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

Verified Expert  in Engineering

Software Developer

Baia Mare, Maramureș County, Romania
Toptal 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.


RedCapcloud Inc
Git, DevOps, AWS HA, Kubernetes, HAProxy, Containers, AWS NLB, Ansible, AWX
Usability Dynamics
Kibana, Beats, Logstash, Docker, Elasticsearch, MySQL, Cluster
VPSie Inc.
Hosting, KVM, Virtualization, Kubernetes




Preferred Environment

Linux OpenSuSe, RHEL, CentOS, Debian

The most amazing...

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

Work Experience

DevOps Manager

2019 - PRESENT
RedCapcloud Inc
  • Implemented a High Available environment for our pipelines using Jenkins.
  • Converted the whole stack into the containerized environment.
  • Implemented Security Checks and monitoring using ELK stack, Prometheus/Grafana.
  • Implemented Security Checks and monitoring using ELK stack, Prometheus/Grafana.
Technologies: Git, DevOps, AWS HA, Kubernetes, HAProxy, Containers, AWS NLB, Ansible, AWX

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 master-master replication for keeping uptime as long as possible for emergencies.
  • 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 split them into 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 for 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 they 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, Kubernetes

IT Manager

2010 - 2015
  • Deployed Asterisk and OpenSIPs software and configured them to achieve good voice quality during calls (VoIP).
  • Maintained the web server using Nginx and kept the certificates up to date so that users could use them to add credit to their accounts.
  • Administered and maintained a cluster of 3 database servers using master-master replication.
  • 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 solving the tickets while keeping customer satisfaction as high as possible. The personal customer satisfaction rate was 95% while the entire mobile internet team's customer satisfaction was 90%.
  • Deployed a high-speed internet-proxy service for mobile providers and integrated it into the customer mobile network. A few of the largest deployments were at Claro (Puerto Rico), Spring (Kansas City, MI), and Meteor (Ireland).
  • Wrote Bash scripts that would handle large amounts of repetitive tasks.
  • Used 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 that 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 kinds 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 that 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.
  • 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

VPS Migration
A KVM virtual machine migration from one host to another and a necessary update of the client reference in the MySQL database. It also deploys the necessary ebtables rules by running the script required to apply them.
1999 - 2001

Master of Science in Theoretical Chemistry

Babeș-Bolyai University - Cluj-Napoca, Romania

1995 - 1999

Bachelor of Science in Theoretical Chemistry

Babeș-Bolyai University - Cluj-Napoca, Romania


Flannel, libvirt


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


Bash, Python 3, SQL


Linux OpenSuSe, Rkt, AWS HA, OpenSIPs


Continuous Integration (CI), Continuous Deployment, Hosting, DevOps


KVM, Buddy, DigitalOcean, Linux RHEL/CentOS, Linux, Debian Linux, CoreOS, Debian, CentOS, Amazon Web Services (AWS), Windows, WordPress, Docker, Kubernetes, AWS NLB, Quick EMUlator (QEMU)


MySQL Clustering, Amazon S3 (AWS S3), Elasticsearch, Google Cloud, MySQL, DB

Industry Expertise



Clustering, DNS, Galera Cluster, Networks, UDP, Domain DNS Setup, TCP/IP, RHEL, Virtualization, Beats, VoIP, HAProxy, Containers, AWX, VPS, System Administration

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