Linux Systems Administrator, Sr. with Security Clearance

Caelum Research Corporation; Aberdeen (MD); On-site; USD 100,000 - 150,000; Full time

Job summary

Caelum Research Corporation seeks a Senior Linux Systems Administrator to support a DoD IT services contract at Aberdeen Proving Ground, MD. This on-site role requires expertise across RHEL, automation, and high-availability systems to deliver mission-critical government IT services.

The ideal candidate will mentor junior staff, implement automated deployment, and ensure security compliance using STIGs and ACAS. DoD Secret clearance and strong communications are expected.

Qualifications

• Expertise in Red Hat Enterprise Linux and middleware.
• Mentorship and senior technical guidance to junior staff.
• Automation, deployment, and configuration management experience.
• Scripting in Bash, Python, PowerShell, Ruby, or Perl.
• High-availability, clustering, load balancing, and virtualization.
• Foundational networking concepts and troubleshooting (TCP/IP, firewalls, routing).
• DISA STIGs security hardening and compliance.
• ACAS vulnerability scanning experience.
• Windows server administration familiarity.
• Database installation and migration knowledge.

Responsibilities

• Install, configure, and manage Red Hat Linux and middleware.
• Provide senior technical guidance and mentorship to team members.
• Manage automated install, build and deployment workflows.
• Create and maintain scripts to automate tasks.
• Build and sustain HA infrastructure including clustering and virtualization.
• Troubleshoot network, performance, and system issues.
• Monitor systems and perform capacity planning and tuning.
• Apply STIGs and manage IAM configurations to ensure security.
• Plan OS upgrades and environment migrations with minimal downtime.

Skills

RHEL Linux

Automation

Scripting (Bash/Python/PowerShell/Ruby

High-Availability

Networking

Security STIGs

System monitoring

Virtualization

Windows Admin

ACAS vulnerability scanning

Database basics

Education

Bachelor's degree in IT related field

Associate’s degree

Master’s degree

DoD 8570.01 Compliance (Security+ or equivalent IAT Level II)

CE certification (Computing Environment)

RHCSA / RHCE preferred

Tools

RHCSA/RHCE

ACAS

Job description

• Clearance Requirement: DoD Secret
• Location: On-site at Aberdeen Proving Ground, MD Role Overview

Senior Linux Systems Administrator

• Position: Systems Administrator IV
• Supported Program: U.S. Army Test & Evaluation Command
• Clearance Requirement: DoD Secret
• Location: On-site at Aberdeen Proving Ground, MD Role Overview

We are seeking a highly skilled Senior Linux Systems Administrator to support a critical government IT services contract. The successful candidate will act as a primary subject matter expert for Linux infrastructure, automation, and high-availability systems. This role requires deep technical expertise in Red Hat Enterprise Linux (RHEL), enterprise production environments, and network storage. As a senior member of the team, the candidate will also provide technical guidance and mentorship to other IT professionals.

Core Responsibilities & Technical Qualifications

• Linux Systems Administration: Install, configure, and manage UNIX variants, with a heavy emphasis on Red Hat Linux server operating systems and associated middleware.
• Technical Mentorship: Act as a senior technical resource, providing mentorship, guidance, or team lead support to junior administrators and technical staff.
• Automation & Deployment: Manage complex production environments using automated installation, automated build and deployment, and automated configuration management frameworks.
• Scripting Proficiency: Write and utilize operating system commands and scripts to automate routine tasks, utilizing one or more of the following: Bash, Python, PowerShell, Ruby, or Perl.
• High-Availability Infrastructure: Build, maintain, and support clustered, scalable, and high-availability systems, including load balancing, web servers, application servers, and server virtualization.
• Networking & Troubleshooting: Apply foundational networking principles (TCP/IP, firewalls, routing, VLANs) to perform general network troubleshooting and resolve complex system issues.
• Performance Monitoring & Optimization: Utilize enterprise monitoring tools for event and performance monitoring. Conduct performance tuning, capacity planning, and bottleneck resolution.
• Security & Compliance: Apply Defense Information Systems Agency (DISA) Security Technical Implementation Guides (STIGs) to harden systems, remediate advanced security vulnerabilities, manage identity and access configurations, and ensure overall system security compliance.
• System Lifecycle Management: Plan and execute seamless operating system upgrades and environment migrations with minimal mission impact. Preferred Qualifications
• Vulnerability Scanning (ACAS): Experience utilizing the Assured Compliance Assessment Solution (ACAS) for vulnerability scanning, analysis, and compliance reporting.
• Windows Administration: Familiarity or experience with Microsoft server operating systems, Windows event and performance monitoring, and Microsoft middleware.
• Database Technologies: Knowledge of database technologies, including installation and configuration of database management systems and migration of databases.

Education and Experience Requirements

Candidates must meet one of the following education and experience combinations. Education must be in a directly related IT discipline (e.g., Computer Science, Information Systems, Computer/Software Engineering, Management Information Systems, or Computer Forensics/Security).

• High School Diploma / GED: Minimum of 11 years of directly related IT experience.
• Associate’s degree: Minimum of 9 years of directly related IT experience.
• Bachelor's Degree: Minimum of 7 years of directly related IT experience.
• Master's Degree: Minimum of 5 years of directly related IT experience. Certifications
• DoD Directive 8570.01 Compliance: Must possess a current Security+ certification (or equivalent IAT Level II baseline certification).
• Computing Environment (CE): Must hold at least one current Computing Environment certification, or be able to obtain one within 6 months of start. Given the technical requirements of this role, a Linux-based certification (e.g., Red Hat Certified System Administrator [RHCSA] or Red Hat Certified Engineer [RHCE]) is strongly preferred.