Sergio Barrientos — Linux & Virtualization Engineer

Professional Summary

Linux and Virtualization Engineer responsible for 300+ RHEL servers across distributed datacenters at a BaFin/ECB-supervised European financial institution. Driving RHEL 7/8 → 9 migration programs, automating server lifecycle operations with Ansible + Git pipelines, and delivering applied GenAI initiatives with Azure AI Foundry. Previously managed a fleet of 100+ Linux/Windows servers and led a 5-person operations team for an international Norwegian financial client with strict SLA governance.

Work Experience

Linux and Virtualization Engineer · Deutsche Pfandbriefbank AG

Jul 2025 – Present

Full-time · Hybrid · Madrid, Spain · Regulated financial institution (BaFin/ECB-supervised) · 300+ Linux servers

Fleet Ownership: Part of the Linux infrastructure team responsible for 300+ RHEL production servers across multiple datacenters, ensuring operational continuity for banking-critical workloads under BaFin/ECB regulatory oversight.
RHEL Migration: Leading phased RHEL 7/8 → RHEL 9 migration across 300+ servers; managing Satellite-based provisioning, software distribution, and compliance enforcement with zero unplanned downtime.
Infrastructure as Code: Designed Ansible + Git automation pipelines for server provisioning, configuration drift remediation, and lifecycle operations, eliminating manual runbook steps and enabling peer-reviewed, auditable changes.
High Availability & DR: Operating Pacemaker-based HA clusters and executing disaster-recovery drills across geographically distributed datacenters, maintaining financial-sector continuity requirements.
Application Platform Operations: Deploying and maintaining diverse application stacks across Nginx, Apache HTTP Server, Tomcat, and JBoss/WildFly, including PostgreSQL database administration, SSL/TLS hardening, reverse proxy tuning, and production performance optimization for banking-critical workloads.
Patch & Hardening: Owning end-to-end patching cycles for 300+ servers with compliance controls aligned to BaFin/ECB security requirements; coordinating maintenance windows with application owners to minimize business impact.
Virtualization: Administering VMware vSphere environments for VM provisioning, reconfiguration, capacity planning, and platform lifecycle maintenance.
Applied GenAI: Delivering business AI use cases with Azure AI Foundry. Built document intelligence pipelines for automated data extraction and initiated model fine-tuning workflows for internal process automation.
Stakeholder Consulting: Acting as infrastructure technical consultant for application owners, translating business requirements into delivery plans and managing expectations across cross-functional teams.

Linux Red-Hat Specialist / IT Application Specialist · Sopra Steria

Nov 2023 – Jul 2025

Full-time · Hybrid · Madrid, Spain · Enterprise outsourcing for a Norwegian financial client · 100+ servers

Team Leadership: Led a team of 5 technicians managing 100+ Linux and Windows servers for a Norwegian financial client in a fully English-speaking environment, ensuring SLA targets were consistently met.
Systems Management: Maintained RHEL compliance across 100+ servers using Red Hat Satellite; built Ansible automation for provisioning and configuration management, reducing deployment time from hours to minutes.
Virtualization: Managed VMware vSphere and vCenter environments (cloud + on-prem), handling VM lifecycle operations, snapshot management, and resource capacity optimization.
ITSM Operations: Resolved incidents and managed change operations in ServiceNow within SLA deadlines; maintained structured escalation and knowledge-base documentation for the team.
Active Directory: Administered AD computer object lifecycle, group policies, and Kerberos integration for Linux servers, supporting enterprise identity and access management workflows.

IT Application Specialist · Sopra Steria

Apr 2023 – Jan 2025

Full-time · Madrid, Spain · Multi-technology enterprise support

Delivered advanced technical support across Linux, Windows, and cloud platforms in enterprise production contexts with SLA-driven resolution targets.
Contributed to cloud-transition support initiatives and workplace modernization programs.
Collaborated across global teams in structured escalation and resolution environments.

Internship Trainee · Sopra Steria

Apr 2023 – Jun 2023

Internship · Madrid, Spain

Built foundational skills in incident handling, directory services, and enterprise support workflows within an ITIL-governed service desk.

Technical Skills

Linux Systems RHEL 7 / 8 / 9, Red Hat Satellite, HA Clustering, Pacemaker, LVM, systemd, SELinux, Kickstart Automation & IaC Ansible (playbooks, roles, Execution Environments), Bash scripting, Git workflows, CI/CD pipelines Virtualization VMware vSphere, vCenter, VM lifecycle management, resource optimization App Platforms & Databases Nginx, Apache HTTP Server, Apache Tomcat, JBoss / WildFly, PostgreSQL, SSL/TLS, reverse proxy, application deployment Cloud & AI Microsoft Azure, Azure AI Foundry, Document Intelligence, LLM fine-tuning, RAG pipelines Monitoring & ITSM CheckMK, ServiceNow (incident/change/CMDB), ITIL processes Directory Services Active Directory, Kerberos / keytab integration, AD group mapping for Linux

Certifications & Education

RHCSA — Red Hat Certified System Administrator Sep 2024

RHCE — Red Hat Certified Engineer Planned 2026

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

Languages

Spanish Native

English Professional working proficiency

French Basic

Portfolio & Projects

sergiiob.dev — Engineering portfolio with 40+ technical case studies in infrastructure automation, RHEL lifecycle management, applied AI integration, and platform operations. Each post follows a structured format: situation, issue, solution, usage context, and delivery impact.