About me / CV

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János Pásztor

Nickname: janoszen
Website: www.janoszen.com
E-mail:
Phone: +43 676 696 6276
Skype: janoszen
Born: 1984-08-16
Nationality: German, Hungarian
Languages: German, Hungarian, English
Location: Vienna, Austria


Table of Contents


Social profiles

Projects, codes: GitHub
Job profile: LinkedIn
Personal: Facebook Twitter

Fields of expertise

  • Development and Operations team management
  • Large scale web systems
  • System-level and web application design
  • Automated Linux deployment
  • Web hosting infrastructures
  • E-mail / newsletter systems
Operating systems: Linux (Gentoo, Debian, Ubuntu)
Web servers: Apache HTTPd, LigHTTPd, nginx, Apache Tomcat
Mail servers: Exim
Databases: MySQL
Automation tools: cfengine
Scripting: Bash, Python
Web development: PHP, Java; JavaScript (+jQuery)
Load balancers: IPVS/LVS
Networking: OSPF, RIP (Quagga)

Career in brief

Developer at IXOLIT New Media Development GmbH

  • PHP and frontend development.
  • Liaison between the operations and the development team.
  • Read more »

Development and operations team leader at DotRoll Kft / DoclerWeb Kft (DoclerHolding group)

  • Management of two acquisitions.
  • Deployment of a GLB DNS.
  • Design of an asynchronous workflow system for system-level deployment of hosting, email and DNS accounts.
  • Design of a OpenVZ container-based hosting solution to allow inclusion of acquired legacy hosting services.
  • Consulting for other Docler projects (eg. LiveJasmin)
  • Read more »

Lead system administrator at DotRoll Kft (DoclerHolding group)

  • Maintenance of the extra.hu hosting service (several 100k sites, HP EVA maintenance, 50+ physical servers).
  • Research and deployment of a scalable hosting service based on custom technology (Hardened Linux, Apache extension development).
  • Research and deployment of a redundant and extremely scalable e-mail service (Exim, OSPF/IPVS load balancing, 54 virtual servers)
  • Stress testing and deployment of LDAP-based DNS infrastructure.
  • Read more »

Developer at Gigamad Kft (DoclerHolding group)

  • Design and development of a used car search engine.
  • Read more »

Developer at Oditech Studio

  • PHP development for clients
  • Introduction of version controlled development
  • Read more »

Charity

Karinthy Frigyes High School

I have been working as a voluntary system administrator for the school for more than 10 years. With other volunteers we fit the school with WIFI coverage for about 1000 USD (700 EUR), built kiosk terminals where students and staff members could log in with their chip card, an e-classbook and much more.

Mediabirodalom startup incubator project

The Mediabirodalom project is a single server to help young Hungarian startups to get their project running. We are currently hosting a blog reader and the crawler engine for it and several smaller projects.


Hobbies

  • Rock climbing / hiking / Klettersteig (viaferrata)
  • Cooking

Professional history in detail

Developer
IXOLIT New Media Development GmbH, Austria
(since december 2011)

As a starter job in Austria, I have mainly focused on frontend development as well as liaising between the operations and development team.

Development and operations team leader
DotRoll Kft / DoclerWeb Kft (DoclerHolding group), Hungary
(january – november 2011)

As the former lead developer left the company, I was charged with the responsibility of leading both the development and the operations team. With a team of 3 developers, 2 sysadmins and one sitebuilder we maintained over a million lines of PHP code, and over hundred virtual and physical servers. I have implemented a new, fully automated release infrastructure and we have deployed a new web interface I had been developing as a side project as lead system administrator, which bridged the gap to our old system, providing a proxy service to it and allowing us to move faster in frontend optimization. After quite a lot of research into HTTP proxies, we also migrated the hosting service behind an nginx proxy to allow faster customer migration from one server to an other by skipping DNS TTL’s. The proxy knew which customer was on which server and was set up to allow 2 minute migrations.

The devops part of the DotRoll team was restructured into the larger DoclerWeb company from early summer to the end of the year. My job was to integrate formerly independent DotRoll into the group’s infrastructure as well as providing technological advice to other teams such as LiveJasmin development.

The group also acquired two domain registrar and hosting companies, that needed to be integrated into the existing systems. As the existing systems couldn’t handle the workload, I designed and lead the implementation of a fully asynchronous work flow system, that provided the necessary components to implement business requirements quickly and with little room for error. This system was among others responsible for the handling of a globally load balanced DNS infrastructure, which consisted of 6 servers across the globe to minimize DNS response times while providing the customers with the ability to edit their DNS settings within seconds.

To maximize customer satisfaction of acquired companies, I designed a web hosting system on OpenVZ basis, that allowed running just about any legacy infrastructure such as Apache with mod_php, suPHP or FastCGI, still separating the customers from each other and providing resource usage control.

Lead system administrator
DotRoll Kft (DoclerHolding group), Hungary
(december 2008 – december 2010)

After running a private server for quite some time I switched jobs to be a system administrator on the now defunct extra.hu free hosting service. The service itself had several hundreds of thousands of sites and there was room for improvement. In the first few months I was alone on the operations job to handle more than 50 servers and one HP EVA 6100 storage solution, but soon became the lead of a team of two. We also had to move the whole service once to a different server room. Afterwards we carried out several improvements on the service, such as regular backups that were available to users, switching from proprietary to installed-from-package Linux systems and implementing vhosting module written in C that replaced the previous RewriteMap script and thus saved almost half the servers for other purposes.

When we started implementing the hosting service, we took the experience gained by operating the extra.hu service and built a system, that was based on standalone webhosts and maintained with cfengine. The host itself was running a grsecurity kernel, that withstood all attempts to crash it by the IT security team. There were also plans and attempts to implement RBAC, but instead we developed a suexec replacement, that allowed us to chroot each and every user into an own chroot while maintaining overbooking capabilities by killing unused FastCGI processes.

As for the domain registration service, we provided several major improvements, such as the OSPF/IPVS loadbalanced frontend solution, an LDAP-based DNS infrastructure and an e-mail solution consisting of 54 mail servers, each having a very specific rule, being – except for the mailstorages – fully redundant and scalable. Despite the rapid growth in e-mails, the latter didn’t need any major restructuring or attention except for the regular software upgrades. There was also research into newsletter servers, which was feature-complete, but was never implemented due to business decisions.

We also assisted in meeting the requirements for the ICANN accreditation, which is necessary to register .com/.net/etc domains directly. The fact, that this was the second company in Hungary to achieve the accreditation adequately describe the amount of work, that had to be done.

Developer
Gigamad Kft (DoclerHolding group), Hungary
(december 2007 – december 2008)

Gigamad was a car search engine, much like mobile.de, but aimed towards the Hungarian market. The owner of the company had a long experience with selling and buying cars, so under his lead we developed a search engine, that handled search queries on over 180 parameters for different vehicles while staying scalable to multiple servers. Later on the site got multiple social parts, such as a forum, a chat and a video section as well.

Developer
Oditech Studio, Hungary
(june 2007-october 2007)

After working for this company for a year as a freelancer, I joined them as an employee. My job mainly was to develop websites, webshops and the likes for clients. One of my merits here was the implementation of version control and separated development servers.