Олександр

Oleksandr Sterenchuk
Junior SRE / DevOps Engineer
Kropyvnytskyi, Ukraine · [відкрити контакти](див. вище в блоці «контактна інформація») · [відкрити контакти](див. вище в блоці «контактна інформація») · github.com/Sterenchuk · [відкрити контакти](див. вище в блоці «контактна інформація») ·
home.sansesdevelopment.uk
Junior DevOps/SRE engineer with a BSc in Computer Science (average 96/100) and a production backend background (NestJS, Express.js,
PostgreSQL, MongoDB, Redis; 7-month backend internship at Onix). Runs a multi-node home lab (Ubuntu, Docker, k3s, Tailscale, Cloudflare
Zero Trust) and deploys production-style stacks end to end: reverse proxy, tunnels, databases, load balancing, audit and load testing.
Cisco-certified in networking and security; comfortable with DHCP, DNS and switching.
CORE DEVOPS SKILLS
Containers & Orchestration: Docker · Docker Compose multi-project stacks · Kubernetes (k3s) · namespaces
Cloud & CI/CD: AWS (EC2, S3, RDS) · AWS CLI · S3-compatible storage (Garage) · GitHub Actions · CI processes in production (Onix) · Git
Monitoring & Reliability: k6 load/stress testing (5,000 req/s) · Uptime Kuma · Dozzle · alerting design · backup/restore drills
Networking: DHCP · DNS · switching · static addressing · Tailscale · Cloudflare Tunnel / Zero Trust · Traefik v3 · Nginx load balancing ·
nmap · Packet Tracer
Databases: PostgreSQL · MongoDB · Redis · replication concepts · per-app users and roles · Prisma
Linux & Security: Ubuntu 24.04 · bash · SSH keys · ufw · fail2ban · unattended-upgrades · xrdp · JWT/OAuth2 · RBAC · OWASP ASVS
Languages: TypeScript/Node.js, NestJS, Express.js · Python and Go (learning) · C++ · Rust (basic) · REST, GraphQL, WebSockets
KEY DEVOPS PROJECTS
Home Lab: k3s Cluster & Self-Hosted Platform GitHub → Live →
Ubuntu · k3s · Docker Compose · Traefik · Cloudflare Zero Trust · Tailscale · Postgres · Homepage dashboard
• Built a multi-node home lab (Lenovo master node plus older machines for testing and storage) with a hardened baseline: SSH keys, ufw,
fail2ban, Tailscale, automatic updates
• Automated node setup with a bootstrap script repository (common hardening plus per-role setup) so new machines join consistently
• Exposed services publicly through Cloudflare Zero Trust tunnels and Traefik v3 on a shared Docker network; fixed DNS collisions between
Compose projects with explicit network aliases
• Solved unstable addressing on a DHCP-only home router with local static IPs and Tailscale as the stable node network; running a
Homepage dashboard on k3s, adding Uptime Kuma, Dozzle, shared Postgres with replicas, NAS and an AWS EC2 node
Secure Voting & Survey Platform (Bachelor's thesis) GitHub →
NestJS · Next.js · PostgreSQL · MongoDB · Redis · Docker · Nginx · Traefik · Cloudflare Tunnel · k6
• Deployed a multi-service stack (3 NestJS replicas behind Nginx, workers, Postgres, Mongo audit chain, Redis) with Docker Compose,
Traefik v3 and Cloudflare Tunnel; designed to OWASP ASVS and EU CM/Rec(2017)5
• Load-tested with k6 up to 5,000 req/s (50,000 seeded users); fixed worker retry loops, Redis sequence gaps and MongoDB role privilege
gaps
• Diagnosed infrastructure failures: Traefik Docker API version mismatch, Cloudflare hostname scheme mismatch and service DNS collisions
Cloud File Storage (AWS)
NestJS · TypeORM · AWS EC2 · S3 · RDS · Docker · Garage S3
• Built a Drive-style storage backend, moving from a local-first design to AWS (EC2 compute, S3 object storage, RDS); large-file uploads up
to 5 GB via streaming, multipart and presigned URLs
• Prepared a Cloudflare-ready Compose stack (Postgres 17, Garage S3, NestJS API); evaluated Prisma v7 vs TypeORM for Docker and
documented the tradeoffs

EXPERIENCE
Backend Developer Intern — Onix Nov 2025 – May 2026
• Delivered backend features in a production NestJS codebase: REST API endpoints and PostgreSQL schema design; worked with
Docker-based deployment and CI processes, resolving issues via a ticketing system
• Took part in code review, Git workflow and Agile ceremonies; collaborated with senior engineers on delivery estimates and technical
decisions
Backend Contributor (API Integration) — AI Automation Solutions Startup 2025
• Implemented and tested API request handling for automation pipelines, with error handling and response parsing, working directly with the
founding team
Freelance Backend Developer — Independent 2024
• Built a website for a local building-materials business on Express.js, owning backend/server logic
IT Teacher — Inter-web IT School Feb 2024 – May 2025
• Taught HTML, CSS, JavaScript and full-stack fundamentals to beginners; mentored debugging workflows and client-server concepts
EDUCATION
BSc Computer Science — Central Ukrainian State University · 2022 – 2026 (Graduated) · Avg 96/100 · Group Starosta · Thesis: Secure
Electronic Voting System
DILLUGIS 24 — Project Management & Agile · Germany · 5 ECTS · 93/100
CERTIFICATIONS & AWARDS
Cisco – Ethical Hacker · Cisco – Networking with Packet Tracer · Cisco – IoT Fundamentals · IELTS Academic C1 (2026) · KPI Hackathon –
3rd Place · TechForAll Hackathon – 3rd Place (2025)