Athanasios is available for hire

Athanasios Voutsadakis

Verified Expert in Engineering

Software Developer

London, United Kingdom

Toptal member since February 4, 2020

Expertise

Git Python Bash Linux GitHub Docker Continuous Delivery (CD)Amazon Web Services (AWS)Terraform Prometheus DevOps Redis Django Jenkins Kibana Cloud Foundry

Bio

Athanasios has worked in many capacities, including Python developer, DevOps, and site reliability engineer (SRE) for startups and large organizations. Recently, he served as an SRE at a government digital service where he managed and scaled the infrastructure of GOV.UK Notify and helped build common tools and services that are used by many teams within the organization.

Portfolio

Government Digital Service

Amazon Web Services (AWS), Bash, Terraform, AWS Fargate...

Critical Start, Inc.

Amazon Web Services (AWS), Amazon Elastic Container Service (ECS)...

Government Digital Service

Amazon Web Services (AWS), Git, Python, Bash, Redis, Cloud Foundry...

Experience

Linux - 12 years DevOps - 9 years Docker - 7 years Amazon Web Services (AWS) - 7 years Terraform - 7 years System Design - 7 years CI/CD Pipelines - 7 years Scaling - 7 years

Availability

Full-time

Preferred Environment

Git, Python, Go, Bash, Linux, Vim Text Editor, Terraform, GitHub

The most amazing...

...thing I've done was to improve the scalability of the GOV.UK Notify application by enabling them to predict traffic surges.

Work Experience

Site Reliablity Engineer

2020 - 2023

Government Digital Service

Designed, orchestrated, and implemented the foundations for migrating the entire GOV.UK Notify service to an AWS ECS-based infrastructure.
Designed and implemented traffic migration strategies, aiming for minimal interruption to both users and developers while moving >1k reqs/sec and 3 TB PostgreSQL database to the new infrastructure.
Designed and implemented gradual traffic migration from custom Nginx proxies to Terraform-managed Cloudfront distributions while working closely with our users to ensure their integrations with our service were not interrupted.
Improved performance of the GOV.UK Notify team's FTP application by two orders of magnitude.
Built the gov.uk/alerts infrastructure using a combination of Cloudfront and Lambda@Edge.
Used a combination of AWS AMI Builder and Concourse to build, patch and roll airgapped AWS instances every night.

Technologies: Amazon Web Services (AWS), Bash, Terraform, AWS Fargate, Amazon Elastic Container Service (ECS), Concourse CI, PostgreSQL, Python, Amazon CloudFront CDN, AWS Lambda, Lambda@Edge, Continuous Delivery (CD), Docker, Git, System Design, Scaling, DevOps, CI/CD Pipelines, GitHub

DevOps Engineer

2020 - 2020

Critical Start, Inc.

Created a Python-based container scheduler to ensure the applications were running reliably on the clients.
Maintained and refactored the existing terraform codebase to accommodate the evolving needs of the company.
Integrated AWS services with an external OAuth provider for increased ease of user management across products.

Technologies: Amazon Web Services (AWS), Amazon Elastic Container Service (ECS), Amazon Elastic Block Store (EBS), Terraform, Amazon EC2, Amazon S3 (AWS S3), Load Balancers, Bash, Python, Docker, Git, DevOps, CI/CD Pipelines, GitHub

Senior Site Reliability Engineer

2017 - 2019

Government Digital Service

Managed and scaled the infrastructure of GOV.UK Notify, allowing them to handle 60 times more traffic.
Developed and maintained the autoscaling solution for GOV.UK Notify, which allowed them to scale proactively.
Organized and ran Game Days for GOV.UK Notify to build the team's confidence in supporting the infrastructure.
Collaborated with other SREs across to migrate GOV.UK Verify to a modern, cloud-based platform, reducing costs by six times.

Technologies: Amazon Web Services (AWS), Git, Python, Bash, Redis, Cloud Foundry, Concourse CI, Terraform, Scaling, System Design, Linux, Continuous Delivery (CD), Kibana, Elasticsearch, Docker, Prometheus, Jenkins, DevOps, Amazon Elastic Container Service (ECS), CI/CD Pipelines, GitHub

Software Engineer

2016 - 2017

Streetlife

Discovered and fixed bottlenecks in the code, reducing the runtime of the test suite by 40%.
Collaborated closely with the Android and iOS developers to design and implement new APIs.
Created and maintained Jira boards for back-end and front-end teams.

Technologies: Git, Python, Django, GitHub

Platform Engineer

2014 - 2016

BBC

Designed, prototyped, and developed a system that allowed developers to ship code from cloud-based CI systems to the on-premises platform.
Migrated from Red Hat 5 to Red Hat 6 all the on-premises servers across four environments.
Upgraded a large on-premises Confluence installation from 3.4.9 to 5.5.6.

Technologies: Git, Python, Bash, Scaling, System Design, Linux, Jenkins, RHEL, DevOps, Docker, CI/CD Pipelines, GitHub

Software Engineer

2013 - 2014

Migreat

Implemented a search functionality from scratch, writing both the front-end and back-end code and introducing Elasticsearch to the company.
Designed the search functionality's architecture, including indexes, documents to be searched for, and index updates.
Increased test coverage of the code and improved deployment reliability.

Technologies: Git, Python, Redis, Knockout (Knockout.js), Neo4j, Elasticsearch, Django, GitHub

Experience

GOV.UK Notify Autoscaler

https://github.com/alphagov/notifications-paas-autoscaler/

A highly available Python-based application running in Cloud Foundry that is used to scale GOV.UK Notify services according to existing or upcoming traffic. It uses various signals and can independently scale different applications based on different rules.

Gofind

https://gitlab.com/sakis/gofind

Gofind is a text-searching utility written in Go. The project reproduced popular text-searching tools like the Silver Searcher or Ripgrep, for example, with the intent to experiment with and learn Go.

Site for Tracking Supermarket Prices

https://pricewatcher.gr/en

A Django and PostgreSQL site for tracking prices on the three biggest supermarkets in Greece by scraping their eshops once per day.

Technologies used: Django, PostgreSQL, Redis, Prometheus, Grafana, Cloudflare, Caddy, Terraform, Docker, Playwright, Tailscale

Can I Be Loud?

https://canibeloud.com

An open-source Rust-based website that answers the question" Can I be loud?" based on the user's time zone.
Its primary purpose is to serve as a playground and experimentation to learn Rust.
Technologies used: Actix.rs, Docker, Terraform, Cloudflare, Caddy

Education

2006 - 2012

Bachelor's Degree in Informatics and Communications

Technological Educational Institute (TEI) of Central Macedonia - Greece

Skills

Tools

Git, Terraform, GitHub, Vim Text Editor, Jenkins, Concourse CI, Kibana, Amazon Elastic Container Service (ECS), Amazon Elastic Block Store (EBS), AWS Fargate, Amazon CloudFront CDN, Caddy Server

Languages

Python, Bash, Go, Rust

Paradigms

Continuous Delivery (CD), DevOps

Platforms

Docker, Linux, Amazon Web Services (AWS), Amazon EC2, AWS Lambda

Frameworks

Django, Knockout (Knockout.js)

Storage

Redis, Elasticsearch, Neo4j, Amazon S3 (AWS S3), PostgreSQL, Databases

Other

Scaling, System Design, CI/CD Pipelines, Prometheus, Lambda@Edge, RHEL, Cloud Foundry, Load Balancers, Networks, Programming, Algorithms, Data Structures, Evolutionary Computation, Cloudflare

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