Janos Lenart, Developer in Manchester, United Kingdom
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Janos Lenart

Verified Expert  in Engineering

Site Reliability Engineering (SRE) Developer

Manchester, United Kingdom

Toptal member since September 11, 2017

Bio

Janos is an ex-Googler who builds, fixes, and teaches various technologies. He specializes in Linux, clusters (especially Kubernetes), cloud technologies, distributed systems, big data, including database design and clustering, programming in C/C++ and Go.

Portfolio

lenart.io
Kubernetes, Google Cloud Platform (GCP), Terraform, Helm, Docker, Linux, Debian...
Debian
Debian, Linux, C, C++, Bash, AutoTools, Git, dpkg, Kubernetes, GNU Make, Perl...
Google, Inc.
Go, C++, Python, Distributed Systems Development, MySQL Clustering, Borg, Blaze...

Experience

Availability

Part-time

Preferred Environment

Debian Linux, Kubernetes, Google Cloud Platform (GCP)

The most amazing...

...infrastructure I've worked with is the single largest cluster on the planet.

Work Experience

Owner

2016 - PRESENT
lenart.io
  • Trained over a thousand professionals on cloud technologies.
  • Designed, built, troubleshot, and fixed dozens of Kubernetes clusters.
  • Communicated with spacecraft on another planet, and have software running on the International Space Station.
Technologies: Kubernetes, Google Cloud Platform (GCP), Terraform, Helm, Docker, Linux, Debian, Bash, C++, Git, Python, Ubuntu, PostgreSQL, Go, Lua, Debian Linux, Ubuntu Linux, MySQL, Google Container Engine, Standard Template Library (STL), Concurrent Programming, Software Development, DevOps, NGINX, Continuous Integration (CI), Continuous Delivery (CD), Cloud Infrastructure, Site Reliability Engineering (SRE), OAuth, Infrastructure as Code (IaC), OpenID, Cloud, Cloud Architecture, Distributed Systems Development, GNU Make, Amazon EC2, Amazon Web Services (AWS), Amazon Virtual Private Cloud (VPC)

Developer

2000 - PRESENT
Debian
  • Packaged and maintained the official Kubernetes packages for Debian Linux.
  • Updated and maintained the tar package (a core Linux tool, and one of the few essential packages in Debian).
  • Onboarded and mentored new Debian maintainers, working as an application manager.
Technologies: Debian, Linux, C, C++, Bash, AutoTools, Git, dpkg, Kubernetes, GNU Make, Perl, Software Development, Debian Linux, Docker

Site Reliability Engineer

2013 - 2016
Google, Inc.
  • Built automation for highly reliable (4 9s) MySQL database clusters of thousands of computers, providing the back end for services like YouTube.
  • Designed and maintained backup, monitoring, scaling, and provisioning systems.
  • Served as an on-call engineer for mission-critical database back ends.
  • Interviewed engineer candidates over the phone and on-site.
Technologies: Go, C++, Python, Distributed Systems Development, MySQL Clustering, Borg, Blaze, Vitess, Linux, Debian, Bash, C, Git, Ubuntu, Flask, Debian Linux, Ubuntu Linux, MySQL, Standard Template Library (STL), Concurrent Programming, Software Development, DevOps, Continuous Integration (CI), Continuous Delivery (CD), Cloud Infrastructure, Site Reliability Engineering (SRE), Infrastructure as Code (IaC), Cloud, Cloud Architecture

Associate Lecturer

2007 - 2011
Eötvös Loránd University
  • Taught C++, networking, Linux system administration, and mathematics.
  • Managed Linux servers for the ELTE Institute of Mathematics.
  • Conducted examinations for undergraduate students on various topics.
Technologies: Mathematics, Computer Science, Postfix, Exim4, Dovecot, NFS, Samba, RAID, Linux, Debian, C, C++, PostgreSQL, Debian Linux, MySQL, Standard Template Library (STL), Software Development, Bash, GNU Make

Terminal for Kubernetes Dashboard

https://github.com/kubernetes/dashboard/pull/1939
Kubernetes is the leading technology for container orchestration. Kubernetes dashboard is the de facto UI used with it. I've added the feature that lets you execute shells in the containers from that UI.

Private GKE Cluster Support for Terraform

https://github.com/hashicorp/terraform-provider-google/pull/1250
I implemented support for private GKE clusters in the GCP Terraform provider; it is now merged into a mainline.
I was working on a larger project for a medical support organization and this was a side project. They required GKE provisioned with Terraform and no external IPs. Private clusters were in beta at the time and Terraform did not support them yet.

GCP Cloud DNS Support for acme.sh

https://github.com/acmesh-official/acme.sh/pull/1623
acme.sh automates the issuance and renewal of X.509 certificates (SSL/TLS/HTTPS) using LetsEncrypt. This contribution added the Google Cloud DNS validation back end.
I wrote acme.sh in pure shell which makes it a preferable solution in some environments.
2004 - 2009

Bachelor of Science Degree in Computer Science

Eötvös Loránd University - Budapest, Hungary

1999 - 2004

Professional Degree in Software Engineering

John von Neumann Technology College - Hungary

DECEMBER 2018 - DECEMBER 2020

Certified Cloud Architect

Google

Libraries/APIs

OpenID, Standard Template Library (STL)

Tools

GNU Make, Postfix, AutoTools, Git, Amazon Virtual Private Cloud (VPC), Terraform, NGINX, Helm, Exim4, Google Kubernetes Engine (GKE)

Languages

Bash, Python, Go, Lua, C, C++, Perl

Paradigms

DevOps, Continuous Integration (CI), Continuous Delivery (CD), Concurrent Programming, Samba

Platforms

Debian Linux, Ubuntu Linux, Kubernetes, Google Cloud Platform (GCP), Linux, Docker, Debian, Ubuntu, Amazon EC2, Amazon Web Services (AWS)

Storage

MySQL, MySQL Clustering, PostgreSQL

Frameworks

Flask

Other

Site Reliability Engineering (SRE), Infrastructure as Code (IaC), Cloud, Cloud Architecture, Mathematics, Computer Science, Distributed Systems Development, Vitess, RAID, dpkg, Google Container Engine, Software Development, Cloud Infrastructure, OAuth, Borg, Dovecot, NFS, Blaze

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