Position Summary The Senior System Administrator will install, configure, administer, secure, sustain, and troubleshoot Windows- and Linux-based servers, virtual infrastructure, enterprise applications, and supporting services within the Hill CEDC. The position requires demonstrated experience supporting mission-critical data center operations, applying approved cybersecurity controls, managing system configurations, and coordinating maintenance activities in accordance with established change-management processes Essential Duties & Responsibilities: • Installs, configures, administers, maintains, and decommissions physical and virtual Windows and Linux servers within the Hill CEDC environment.    • Performs operating system installation, configuration, patching, hardening, upgrades, and lifecycle maintenance in accordance with approved security and change-management processes.    • Administers virtualized environments, including creating, configuring, monitoring, migrating, and retiring virtual machines and associated resources.    • Diagnoses and resolves system, operating system, application, virtualization, storage, network-connectivity, and performance issues to maximize availability and operational service levels.    • Coordinates with hardware, network, cybersecurity, database, storage, and application-support personnel to troubleshoot and resolve infrastructure incidents and service requests.    • Configures and maintains Windows- and Linux-based services, including user authentication, directory services, domain services, DNS, DHCP, file services, print services, and system logging, as applicable.    • Monitors server health, system performance, capacity, availability, event logs, and security alerts; takes corrective action or escalates issues as required.    • Implements and maintains approved operating system security configurations, vulnerability remediation actions, security patches, antivirus or endpoint-security tools, and compliance settings.    • Supports assessment and remediation of cybersecurity vulnerabilities, misconfigurations, and findings in coordination with cybersecurity personnel and system owners.    • Maintains privileged-access controls, account administration, group memberships, and role-based access in accordance with approved procedures and least-privilege principles.    • Supports installation, configuration, and sustainment of enterprise applications and supporting middleware in coordination with application owners and vendors.    • Performs software installation, licensing support, version upgrades, and configuration changes while maintaining accurate system documentation.    • Develops, maintains, and executes standard operating procedures (SOPs), system-administration guides, configuration baselines, and troubleshooting documentation.    • Documents system configurations, dependencies, maintenance actions, incidents, changes, and recovery procedures under configuration-management control.    • Supports End-of-Life/End-of-Support (EOL/EOS) planning, technology refresh efforts, migration planning, and market research for replacement software and infrastructure commodities.    • Participates in approved change-management, maintenance-window, outage-notification, and service-restoration processes.    • Supports Portable Operating Data Center (POD) systems, including installation, configuration, monitoring, maintenance, and upgrades; supports short-notice travel to remote sites as required.    • Performs other related duties as assigned.    Education, Certification & Experience Requirements • Bachelor’s degree in Information Technology, Computer Science, Cybersecurity, Business, or a related field; equivalent relevant professional experience may be considered. • 4+ years of progressively responsible system-administration experience**, including experience supporting enterprise Windows and Linux server environments. • Active Secret Clearance (or ability to obtain/maintain) • CompTIA Security+ Certification is Required • CompTIA Server+ and/or CompTIA Linux+ preferred • Microsoft Windows Server or Azure administration certification preferred • Red Hat Certified System Administrator (RHCSA) or comparable Linux certification preferred • VMware Certified Professional (VCP) or comparable virtualization certification preferred • ITIL Foundation preferred Knowledge, Skills & Abilities: • Demonstrated experience administering and troubleshooting Windows Server and Linux operating systems in an enterprise or data-center environment.    • Experience supporting physical servers, virtual machines, hypervisors, and enterprise virtualization platforms.    • Knowledge of Active Directory, Group Policy, DNS, DHCP, authentication services, file services, and access-control administration.    • Knowledge of system patching, vulnerability remediation, endpoint security, operating-system hardening, and security compliance requirements.    • Experience with system monitoring, log analysis, performance tuning, capacity management, and incident response.    • Knowledge of backup, restore, replication, and disaster-recovery concepts and procedures.    • Experience using configuration-management, ticketing, asset-management, and change-management processes.    • Ability to develop and maintain technical documentation, SOPs, diagrams, configuration baselines, and system-administration records.    • Ability to work independently, prioritize multiple tasks, communicate technical issues clearly, and coordinate effectively with government personnel, vendors, and contractor teams.    • Ability to support occasional temporary changes to work schedules and short-notice travel requirements.    Working Conditions/Working Environment/Physical Demands • Basic office work environment at government facility location. • Hours of operation are M-F between 0600-1800. • Project requirements (including patching) may require temporary adjustment of work hours/days. • This position requires onsite work at Hill Air Force Base; telework is not approved • Position may require work in a data-center environment, including standing, walking, lifting or moving IT equipment, and working around server racks, cabling, and cooling systems. • Duties are subject to change based on customer requirements.