Keresztes Peter-Zoltan, Software Developer in Baia Mare, Maramureș County, Romania
Keresztes Peter-Zoltan

Software Developer in Baia Mare, Maramureș County, Romania

Member since September 14, 2016
Keresztes is an experienced system administrator and architect who has been working for over 15 years in the field; working in mostly a Linux environment. He prefers quality over quantity, but whenever possible he would prefer to combine the two. Keresztes is a communicative and concise professional who has successfully worked remotely in the past and is looking for challenging and innovative projects to work on in the future.
Keresztes is now available for hire




Baia Mare, Maramureș County, Romania



Preferred Environment

Linux OpenSuSe, RHEL, CentOS, Debian

The most amazing...

...project I have architected is a complete automated VPS hosting service using KVM.


  • Database Administrator

    2015 - PRESENT
    Usability Dynamics
    • Developed SQL queries to get different statistics from the databases.
    • Installed and configured per client multi-node MySQL clusters using Percona XtraDB using master-master replication for keeping uptime as long as possible for emergencies such as one node going down then the other nodes would be able to serve SQL traffic without interruption.
    • Deployed a client-based website built on WordPress using Docker.
    • Configured Elasticsearch clusters for keeping the logs centralized.
    • Used Logstash to convert parsed log files to JSON and splitting them on items before adding them to Elasticsearch.
    • Added Beats to MySQL queries to Elasticsearch for quick and easy access.
    • Generated graphs and created a tool for easy Elasticsearch access, using Kibana.
    Technologies: Kibana, Beats, Logstash, Docker, Elasticsearch, MySQL, Cluster
  • System Architect

    2013 - PRESENT
    VPSie Inc.
    • Wrote the commands and found the necessary software so that we can create a fully automated VPS hosting provider where the customers can go and deploy their own instances and have them automatically configured without the need of human intervention.
    • Developed the templates for the VPS hosting which would be used to deploy the instances required by the customers using KVM.
    • Set up Nginx to host the website and user portal while keeping everything up-to-date with zero downtime.
    • Built a MySQL cluster using Percona XtraDB installed on 3 nodes with master-master replication so that we could keep database connectivity with zero downtime.
    • Worked with a libvirt API to achieve automatic KVM deployments.
    • Set up DNS servers for fast replication so that it could be used by the customers to host domains related to their VPS instances.
    • Developed SQL queries for getting different statistics.
    Technologies: Hosting, KVM, Virtualization
  • IT Manager

    2010 - 2015
    • Deployed Asterisk and OpenSIPs software and configured them to achieve a good voice quality during calls (VoIP).
    • Maintained the web server using Nginx and kept the certificates up to date so that users could use it to add credit to their accounts.
    • Administered and maintained to a cluster of 3 database servers using master-master replication so that if one database node would go down the other nodes would be able to handle the traffic until the down node could be brought back into production state without affecting the customer experience.
    • Examined the VoIP and HTTP traffic so that we could find issues when the traffic acted unexpectedly so that we could tell the developers where the issues were that we were encountering (debugging).
    Technologies: MySQL Clustering, MySQL, NGINX, Apache, VoIP
  • Customer Support Engineer

    2007 - 2010
    • Worked and deployed products in a Linux environment so that the mobile phone providers would be able to provide flawless customer experience.
    • Took on customer tickets of varying priorities. Solved the tickets while keeping the customer satisfaction as high as possible. Personal customer satisfaction rate was 95% while the entire mobile internet team customer satisfaction was 90%.
    • Deployed a high-speed internet-proxy service for mobile providers and integrated it into the customer mobile network. Few of the largest deployments were at Claro (Puerto Rico), Spring (Kansas City, MI), and Meteor (Ireland).
    • Wrote Bash scripts which would handle large amounts or repetitive tasks.
    • Used my in-depth understanding of TCP/IP to explain to our customers what exactly they needed to do in order to get relevant traffic routed to our servers.
    Technologies: Telecommunications, RHEL
  • System Administrator

    2005 - 2006
    Dabove Servizii
    • Set up a server using a SUSE professional version to handle user authentications using a Samba domain controller. Also set up a proxy with the proper ACLs so that users could have access only to relevant sites.
    • Configured the web server to host multiple websites; forums which were related to the company.
    • Set up a server using FreePBX for the call center so that Italian customers could be connected with as little wait time as possible.
    • Designed employee workstations to have all the necessary software while fighting the virus problems these kind of networks are exposed to.
    • Implemented the TCP/IP physical network so that the employees would have no packet-loss issues and so that the network would be secured from the outside.
    Technologies: VoIP
  • System Administrator

    2001 - 2005
    Babeș-Bolyai University
    • Maintained a Linux server which was hosting the university's website and held email accounts for about 2,000 professors and students.
    • Configured Sendmail to provide email accounts to all the professors and students while making sure that the email accounts were spam and virus-free and that no pertinent emails were filtered by the spam checkers and antivirus programs. All this was done with the usage of open-source software to keep things as cheap as possible.
    • Maintained and updated a web server and websites so that we could deliver the proper information as fast as possible using Apache.
    • Maintained a network of 400 PCs running different versions of Windows OS while keeping the network virus-free.
    • Set up and cabled the university so that every office and lab would have a proper internet connection. Conversed with vendors to get the best network appliances and configurations to prevent packet loss (TCP/IP).
    Technologies: Windows, Linux


  • Tools

    NMap, Wireshark, Systemd, NGINX, GitLab, Jenkins, Ansible Tower, Zabbix, VMware, KVM/Qemu, GitHub, Travis CI, Tcpdump, Cluster, Logstash, Kibana, Amazon ECS (Amazon Elastic Container Service), Amazon Virtual Private Cloud (VPC), Apache, Asterisk
  • Languages

    Bash, Python 3, SQL
  • Frameworks

    Linux OpenSuSe, Rkt, AWS HA, OpenSIPs
  • Libraries/APIs

    Flannel, libvirt
  • Paradigms

    Continuous Integration (CI), Continuous Deployment, Hosting
  • Platforms

    KVM, Buddy, DigitalOcean, Linux RHEL/CentOS, Linux, Debian Linux, CoreOS, Debian, CentOS, Amazon Web Services (AWS), Windows, WordPress, Docker
  • Storage

    MySQL Clustering, Amazon S3 (AWS S3), Elasticsearch, Google Cloud, MySQL
  • Other

    Clustering, DNS, Galera Cluster, Networks, UDP, Domain DNS Setup, TCP/IP, RHEL, Virtualization, Beats, VoIP
  • Industry Expertise



  • Master of Science in Theoretical Chemistry
    1999 - 2001
    Babeș-Bolyai University - Cluj-Napoca, Romania
  • Bachelor of Science in Theoretical Chemistry
    1995 - 1999
    Babeș-Bolyai University - Cluj-Napoca, Romania

To view more profiles

Join Toptal
Share it with others