Lab Experience

I maintain a 'lab' to both host my personal projects and learn about new or interesting tech. Some items of note in the lab:

ARM Cluster: load-balancing LXC cluster on multiple physical ARM single-board-computers of (slightly) different architectures (armv6, AArch64) with live container migration using CRIU
Jenkins for automated tests and tricky builds (one of the projects is Android-Windows-Linux)
My physical router (running Debian) is fully deployed from the lab with ansible.
All containers and VMs are fully deployed with ansible.
Backup system (automated ping for offline backups, daily delta and weekly snapshots uploaded to different zones, via different mechanisms)

All of this is monitored with industry-standard tools (telegraf, influx, grafana, email) and also hosts some standard tooling for itself (squid, apt-cacher, git, vpn, proxies, reverse-proxies)

Bonus tracks

Some of my personal projects. You can find more on my blog

Automated book downloading pipeline, fetches, re-formats and pushes books to my kindle.
Wrote a small IOT framework in MicroPython, which I use for my custom devices (all based on esp8266)
- Control my nightlamp with my kindle (shuts it off when I fall asleep)
- Measure ambient humidity/temperature (and plot it in grafana)
- Poor-man's CEC control for my tv to switch input sources automatically
- Control temperature of ambient lighting (warms up over the course of the day)
Reverse engineered the android application to report poorly parked cars provided by the government to automate submissions of people parking in my garage
Proposed a system (and proof-of-concept) to the highway authorities to catch speeding cars in freeways/highways using OpenCV to detect the license plates
Currently writing a set of tools to handle my 3d-printer in better ways (emitting gcode at consistent frequency, cura plugin)
Currently writing a video pipeline to detect and flag motion detection with my home security cameras.