Senior Systems Administrator

Remote from: USA
Salary, yearly, USD: 137,100 - 244,100
Department: DevOps & Infrastructure
Employment type: Full Time,
Job posted: 14 May 2026
Apply before: 14 Jun 2026
Experience level: Senior
Views / Applies: 31 / 6

ManTech delivers technology-driven innovation, develops game-changing solutions, and delivers mission-focused technologies for defense and federal civilian agencies.

Defense & Space
1968

Actively Hiring

AI Summary

MANTECH is seeking a Senior Systems Administrator to join their CASTLE-NET Program team in a fully remote role supporting the Department of Defense. The position involves managing Windows, Linux, and VMware environments, leading technology assignments, and ensuring IT infrastructure reliability and security. Candidates need 8+ years of experience, a Secret clearance, and relevant certifications like Microsoft Windows Server or RHCSA. The role offers a competitive salary range and the opportunity to work on impactful defense projects.

Job Complexity

Easy Hard

AI Insight The role requires a high level of expertise in multiple operating systems, virtualization, and scripting, along with leadership experience and a security clearance, making it challenging but not the hardest.

Salary Analysis

AI Insight The offered salary range of $137,100-$244,100 is significantly above the US market average for Senior Systems Administrators (typically $90k-$160k), reflecting the specialized nature of the role, security clearance requirement, and federal contracting.

Key Skills

Systems Administration Windows Server Linux VMware vSphere PowerShell Bash Security Clearance DoD 8140 Scripting IT Infrastructure

Cover Letter Sample

Dear Hiring Manager,

I am writing to express my strong interest in the Senior Systems Administrator position at MANTECH. With over 10 years of experience managing complex Windows, Linux, and VMware environments, I am confident in my ability to contribute to the CASTLE-NET Program. My background includes leading major technology upgrades, optimizing system performance, and ensuring security compliance in DoD settings.

I hold a Secret clearance and possess key certifications such as Microsoft Certified: Windows Server and RHCSA. I am proficient in scripting with PowerShell and Bash, and I have a proven track record of delivering reliable IT services to government clients. I am eager to bring my technical expertise and leadership skills to MANTECH's mission of supporting the nation's defense.

Thank you for considering my application. I look forward to the opportunity to discuss how my experience aligns with your needs.

Sincerely, [Your Name]

Possible Interview Questions

Describe your experience managing a mixed Windows and Linux environment. How do you ensure consistency and security across both?

I have managed environments with both Windows Server and Red Hat/CentOS. I ensure consistency by using centralized management tools like Active Directory for Windows and LDAP for Linux, and by enforcing group policies and configuration management tools like Ansible. Security is maintained through regular patching, vulnerability scanning, and adherence to STIGs.

Can you walk me through a complex project you led involving virtualization? What challenges did you face and how did you overcome them?

I led a project to migrate on-premises VMs to a new VMware vSphere cluster. Key challenges included minimizing downtime and ensuring data integrity. I planned the migration in phases, used VMware vMotion for live migrations, and tested rollback procedures. The project was completed ahead of schedule with zero data loss.

How do you stay current with evolving technologies and maintain certifications?

I regularly attend webinars, take online courses, and participate in professional communities. I set aside time each week for self-study and pursue certifications like RHCE and VCP to validate my skills. For DoD 8140 compliance, I ensure I maintain IAT Level II certification through continuous education.

Describe a time you had to troubleshoot a critical system failure. What was your approach?

Once, a critical database server experienced a kernel panic. I quickly isolated the server, restored from backup to a standby system, and analyzed logs to identify a memory module issue. I coordinated with hardware support to replace the faulty component and implemented monitoring to prevent recurrence.

How do you approach documenting system configurations and changes?

I use a combination of version-controlled documentation (e.g., Confluence) and automated tools like Ansible for configuration management. I document all changes with clear descriptions, impact assessments, and rollback plans. Regular reviews ensure documentation stays up-to-date and accessible to the team.

General information

Requisition # R67726 Locations USA-Remote Work Posting Date 05/13/2026 Security Clearance Required Secret Remote Type Fully Remote Time Type Full time

Description & Requirements

Shape the future of defense with MANTECH! Join a team dedicated to safeguarding our nation through advanced tech and innovative solutions. Since 1968, we’ve been a trusted partner to the Department of Defense, delivering cutting-edge projects that make a real impact. Dive into exciting opportunities in Cybersecurity, IT, Data Analytics and more. Propel your career forward and be part of something extraordinary. Your journey starts now—protect and innovate with MANTECH!

MANTECH seeks a motivated, career and customer-oriented Senior Systems Administrator to join our CASTLE-NET Program team. This is a remote position.

Be a part of an agile team to provide innovative, customer focused, and cost-effective integrated enterprise IT support services in support of the client’s vision of engineering solutions for the Nation’s toughest challenges.

Responsibilities include but are not limited to:

Managing and maintaining the IT infrastructure to ensure reliability, performance, and security across Windows, Linux, and VMware environments.
Planning and leading major technology assignments while providing leadership to ensure technical requirements and project objectives are met.
Installing, configuring, and supporting servers and virtualized environments in close coordination with IT teams, application developers, and stakeholders.
Evaluating performance results and recommending major changes that affect short-term project growth and overall success.
Interfacing with senior management regarding decision-making and domain knowledge that may have a critical impact on project implementation.
Delivering world-class IT services and responsive customer support to exceed the expectations of USACE OCIO/G-6 IT end-users.
Functioning as a technical expert across multiple project assignments to deliver secure, innovative, and modernized technological solutions.

Minimum Qualifications:

Bachelor’s degree in Information Technology or related field; or an Associate degree with 10+ years of experience; or 12+ years of relevant experience.
Requires 8+ years of progressively responsible experience in systems administration for Windows, Linux, or VMware environments.
Comprehensive knowledge of operating systems such as Windows Server, Red Hat, and CentOS, as well as virtualization technologies like VMware vSphere.
Proficiency in scripting languages including PowerShell, Bash, or Python, and experience with system monitoring and performance tuning.
Experience creating, maintaining, and communicating complex information technology documentation and system configurations.
Possession and maintenance of relevant certifications such as Microsoft Certified: Windows Server, RHCSA, RHCE, or VCP.
Must maintain a DoD 8140 IAT Level II certification to comply with mission security and baseline requirements.

Preferred Qualifications:

Familiarity with the USACE IT environment, regulatory requirements, and data security best practices.

Clearance Requirements:

Must possess a Secret security clearance prior to starting this position.

Physical Requirements:

The person in this position must be able to remain in a stationary position 50% of the time. Occasionally move about inside the office to access file cabinets, office machinery, or to communicate

The projected compensation range for this position is $137,100.00-$244,100.00. There are differentiating factors that can impact a final salary/hourly rate, including, but not limited to, Contract Wage Determination, relevant work experience, skills and competencies that align to the specified role, geographic location (For Remote Opportunities), education and certifications as well as Federal Government Contract Labor categories. In addition, MANTECH invests in its employees beyond just compensation. MANTECH’s benefits offerings include, dependent upon position, Health Insurance, Life Insurance, Paid Time Off, Holiday Pay, short-term and long-term Disability, Retirement and Savings, Learning and Development opportunities, wellness programs as well as other optional benefit elections.
MANTECH considers all qualified applicants for employment without regard to disability or veteran status or any other status protected under any federal, state, or local law or regulation.
If you need a reasonable accommodation to apply for a position with MANTECH, please email us at [email protected] and provide your name and contact information.

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