Principal System Administrator – Windows & Linux

About the role

RTX is seeking a Principal System Administrator to manage a mixed Windows and RedHat Enterprise Linux environment supporting critical aerospace and defense systems. The role requires deep technical expertise, a Top‑Secret clearance, and the ability to work onsite in El Segundo, CA.

Key responsibilities

• Administer Windows Server and RedHat Enterprise Linux platforms, including DNS, DHCP, AD, and server replication.
• Troubleshoot moderate to high‑complexity technical issues across hardware and operating systems.
• Design, develop, and deploy container solutions.
• Manage VMware ESXi, vCenter, and Microsoft Windows domains.
• Perform hardware RAID configuration, encryption, backup, and restore operations.
• Install and configure end‑user software applications.
• Collaborate with cybersecurity teams to enforce security requirements.
• Obtain DoD 8140/8570 certification (CompTIA Security+ CE or equivalent) within six months of start.
• Provide 24×7 system support and occasional overtime; travel up to 10% domestically.

Required profile

• U.S. citizenship with an active Top‑Secret security clearance.
• University degree or equivalent experience.
• Minimum 5 years of relevant systems administration experience.
• Ability to work full‑time onsite.

Required skills

• Windows Server internals
• RedHat Enterprise Linux fundamentals
• VMware ESXi and vCenter
• Active Directory, DNS, DHCP
• Hardware RAID and encryption technologies
• Backup and restore best practices
• Containerization (Docker/Kubernetes concepts)
• CompTIA Security+ CE or equivalent certification