Linux Systems Administrator Senior Principal

Job Description Summary

We are seeking a Senior Linux Engineer to support enterprise Infrastructure Management and Compliance operations. This role combines hands-on Red Hat Enterprise Linux (RHEL) system administration with security hardening, compliance remediation, and infrastructure automation. The ideal candidate is a proactive problem solver, communicates clearly, and documents processes well, partnering closely with project/team leadership to keep systems compliant and operations running smoothly.

How a Linux Systems Administrator Senior Principal Will Make an Impact

System Administration & Operations

• Provide system administration support for Linux operating systems including installing software, applying patches, managing file systems, monitoring performance, and troubleshooting alerts from monitoring tools
• Configure and troubleshoot RHEL 9 systems, resolving issues associated with the operating system, servers, hardware, and applications software; perform system failure analysis and recovery
• Responsible for daily monitoring of interface programs between multiple enterprise systems; review daily logs and ensure successful completion
• Perform incremental and full cold backups/patching
• Provide performance metrics and usage charts, including CPU usage, disk usage, and network uptime for Linux servers
• Provide general maintenance, upgrades, and new installation of servers; coordinate with data center personnel to execute

Security & Compliance

• Responsible for DoW Linux Security Technical Implementation Guides (STIGs)
• Remediate security findings identified through ACAS/Tenable reports and OpenSCAP scans by performing hands-on system patching, configuration updates, and service hardening on RHEL 9 systems
• Configure and maintain host-based firewalls (firewalld/iptables) and audit daemon logging (auditd) in compliance with DoW auditing requirements
• Develop, implement, and document technical mitigation strategies and POA&Ms for Linux vulnerabilities that cannot be immediately fixed
• Compile technical evidence, OpenSCAP evaluation reports, and configuration artifacts for CORA inspection teams

Automation & Infrastructure as Code

• Develop and maintain automation and scripted deployment solutions to streamline system provisioning, configuration management, and compliance validation, reducing manual effort and speeding up operations
• Utilize package management tools in GIT or local repositories to deploy security errata and software updates across air-gapped or restricted networks
• Be familiar with the operations of Ansible and Terraform to work with IaC engineers establishing standardized deployments.

Documentation & Team Collaboration

• Responsible for creating and/or maintaining standard operating procedures for the Linux documentation library
• Document and generate business processes for day-to-day and emergency support procedures, with strong written and verbal communication
• Coordinate with project and team leadership to meet deadlines and objectives; capable of delivering training sessions as needed
• Present ideas clearly in team meetings and project-level discussions

What You'll Need to Succeed

Education/Experience Required:

• Technical Training, Certification(s) or Degree
• 8+ years of demonstrated experience administering RHEL 8/9 servers
• Bachelor's degree in information technology, computer science, or related technical discipline preferred
• Secret Security Clearance

Required Experience:

• Direct experience in Linux system administration, CLI operations, user management, and package patching
• Hands-on experience configuring and troubleshooting RHEL 9 systems
• Experience handling NFS, CIFS, and SMB permissions
• Hands-on experience applying DISA STIGs to RHEL systems using SCAP Compliance Checker (SCC) or OpenSCAP
• Experience reviewing ACAS/Tenable vulnerability reports and executing Linux-specific remediation
• Understanding of PKI certificate installation and PAM/SSSD authentication integration

Required Technical Skills:

• Strong Linux administration skills with knowledge of enterprise network architectures
• Experience developing automation and scripted deployments to improve operational efficiency
• Skilled in scripting for automation (Bash, Python)
• Solid understanding of Linux internals (system calls, file systems, processes)
• Working knowledge of TCP/IP and related protocols (HTTP, FTP, NFS)
• Excellent problem-solving, analytical, and decision-making skills
• Strong verbal communication and documentation abilities
• Strong organizational, collaborative, and team-oriented mindset

Desired Skills:

• Experience with Ansible for configuration management and automation
• Experience with Terraform for infrastructure as code
• Experience using PowerShell for task automation
• Experience with Red Hat Satellite Server for centralized lifecycle and errata management
• Experience preparing Linux systems for DoD Cyber Defense Command (DCDC) Cyber Operational Risk Assessments (CORA)
• Red Hat Certified System Administrator (RHCSA) or Red Hat Certified Engineer (RHCE)

GDIT IS YOUR PLACE
At GDIT, the mission is our purpose, and our people are at the center of everything we do.

• Growth: AI-powered career tool that identifies career steps and learning opportunities
• Support: An internal mobility team focused on helping you achieve your career goals
• Rewards: Comprehensive benefits and wellness packages, 401K with company match, and competitive pay and paid time off
• Flexibility: Full-flex work week to own your priorities at work and at home
• Community: Award-winning culture of innovation and a military-friendly workplace

OWN YOUR OPPORTUNITY
Explore a career at GDIT and you’ll find endless opportunities to grow alongside colleagues who share your ambition to deliver your best work.