Sergio Barrientos - Linux Platform Engineer

Professional Summary

Linux platform engineer with experience supporting enterprise systems in banking and railway environments. Currently part of the team responsible for a 300+ server RHEL estate at a BaFin/ECB-supervised bank, working across lifecycle management, patching, automation, VMware, monitoring, and high availability. Outside the core role, I run and benchmark local LLMs on Intel, AMD, and RK3588 hardware and build AI-enabled applications. I bring production Linux operations together with practical experimentation in local inference and applied AI.

Work Experience

Linux and Virtualization Engineer | Deutsche Pfandbriefbank AG

Jul 2025 - Present

Full-time | Hybrid | Madrid, Spain | BaFin/ECB-supervised bank | 300+ server estate

Linux platform operations: Work within the infrastructure team supporting a 300+ server RHEL estate across distributed datacenters and banking-critical workloads.
RHEL modernization: Lead the bank's RHEL 8 to 9 migration project, coordinating the phased technical work and using Red Hat Satellite for provisioning, software distribution, patching, and lifecycle management.
Automation: Build and maintain Ansible playbooks and Git-based workflows for server deployment, controlled infrastructure changes, and reproducible configuration.
Reliability and security: Support hardening and patching cycles, CheckMK monitoring, high-availability clusters, disaster-recovery activities, and VMware vSphere operations.
Application support: Work with Application Owners on Linux requirements and troubleshoot services including Nginx, Apache, Tomcat, JBoss, and PostgreSQL.
Applied GenAI: Contribute to internal exploration and prototypes using Azure AI Foundry and Document Intelligence for document-processing and automation use cases.

IT Application Specialist / Linux System Administrator | Sopra Steria

Apr 2023 - Jul 2025

Internship followed by full-time role | Hybrid | Madrid, Spain | Norwegian railway-sector client | 100+ servers

Technical coordination: Coordinated a five-person team supporting, maintaining, and patching a critical application environment spanning more than 100 Linux and Windows servers.
Linux support: Progressed from an internship into a full-time application support role and later a Linux-focused assignment, troubleshooting Red Hat Linux, Windows, and Azure environments.
Automation: Used Ansible to automate repeatable administration and deployment tasks and supported RHEL lifecycle activities with Red Hat Satellite.
Enterprise operations: Managed incidents, requests, and controlled changes through ServiceNow within an ITIL-aligned support model.
Identity and collaboration: Supported Active Directory, Kerberos, Entra ID, Intune, and Exchange while working in English with a Norwegian client.

Technical Skills

Linux / RHEL RHEL 7/8/9, Red Hat Satellite, LVM, systemd, SELinux, Kickstart, HA/DR, performance tuning Automation / IaC Ansible, Bash scripting, Git-based workflows, repeatable infrastructure configuration AI Infrastructure llama.cpp, GGUF quantization, Intel SYCL, AMD ROCm, RK3588 edge inference, KV-cache tuning, concurrency testing, local LLM benchmarking Platforms / Services VMware vSphere/vCenter, Nginx, Apache HTTP Server, Tomcat, JBoss Web Server, PostgreSQL, SSL/TLS Cloud / GenAI Microsoft Azure, Azure AI Foundry, Document Intelligence, LLM prototyping, Firebase Operations CheckMK, ServiceNow, Active Directory, Kerberos integration, ITIL, change management

Selected Projects

IntelliAuto: Published Kotlin/Firebase vehicle-management app with offline storage, ML Kit OCR, maintenance workflows, and an AI assistant.
IntelliFlow: Privacy-focused personal-finance app with offline-first storage, cloud sync, projections, and AI-generated spending insights.
Engineering portfolio: Reproducible local-LLM work across llama.cpp, GGUF, Intel SYCL, AMD ROCm, RK3588, KV-cache tuning, concurrency, and power efficiency.

Certifications & Education

RHCSA - Red Hat Certified System Administrator Sep 2024

Technician in Computer Systems and Networks Administration Jun 2023 | Madrid, Spain

Languages

Spanish: Native English: Professional working proficiency