Linux System Administrator - Secret Clearance

Marathon TS is seeking an experienced Systems Administrator to join a dynamic team.

Description:

We are seeking a highly experienced and hands-on candidate to support research, development, and defense systems software, hardware, and network integration laboratory. This role is critical to enabling engineers and developers to design, build, integrate, and research complex mission systems in both standalone, on-premises, and cloud-based environments. The ideal candidate brings deep technical expertise across Linux-based systems administration and infrastructure, combined with strong organizational and operational discipline required for classified environments. This position requires a proactive problem solver who thrives in dynamic lab settings and can manage multiple systems, configurations, and priorities simultaneously. Additional responsibilities include: (1) Plan, design, deploy, configure, and maintain secure lab environments supporting software, hardware, and network integration efforts; (2) Install, configure, and troubleshoot servers, workstations, and, storage systems; (3) Support integration of complex systems including embedded hardware, simulation environments, and, test

platforms; (4) Create and manage system baselines, containers, virtualized environments, directory objects, configurations, and documentation in accordance with DoD RMF, ATO, and CMMC security and compliance requirements; (5) Provide hands-on support for system builds, upgrades, patching, and troubleshooting in lab and test environments; (6) Develop and maintain automation scripts and tools to streamline system provisioning and maintenance; (7) Monitor system performance, reliability, and security posture; proactively resolve issues; (8) Maintain

inventory and lifecycle management of lab assets and infrastructure; and (9) Support incident response, audit readiness, and compliance

inspections.

Requirements:

Required Clearance: Ability to obtain a Secret DoD Security Clearance.

Preferred Clearance: Active DoD Security Clearance (Secret/Top Secret, with eligibility for SCI as required).

Citizenship: Candidate must be a United States citizen.

Education:

BS in Information Technology, Computer Science, Engineering or related technical field.

Experience:

3-5 years of experience in systems administration in complex, mission-critical environments.

3+ years of DoD/Federal work experience.

Required Skills:

Demonstrated experience working in CUI, and classified environments with strong understanding of security protocols and operational

constraints.

Strong hands-on experience with: Linux-based system administration in a virtualized environment (e.g., VMware, ProxMox).

Software maintenance using package management software and compilation from source when required.

Storage systems and backup solutions.

Excellent troubleshooting and problem-solving abilities.

Hunger to learn and develop cross-functional skills.

Linux certifications (e.g., LFCS, or Linux +).

DCWF Work Role 451 compliant.

Desired Skills:

Strong organizational skills with the ability to manage multiple systems, configurations, and priorities.

Integration with hardware and software systems covering various operating systems and interfaces.

Networking fundamentals (routing, switching, firewalls, VLANs).

Proficiency with scripting and automation (e.g., PowerShell, Bash, Python).

Experience implementing and maintaining security controls (STIGs, SCAP, patching, hardening, CMMC requirements).

Experience with FPGA-based or embedded systems integration in lab environments.

Experience supporting defense or aerospace integration labs or test environments.

Familiarity with DevSecOps practices and CI/CD pipeline infrastructure.

Experience with containerization technologies (e.g., Docker, Kubernetes).

Knowledge of configuration management tools (e.g., Ansible, Puppet, Chef).

Experience with cross-domain solutions and multi-level security (MLS) environments.

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Marathon TS is committed to the development of a creative, diverse and inclusive work environment. In order to provide equal employment and advancement opportunities to all individuals, employment decisions at Marathon TS will be based on merit, qualifications, and abilities. Marathon TS does not discriminate against any person because of race, color, creed, religion, sex, national origin, disability, age or any other characteristic protected by law (referred to as "protected status ").