Serhii Ivanov 🇺🇦/🇵🇱 (@s3rj1k)
93 karma
Senior Software Developer (Golang)
Cracow
Per Aspera ad Astra
About
Senior Golang Developer with DevOps Expertise and Exceptional Soft Skills for Dynamic Team Environments
Languages
English ⋅ Proficient
Ukranian ⋅ Native Speaker
Russian ⋅ Native Speaker
Skills
Git ⋅ Advanced
Golang ⋅ Advanced
Gin ⋅ Advanced
Java ⋅ Intermediate
PHP ⋅ Beginner
Python ⋅ Intermediate
AWK ⋅ Advanced
Bash ⋅ Advanced
Linux ⋅ Advanced
Kubernetes ⋅ Advanced
Kubernetes Operators ⋅ Advanced
Docker ⋅ Advanced
Ironic ⋅ Advanced
PostgreSQL ⋅ Intermediate
MySQL ⋅ Intermediate
Clickhouse ⋅ Intermediate
Redis ⋅ Intermediate
Neo4j ⋅ Beginner
Kafka ⋅ Intermediate
SaltStack ⋅ Advanced
Chrome CDP ⋅ Intermediate
Fuse ⋅ Advanced
Github Actions ⋅ Intermediate
Bamboo ⋅ Intermediate
Projects
go-fanotify
Golang fanotify example
MakefileGo
dhcp-relay
DHCPv4-Relay (opinionated Golang implementation).
MakefileGoDockerfile
baremetal-operator
Bare metal host provisioning integration for Kubernetes
SmartyPythonDockerfileGoMakefileShell
nginx-js-challenge
JS Challenge (like Cloudflare) service that uses nginx auth_request_module.
MakefileGo
jrpc2
Golang JSON-RPC 2.0 over HTTP Service Library
GoMakefile
validator
This package provides a framework for writing validations for Go applications.
GoMakefile
Experience
Software packaging expert
SignalWire linkedin.com
Jun 2018 to Present ⋅ Remote (side-project)
Software packaging expert (DEB, RPM), working on #1 open-source communications platform in the world on my own free time. Maintenance of build systems that utilize Autotools, Make, CMake. Packaging software for Debian and Redhat based Linux distributions. Maintenance of CI/CD workflows using GitHub Actions. Facilitation of partial migration from Bamboo to GitHub Actions.
- Build systems (Make, CMake) and distribution of built packages (DEB, RPM)
Senior Software Developer
Mirantis linkedin.com
Aug 2020 to Dec 2023 ⋅ Remote
Developing and managing Kubernetes operators and ClusterAPI providers (Kubebuilder, Operator SDK, Client-Go) that handle BareMetal server provisioning and life-cycle management (metal3.io/baremetal-operator, dnsmasq-operator, artifacts-controller). Developed iPXE edge controller that bridges the integration gap between Kubernetes and OpenStack Ironic. Developed DHCPv4 Relay in pure Golang tailored specifically to dynamic environments such as Kubernetes clusters. Enhanced system scalability, performance, and robustness through continuous improvements and code reviews and effectively solved BareMetal servers provisioning performance issues in huge Kubernetes clusters that increased the provisioning performance up to 10x. Collaborated closely with system engineers and developers to address complex system requirements. Actively participated in the open source community, contributing to various related projects (Metal3.io, OpenStack).
- Kubernetes operators for Kubernetes on BareMetal Servers
Software Engineer (Golang) / Team Lead
Internet Invest Ltd.
Jul 2017 to Aug 2020 ⋅ Ukraine, Kyiv
Team leadership, project coordination, and mentoring junior staff. Developing back-end infrastructure-related services using Golang with some front-end: - Fanotify-based file modification monitoring for Linux containers running on the host node. - Repackaging PHP (pre 7.x) packages for simultaneous mod_apache use on Debian. - Custom L7 (and L2/L3) DDoS protection using Nginx, an image captcha server, JS hash challenge, and a distributed netfilter ban list. - Distributed TLS certificate storage using Golang FUSE filesystem and alternative implementation using Nginx NJS. - Oversees the development of an in-house container backup solution that uses file-level snapshots. - WebUI for container backup solution using Gin, Semantic UI, and PostgreSQL. - PoC system level (PID1) containers control using opencontainers/runc and alternative implementation using LXC Golang bindings. - Network hooks for LXC/LXD and Libvirt for advanced networking setups (TC rules, policy routing, netfilter rules, VxLAN, MAC-Spoof protection). - API, WebUI, and CLI for taking website screenshots using CDP and headless Chromium, with perceptual hashing algorithms for change detection and reporting. - JSON-RPC over HTTP framework with in-house validation framework for PHP Symphony-based client integration. - PoC Libvirt control plane using JSON-RPC over HTTP framework. - JSON-RPC over HTTP API for iLO (HPE BMC) access over NAT (additional level of security). - Custom Cgroups monitoring agent and receiver for Linux containers with Clickhouse as time-series storage and dynamic Grafana dashboards. - Linux container management control plane based on JSON-RPC over HTTP, running on container host nodes and communicating with container agent via execv pipes.
- Team lead, Mentor, Golang developer
DevOps Engineer
Internet Invest Ltd.
May 2016 to Aug 2020 ⋅ Ukraine, Kyiv
BareMetal server, Linux Containers provisioning and maintenance using custom solution and SaltStack leveraging Salt-SSH with security patched SSH server on container side and Salt in Master-Minion mode for BareMetal servers.
- SaltStack, automation
System Administrator
Internet Invest Ltd.
Apr 2015 to May 2016 ⋅ Ukraine, Kyiv
Administration (including physical setup), provisioning, and monitoring of the network infrastructure and equipment, BareMetal servers, services, and data transport channels using Zabbix and Nagios. Customer consultation and extensive technical support including tailoring Linux Containers based hosting solutions to meet the various customer requirements: managed Nginx, Apache, PHP, MariaDB/MySQL, Redis, Memcached, Sphinx, Elasticsearch, Varnish, and other VPS-related software.
- Customer support (on-call)
System Administrator
IT Service Group
Jun 2014 to Mar 2015 ⋅ Ukraine, Kyiv
Customer support, Workstation and Server maintenance (Microsoft based solutions).
- Customer support
System Administrator
Siversk professional lyceum
Jun 2007 to Jun 2014 ⋅ Siversk, Ukraine
Setup and maintenance of Microsoft Windows based workstations, basic intranet infrastructure management.
- System administration
System Administrator
"Severskoe Televidenie" Ltd.
Jun 2012 to Jan 2014 ⋅ Siversk, Ukraine
Setup and maintenance/administration of FreeBSD and Linux based servers for traffic billing, routing and media sharing.
- System administration
Education
Ukrainian Engineering and Pedagogical Academy of Bakhmut (Artemivsk)
Master's degree, Telecommunications engineer, teacher
Dec 2007 to Dec 2013
Certificates
English Level C2 PROFICIENT efset.org
EF SET Certificate
Feb 26, 2023
CN100: Docker Containerization Essentials certification.mirantis.com
Mirantis Training
Feb 25, 2023
CN110: Docker Swarm Application Essentials certification.mirantis.com
Mirantis Training
Feb 27, 2023
CN120: Kubernetes Application Essentials certification.mirantis.com
Mirantis Training
Feb 28, 2023
CN220: Kubernetes Operations certification.mirantis.com
Mirantis Training
Mar 7, 2023
CN230: Kubernetes Native Application Development certification.mirantis.com
Mirantis Training
Mar 7, 2023
CN320: Advanced Kubernetes Operations certification.mirantis.com
Mirantis Training
Mar 8, 2023
CN330: Advanced Kubernetes Security certification.mirantis.com
Mirantis Training
Mar 9, 2023