Linux System Administrator

About the role

G6 Cyber Solutions (G6CS) delivers innovative technology solutions that enhance national security and support critical military operations. We are seeking a motivated and mission-oriented Linux System Administrator to join our team in support of Air Force operations at Lackland AFB. In this role, you will manage and secure internal systems, ensure compliance with Department of War (DoW) standards, and optimize network infrastructure in a classified environment.

Responsibilities

• Security & Compliance:
  • Conduct regular security assessments using ACAS scans to identify, review, and remediate vulnerabilities
  • Enforce security postures and apply STIGs across networks using GPOs
  • Maintain automated security compliance scanning (e.g., SCAP cron jobs) to ensure adherence to security baselines
  • Track and monitor patching and STIG applications to maintain network health and compliance
• System Administration & Automation:
  • Manage system infrastructure including configuration, installation, administration, and optimization
  • Develop, deploy, and maintain Ansible roles and playbooks to automate backups, patching, repository configurations, and recurring tasks
  • Execute scheduled patches, monthly updates, and routine maintenance across RHEL and Windows server environments
  • Configure, execute, and verify full system backups and disaster recovery solutions (e.g., ReaR)
• User & Access Management:
  • Administer user lifecycle management, including auditing for stale accounts and automating user deactivation via PowerShell
  • Manage service account authentications and privilege escalation rules
  • Administer centralized authentication and authorization using Red Hat Identity Management (IdM)
• Infrastructure Management:
  • Manage virtualization infrastructure using Red Hat Virtualization (RHV) or Red Hat OpenShift Virtualization
  • Manage networking switches, routers, and firewalls in DoD-compliant environments
  • Manage HPC and AI clusters using NVIDIA Base Command Manager (BCM)
  • Provision and manage software installations across network endpoints
• Documentation & Support:
  • Author and maintain SOPs for administrative processes, vault management, certificate updates, and disaster recovery
  • Document system infrastructure for users, support personnel, developers, IA personnel, and accreditors
  • Provide Tier II/III technical support for user issues and system troubleshooting

Requirements

• Must be a U.S. Citizen
• Active TS/SCI clearance eligibility required
• Experience in system administration across Windows and Linux/RHEL environments, including configuration, installation, and optimization
• Proven ability to manage hardware, software, and utilities for installation, modification, troubleshooting, maintenance, and upgrades
• Experience with security assessments, vulnerability remediation, and applying STIGs using automated compliance tools
• Experience with user lifecycle management and account administration
• Experience executing system patches within DoW timelines (3 business days for critical, 10 business days for routine)
• Experience with system backups, disaster recovery solutions, and restoring critical services within SLA timelines
• Understanding of both Linux and Windows command-line interfaces (CLI)
• Experience developing and maintaining Standard Operating Procedures (SOPs)
• CompTIA Security+ certification (minimum)

Nice-to-Have Qualifications

• Experience in Department of War intelligence communities
• Experience with security standards as defined by NSA, NIST, and/or USCYBERCOM
• Experience developing automated scripts (PowerShell, Bash) and using automation platforms such as Ansible
• Experience with SCAP, ACAS, SIEM, and HIDS/NIDS toolsets
• Experience with virtualization platforms (Red Hat Virtualization/OpenShift Virtualization)
• Experience with Red Hat Identity Management (IdM) or similar centralized authentication systems
• Experience with disaster recovery solutions such as ReaR (Relax-and-Recover)
• Experience with High-Performance Computing (HPC) cluster management tools
• Red Hat Certified System Administrator (RHCSA) or additional certifications in system administration or cybersecurity

Location: On-Site, San Antonio, TX